US 8273735

US Patent 8,273,735: Process for Preparing Benzazepine Compounds

Title: Process for preparing benzazepine compounds or salts thereof

Current Assignee: Otsuka Pharmaceutical Co Ltd

Inventors: Yasuhiro Torisawa, Kaoru Abe, Yasuaki Muguruma, Shigekazu Fujita, Hidenori Ogawa, Naoto Utsumi, Masahiro Miyake

Filing Date: September 1, 2006

Issue Date: September 25, 2012

Abstract:
The patent describes a process for preparing benzazepine compounds or their salts, particularly 2,3,4,5-tetrahydro-1H-1-benzazepine compounds or their salts. The invention also covers intermediate compounds. The primary goal is to provide an improved industrial process for producing these compounds in high yield and purity, which are useful as intermediates for pharmaceutically active benzazepine compounds with vasopressin antagonistic activity, such as tolvaptan.

Plain-Language Overview of Independent Claims:

Independent Claim 1:
This claim describes a process for creating a benzazepine compound of a specific Formula (1) or a salt of that compound. The process involves reacting a compound of Formula (2) (a specific benzazepine compound) or its salt, with an amide compound of Formula (3) or its salt. This reaction must occur in the presence of a carbonylating agent. In Formula (1), (2), and (3), R1 and R2 are independently a "lower alkyl group" (a straight or branched chain alkyl with 1 to 6 carbon atoms, such as methyl, ethyl, propyl), and X1 and X2 are halogen atoms (fluorine, chlorine, bromine, or iodine).

Independent Claim 7:
This claim details a process for making a benzoic acid compound of Formula (4) or its salt. R1 and R2 are defined as in Claim 1 (lower alkyl groups). The process involves reacting an amide compound of Formula (11) or its salt with an oxalyl halide compound of Formula (19), where X6 and X7 are independently halogen atoms. This is one of four disclosed methods for preparing benzoic acid compounds (4), which are useful intermediates for the pharmaceutically active benzazepine compound.

Independent Claim 8:
This claim outlines a process for producing a benzoic acid compound of Formula (4) or its salt, where R1 and R2 are defined as lower alkyl groups. This process specifically involves oxidizing an amide compound of Formula (12) or its salt, where X3 is a halogen atom.

Independent Claim 9:
This claim describes a process for preparing a benzoic acid compound of Formula (4) or its salt, with R1 and R2 being lower alkyl groups. This method involves hydrolyzing an amide compound of Formula (13) or its salt, where X3 is a halogen atom.

Independent Claim 10:
This claim focuses on a process for synthesizing a benzoic acid compound of Formula (4) or its salt, where R1 and R2 represent lower alkyl groups. The process requires oxidizing an amide compound of Formula (14) or its salt.

Independent Claim 11:
This claim sets forth a process for preparing a 2,3,4,5-tetrahydro-1H-1-benzazepine compound of Formula (10) or a salt thereof. R1, R2, and X1 are defined as in Claim 1. The process involves reducing a benzazepine compound of Formula (1) or its salt in the presence of a hydrogenating agent. Crucially, the hydrogenating agent is used in an amount of 0.1 to 1 mole per 1 mole of the compound (1). The patent highlights that this specific molar ratio helps in achieving high yield and purity by minimizing undesirable dehalogenating reactions. The hydrogenating agent can be lithium aluminum hydride, sodium borohydride, zinc borohydride, or diborane.

Litigation:
US Patent 8,273,735 is currently active and is involved in multiple litigations. Several cases have been filed in the Delaware District Court, including Otsuka Pharm. Co., Ltd. v. Zenara Pharma Private Ltd., 26-0181 (D. Del.), filed February 19, 2026, concerning Jynarque® (tolvaptan tablets). Additionally, there is a US case filed in the Court of Appeals for the Federal Circuit (CAFC), No. 24-2297. In Otsuka Pharmaceutical Co. v. Lupin Ltd., No. 24-2297 (Fed. Cir. May 21, 2026), a Federal Circuit panel affirmed a judgment that Lupin's tolvaptan ANDA process does not infringe Otsuka's U.S. Patent Nos. 8,273,735 and 8,501,730. The court also found the asserted method claims invalid as obvious over Kondo's 1999 paper. The patent claims teach reducing the amount of sodium borohydride hydrogenating agent to 0.25–1 molar equivalents per mole of benzazepine precursor to reduce impurities. Lupin's process was found not to infringe as it uses at least 1.2 molar equivalents. The patent is set to expire on August 14, 2028.

US Patent 8,273,735 is currently involved in multiple litigations.

Here's a summary of known cases:

• Otsuka Pharmaceutical Co., Ltd. v. Lupin Ltd.

  • Plaintiff(s): Otsuka Pharmaceutical Co., Ltd.
  • Defendant(s): Lupin Limited and Lupin Pharmaceuticals, Inc.
  • Jurisdiction: U.S. Court of Appeals for the Federal Circuit (on appeal from the District of Delaware)
  • Case Number: 24-2297
  • Filing Date: September 10, 2024 (Federal Circuit appeal filing date)
  • Outcome/Status: On May 21, 2026, a Federal Circuit panel affirmed a district court's judgment that Lupin's tolvaptan ANDA process does not infringe Otsuka's U.S. Patent Nos. 8,273,735 and 8,501,730. The court also found the asserted method claims invalid as obvious over Kondo's 1999 paper. The district court trial opinion, issued July 31, 2024, found that Lupin did not infringe the patents-in-suit and that the asserted claims of the '735 patent were obvious.

• Otsuka Pharmaceutical Co., Ltd. v. Zenara Pharma Private Limited

  • Plaintiff(s): Otsuka Pharmaceutical Co., Ltd.
  • Defendant(s): Zenara Pharma Private Limited, and a multitude of other defendants including Accord Healthcare Inc., Ajanta Pharma Ltd., Alembic Pharmaceuticals Inc., Alkem Laboratories Ltd., Amneal Pharmaceuticals LLC, Apotex Corp., Aurobindo Pharma Ltd., Cadila Healthcare Ltd., Hetero Drugs Ltd., Lupin Limited, Macleods Pharma USA, Inc., MSN Laboratories Pvt. Ltd., Optimus Pharma Pvt. Ltd., Prinston Pharmaceutical Inc., Raks Pharma Pvt. Ltd., Sandoz Inc., Teva Pharmaceuticals USA Inc., Unichem Laboratories Ltd., and Zydus Lifesciences Limited.
  • Jurisdiction: Delaware District Court.
  • Case Number: 1:26-cv-00181. (Note: An earlier case with similar parties has case number 19-1938 and 19-cv-01938-LPS, filed in 2019, last retrieved July 27, 2021 and September 21, 2022. It is possible this is related or a continuation.)
  • Filing Date: February 19, 2026.
  • Outcome/Status: This is a Patent - Abbreviated New Drug Application (ANDA) case. The case is active.

• Additional cases filed in Delaware District Court (details pending further search)

  • Multiple cases are listed as filed in the Delaware District Court for US8273735B2 on Google Patents and Unified Patents, but specific details (plaintiff, defendant, case number, filing date, status) beyond the jurisdiction are not immediately available without deeper search into each specific case entry. These include cases with identifiers: 1:24-cv-00740, 1:26-cv-00232, 1:25-cv-00318, 1:21-cv-00900, 1:23-cv-00710, and 1:22-cv-00513. The case 1:21-cv-00900-RGA is Otsuka Pharmaceutical Co., Ltd. v. Lupin Limited, which was appealed as 24-2297 to the Federal Circuit.

Proceedings overview

The USPTO Open Data Portal API currently reports no AIA trial proceedings (Inter Partes Review, Post-Grant Review, or Covered Business Method) on file for US Patent 8,273,735. Despite active litigation, including a Federal Circuit decision affirming a district court's finding of obviousness for asserted claims, there is no public record of a corresponding AIA trial at the PTAB.

Strategic summary

Based on the available information, there are no PTAB proceedings (IPR, PGR, or CBM) on record for US Patent 8,273,735. This means that, unlike cases where claims might be canceled or sustained by the PTAB, the claims of US8273735 have not been directly challenged or affirmed through these specific administrative trial processes.

The litigation summary indicates that the asserted method claims of US8273735 were found invalid as obvious over Kondo's 1999 paper by a district court, and this judgment was affirmed by the Federal Circuit in Otsuka Pharmaceutical Co. v. Lupin Ltd. (Case No. 24-2297). This invalidation, however, stems from district court proceedings rather than a PTAB Final Written Decision. As such, the specific claims invalidated by the district court are effectively canceled for the parties involved in that litigation, but the PTAB itself has not rendered a decision on the patentability of any claims.

The absence of PTAB activity means there is no estoppel under 35 U.S.C. § 315(e)(2) for potential petitioners, as no IPR has gone to a final written decision. Therefore, a defendant facing assertion of this patent could still pursue an IPR on any grounds of patentability (e.g., §§ 102, 103) based on prior art, including Kondo's 1999 paper if applicable, without being barred by prior PTAB decisions.

The lack of PTAB challenges for a patent involved in significant ANDA litigation could indicate several factors:

• The prior art landscape might have been complex, leading litigants to prioritize district court defenses.
• Strategic decisions by potential petitioners to avoid PTAB.
• The claims of US8273735 might have been structured in a way that made them less amenable to a straightforward IPR challenge, or the best prior art was already being leveraged in district court.

Recommended next steps

Given the absence of PTAB activity for US Patent 8,273,735:

• For a defendant currently being asserted against: The district court's finding that asserted method claims of US8273735 are invalid as obvious (affirmed by the Federal Circuit) provides a strong defense against those specific claims, particularly for processes that fall outside the claimed molar equivalent range. It is crucial to obtain and review the full district court opinion from Otsuka Pharmaceutical Co., Ltd. v. Lupin Limited (Delaware District Court, Case No. 1:21-cv-00900-RGA) and the Federal Circuit affirmance (Case No. 24-2297). This provides a direct legal precedent for invalidity on specific claims.
• Consideration for new PTAB petitions: The absence of prior IPRs means there's no PTAB-imposed estoppel. If a defendant has new prior art or new arguments based on existing art not fully litigated in the district court context, filing a new IPR petition remains an option. However, careful consideration should be given to the prior district court's obviousness findings and whether a PTAB petition would offer a distinct advantage or risk inconsistent rulings.
• Monitoring: Continue to monitor the USPTO PTAB E2E system and public dockets for any future filings against US8273735, especially given its active litigation status and impending expiration in 2028.

It is important to reiterate that while the district court found claims invalid, this judgment pertains to the parties and scope of that particular litigation. The patent itself has not been subjected to a PTAB trial.

External Resources Cited:

• US8273735B2 - Process for preparing benzazepine compounds or salts thereof - Google Patents. https://patents.google.com/patent/US8273735B2/en (Accessed 2026-05-22).
• Case 1:21-cv-00900-RGA - Document 357 - D.Del. - CourtListener.com. https://www.courtlistener.com/docket/60072046/357/otsuka-pharmaceutical-co-ltd-v-lupin-limited/ (Accessed 2026-05-22).
• Case 1:21-cv-00900-RGA - Document 358 - D.Del. - CourtListener.com. https://www.courtlistener.com/docket/60072046/358/otsuka-pharmaceutical-co-ltd-v-lupin-limited/ (Accessed 2026-05-22).
• Case 1:21-cv-00900-RGA - Document 359 - D.Del. - CourtListener.com. https://www.courtlistener.com/docket/60072046/359/otsuka-pharmaceutical-co-ltd-v-lupin-limited/ (Accessed 2026-05-22).
• Case 1:21-cv-00900-RGA - Document 360 - D.Del. - CourtListener.com. https://www.courtlistener.com/docket/60072046/360/otsuka-pharmaceutical-co-ltd-v-lupin-limited/ (Accessed 2026-05-22).
• Case 1:21-cv-00900-RGA - Document 361 - D.Del. - CourtListener.com. https://www.courtlistener.com/docket/60072046/361/otsuka-pharmaceutical-co-ltd-v-lupin-limited/ (Accessed 2026-05-22).
• US8273735 - Process for preparing benzazepine compounds or salts thereof - Litigation. https://portal.unifiedpatents.com/patents/US8273735/litigation (Accessed 2026-05-22).
• Case 24-2297 - Otsuka Pharmaceutical Co. v. Lupin Ltd. - CourtListener.com. https://www.courtlistener.com/docket/69089947/otsuka-pharmaceutical-co-ltd-v-lupin-limited/ (Accessed 2026-05-22).## Proceedings overview

The USPTO Open Data Portal API currently reports no AIA trial proceedings (Inter Partes Review, Post-Grant Review, or Covered Business Method) on file for US Patent 8,273,735. Despite active litigation that led to a Federal Circuit decision affirming a district court's finding of obviousness for asserted claims, there is no public record of a corresponding AIA trial at the PTAB.

Strategic summary

Based on the available information, there are no PTAB proceedings (IPR, PGR, or CBM) on record for US Patent 8,273,735. This means that, unlike cases where claims might be canceled or sustained by the PTAB, the claims of US8273735 have not been directly challenged or affirmed through these specific administrative trial processes.

The litigation summary indicates that the asserted method claims of US8273735 were found invalid as obvious over Kondo's 1999 paper by a district court, and this judgment was affirmed by the Federal Circuit in Otsuka Pharmaceutical Co. v. Lupin Ltd. (Case No. 24-2297). This invalidation, however, stems from district court proceedings rather than a PTAB Final Written Decision. As such, the specific claims invalidated by the district court are effectively canceled for the parties involved in that litigation, but the PTAB itself has not rendered a decision on the patentability of any claims.

The absence of PTAB activity means there is no estoppel under 35 U.S.C. § 315(e)(2) for potential petitioners, as no IPR has gone to a final written decision. Therefore, a defendant facing assertion of this patent could still pursue an IPR on any grounds of patentability (e.g., §§ 102, 103) based on prior art, including Kondo's 1999 paper if applicable, without being barred by prior PTAB decisions.

The lack of PTAB challenges for a patent involved in significant ANDA litigation could indicate several factors:

• The prior art landscape might have been complex, leading litigants to prioritize district court defenses.
• Strategic decisions by potential petitioners to avoid PTAB.
• The claims of US8273735 might have been structured in a way that made them less amenable to a straightforward IPR challenge, or the best prior art was already being leveraged in district court.

Recommended next steps

Given the absence of PTAB activity for US Patent 8,273,735:

• For a defendant currently being asserted against: The district court's finding that asserted method claims of US8273735 are invalid as obvious (affirmed by the Federal Circuit) provides a strong defense against those specific claims, particularly for processes that fall outside the claimed molar equivalent range. It is crucial to obtain and review the full district court opinion from Otsuka Pharmaceutical Co., Ltd. v. Lupin Limited (Delaware District Court, Case No. 1:21-cv-00900-RGA) and the Federal Circuit affirmance (Case No. 24-2297). This provides a direct legal precedent for invalidity on specific claims.
• Consideration for new PTAB petitions: The absence of prior IPRs means there's no PTAB-imposed estoppel. If a defendant has new prior art or new arguments based on existing art not fully litigated in the district court context, filing a new IPR petition remains an option. However, careful consideration should be given to the prior district court's obviousness findings and whether a PTAB petition would offer a distinct advantage or risk inconsistent rulings.
• Monitoring: Continue to monitor the USPTO PTAB E2E system and public dockets for any future filings against US8273735, especially given its active litigation status and impending expiration in 2028.

It is important to reiterate that while the district court found claims invalid, this judgment pertains to the parties and scope of that particular litigation. The patent itself has not been subjected to a PTAB trial.

Inventors

• Yasuhiro Torisawa
• Kaoru Abe
• Yasuaki Muguruma
• Shigekazu Fujita
• Hidenori Ogawa
• Naoto Utsumi
• Masahiro Miyake

All inventors were employed by Otsuka Pharmaceutical Co., Ltd. at the time of filing, as evidenced by the assignment to Otsuka Pharmaceutical Co., Ltd. recorded on August 13, 2009. There are no unusual patterns indicating a mass departure of inventors preceding a portfolio transfer.

Original assignee

The entity named on the issued patent is Otsuka Pharmaceutical Co., Ltd. They produce and market pharmaceutical products, including Jynarque® (tolvaptan), which embodies the claims of this patent as an intermediate for its production. Otsuka Pharmaceutical Co., Ltd. is an active, operating company.

Assignment timeline

• 2006-08-01 (executed) / recorded 2009-08-13 — Reel 023023/0488
  • Conveyance: ASSIGNMENT
  • Assignor: OGAWA, HIDENORI; UTSUMI, NAOTO; TORISAWA, YASUHIRO; FUJITA, SHIGEKAZU; ABE, KAORU; MIYAKE, MASAHIRO; MUGURUMA, YASUAKI (all inventors)
  • Assignee: OTSUKA PHARMACEUTICAL CO., LTD.
  • Correspondent: BROWDY AND NEIMARK, PLLC, 1625 K Street N.W., Suite 1000, Washington, DC, 20006.
  • Context: Initial assignment from inventors to the corporate entity.

The USPTO Assignment Center has no other recorded post-issuance assignments for US Patent 8,273,735.

Timeline diagram

timeline
    title Ownership of US 8273735
    2006 : Inventors assigned to Otsuka
    2009 : Assignment recorded
    2012 : Patent issued to Otsuka
    2019 : First litigation filed
    2026 : Active litigation ongoing

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The patent remains with Otsuka Pharmaceutical Co., Ltd., a publicly known operating pharmaceutical company.
2. Known asserter in the chain — Not present. Otsuka Pharmaceutical Co., Ltd. is the original and current assignee and is an operating company, not identified as a known NPE. They are actively litigating the patent themselves.
3. Repeat correspondent across the chain — Not present. Only one assignment from the inventors to the original assignee is recorded (Reel 023023/0488). There is no pattern of recurrence to observe for this patent's chain.
4. Cascading transfers — Not present. Only one assignment transaction is recorded, from the inventors to Otsuka Pharmaceutical Co., Ltd. (Reel 023023/0488).
5. Pre-litigation transfer — Not present. The sole recorded assignment (Reel 023023/0488) was executed on 2006-08-01 and recorded on 2009-08-13, long before the first reported litigation concerning this patent (around 2019).
6. Bankruptcy fire-sale — Not present. Otsuka Pharmaceutical Co., Ltd. is an active, operating company and has not undergone bankruptcy proceedings that resulted in the sale of this patent.
7. Privateering — Unclear. While Otsuka Pharmaceutical Co., Ltd. is asserting the patent, there is no public information or SEC filings available to confirm or deny a privateering arrangement where an NPE asserts on their behalf. Otsuka appears to be directly asserting the patent.
8. Defensive aggregator (anti-NPE) — Not present. The patent is held and asserted by Otsuka Pharmaceutical Co., Ltd., an operating company, rather than being acquired by a defensive aggregator.

Verdict

Operating-company assertion. The patent US8273735 has been consistently owned by the original assignee, Otsuka Pharmaceutical Co., Ltd., since its inception (Reel 023023/0488). Otsuka Pharmaceutical Co., Ltd. is an operating pharmaceutical company that manufactures and sells products related to the claimed invention, specifically the vasopressin antagonist tolvaptan, and is actively asserting this patent in litigation to protect its commercial interests.

https://assignmentcenter.uspto.gov/patent/index.html

Most Relevant Prior Art for US Patent 8,273,735

The following patent documents are cited as prior art in US Patent 8,273,735. This analysis focuses on their potential anticipation under 35 U.S.C. § 102.

Cited Patent Documents:

1. JP-A-4-154765
   • Full Citation: JP 4-154765 A
   • Publication Date: June 1, 1992 (Filing date: November 27, 1990)
   • Brief Description: This Japanese patent application describes certain benzazepine compounds and their use as vasopressin antagonists. It is explicitly mentioned in US8273735 as disclosing "a pharmaceutically active benzazepine compound having vasopressin antagonistic activity, e.g. the compounds (10)" and also that "benzoic acid compounds of the above formula (4) are useful as an intermediate for preparing a pharmaceutically active benzazepine compound having vasopressin antagonistic activity".
   • Potential Anticipation (35 U.S.C. § 102): JP-A-4-154765 likely anticipates the compounds themselves (compounds of Formula (1) and (10), and intermediates of Formula (4)) rather than the processes for preparing them, which is the focus of US8273735. Specifically, the abstract and description of US8273735 state that compounds (1) and (4) are "useful as an intermediate for preparing a pharmaceutically active benzazepine compound having vasopressin antagonistic activity, e.g. the compounds (10) as mentioned hereinafter (cf. JP-A-4-154765)". Therefore, this prior art may anticipate the compounds themselves if they fall within its scope. However, since US8273735 claims are directed to processes for preparing these compounds, and specific processes for intermediates, JP-A-4-154765 would only anticipate the claims directed to the compounds themselves if they were present, or potentially serve as a basis for obviousness for the processes if the methods were similar. Given the independent claims of US8273735 are for specific processes, JP-A-4-154765 would serve more as a source for the known compounds that the claimed processes produce, rather than anticipating the novel processes themselves. The Federal Circuit found asserted method claims (process claims) invalid as obvious over Kondo's 1999 paper, which is a different reference, suggesting JP-A-4-154765 might describe the end product and its utility, but not necessarily the specific improved processes claimed in US8273735.

(Self-correction: The provided patent text snippet for US8273735 mentions the Kondo paper and Torisawa et al. as scientific publications, not patent documents. The question specifically asks for patent citations. I need to make sure I only include actual patent documents from the 'References Cited' section of the Google Patents page for US8273735.)

To accurately complete this task, I need to consult the "References Cited" section directly from the Google Patents page for US8273735. The search results above provide snippets that mention JP-A-4-154765, but I need to ensure I'm listing all patent citations. I will perform a more targeted search for the "References Cited" section of the specific patent.

Let's refine the search to directly pull the references from the Google Patents page for US8273735.### Most Relevant Prior Art for US Patent 8,273,735

Based on the provided authoritative patent text for US8273735, the primary patent prior art explicitly referenced is JP-A-4-154765. Other references mentioned in the patent text, such as Kondo et al. and Torisawa et al., are scientific publications (non-patent literature).

Here is an analysis of the cited patent document:

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1. JP-A-4-154765

• Full Citation: JP 4-154765 A
• Publication/Filing Date: Publication Date: June 1, 1992. (The priority date for US8273735 is September 2, 2005, making this a clear prior art reference).
• Brief Description: This Japanese patent application describes certain benzazepine compounds, specifically 2,3,4,5-tetrahydro-1H-1-benzazepine compounds, and their salts, and identifies their utility as vasopressin antagonists. It also covers intermediate compounds for preparing these pharmaceutically active substances. The patent US8273735 explicitly references JP-A-4-154765 as disclosing "a pharmaceutically active benzazepine compound having vasopressin antagonistic activity, e.g. the compounds (10)" and further notes that "the benzoic acid compounds of the above formula (4) are useful as an intermediate for preparing a pharmaceutically active benzazepine compound having vasopressin antagonistic activity (cf. JP-A-4-154765)".
• Which Claim(s) it Potentially Anticipates Under 35 U.S.C. § 102:
  • JP-A-4-154765 is cited in US8273735 primarily for disclosing the compounds themselves (e.g., compounds of Formula (10) as pharmaceutically active agents, and compounds of Formula (1) and (4) as intermediates) and their known vasopressin antagonistic activity, rather than the specific processes claimed in US8273735.
  • Since the independent claims of US8273735 (Claims 1, 7, 8, 9, 10, 11) are all directed to processes for preparing these benzazepine or benzoic acid compounds, JP-A-4-154765 would not directly anticipate these process claims under 35 U.S.C. § 102 if it does not describe the same processes. Instead, its primary role is likely as a reference establishing the known nature and utility of the compounds being produced by the novel processes claimed in US8273735. Therefore, while the products of the claimed processes might be known from JP-A-4-154765, the processes themselves would only be anticipated if JP-A-4-154765 explicitly detailed identical or substantially similar methods for their preparation. The US8273735 patent aims to provide an improved process for producing these known compounds, suggesting the prior art's methods might be different or less efficient.

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Obviousness Analysis of US Patent 8,273,735 Under 35 U.S.C. § 103

This analysis evaluates the obviousness of US Patent 8,273,735, which describes processes for preparing benzazepine compounds or salts thereof, under 35 U.S.C. § 103, considering the relevant prior art and the established legal precedent from the Federal Circuit.

Person Having Ordinary Skill in the Art (PHOSITA)

A person having ordinary skill in the art (PHOSITA) for US Patent 8,273,735 would likely be an organic chemist or a chemical engineer with experience in pharmaceutical synthesis, particularly in the development and optimization of synthetic routes for nitrogen-containing heterocyclic compounds, such as benzazepines. This individual would possess knowledge of common synthetic methodologies, reaction conditions, catalysts, and purification techniques, as well as an understanding of how to achieve high yields and purity in industrial-scale chemical production. They would also be familiar with literature concerning vasopressin antagonists and their synthesis.

Prior Art References

The following prior art references are considered in this obviousness analysis:

1. JP-A-4-154765 (JP '765): This Japanese patent application, published June 1, 1992, describes certain benzazepine compounds, including 2,3,4,5-tetrahydro-1H-1-benzazepine compounds and their salts, and identifies their utility as vasopressin antagonists. US8273735 explicitly references JP-A-4-154765 for disclosing the pharmaceutically active benzazepine compound (10) and the intermediate benzoic acid compounds (4), indicating that the end products and some intermediates of the claimed processes were known in the art.
2. Yasuhiro Torisawa et al., Bioorganic & Medicinal Chemistry Letters, 10 (2000), pp. 2493-2495 (Torisawa 2000): This scientific publication is explicitly cited in US8273735 as disclosing a known process (Reaction Scheme C) for preparing the benzoic acid compounds of Formula (4).
3. Kondo's 1999 paper: While the full citation is not provided in the authoritative patent text snippets, the litigation summary clearly states that "the asserted method claims [of US8273735] were found invalid as obvious over Kondo's 1999 paper" by a district court, a finding affirmed by the Federal Circuit in Otsuka Pharmaceutical Co. v. Lupin Ltd.. This paper is particularly relevant to the reduction step involving hydrogenating agents and specific molar equivalents. For the purpose of this analysis, it is assumed that Kondo's 1999 paper, as determined by the Federal Circuit, describes or suggests aspects of the reduction process for benzazepine compounds.

Analysis of Independent Claims under 35 U.S.C. § 103

Claim 1: Process for Preparing Benzazepine Compound (1)

Claim 1 describes a process for preparing a benzazepine compound of Formula (1) or its salt by reacting a compound of Formula (2) with an amide compound of Formula (3) or its salt in the presence of a carbonylating agent.

• Combination: JP-A-4-154765.
• Reasoning: JP-A-4-154765 establishes that benzazepine compounds like (1) were known and useful as intermediates for vasopressin antagonists. If JP-A-4-154765 (or other prior art) generally taught or suggested the construction of such a benzazepine core from an amino-benzazepine (2) and a substituted benzamide derivative (3) via a carbonylation reaction, a PHOSITA would have a motivation to combine these known elements. The patent itself states that compound (2) can be produced by any known process. The broad nature of "reacting... in the presence of a carbonylating agent" might be considered a conventional amidation or acylation strategy for forming the amide bond linking the benzazepine and benzoic acid moieties if similar reactions are generally known in the art for synthesizing such structures. However, without specific details from JP-A-4-154765 or other references on the exact mechanism or conditions for forming compound (1) via this specific coupling, a direct finding of obviousness purely based on JP-A-4-154765 is not fully supported by the provided patent text. The patent asserts its process provides "high yield and high purity", implying an improvement over existing methods. If prior art teaches the general structure and the desirability of creating such a bond, the motivation would be to find an efficient method to do so.

Claims 7, 8, 9, and 10: Processes for Preparing Benzoic Acid Compound (4)

These claims detail four different processes for preparing the benzoic acid compound of Formula (4) or its salt, which is an intermediate for the pharmaceutically active benzazepine compound:

• Claim 7: Reacting an amide compound (11) with an oxalyl halide (19).

• Claim 8: Oxidizing an amide compound (12).

• Claim 9: Hydrolyzing an amide compound (13).

• Claim 10: Oxidizing an amide compound (14).

• Combination: JP-A-4-154765 and Torisawa 2000.

• Reasoning: JP-A-4-154765 identifies compound (4) as a useful intermediate. Torisawa 2000 is explicitly cited in US8273735 as disclosing a known process (Reaction Scheme C) for preparing these benzoic acid compounds (4). Given that a known method for preparing compound (4) already existed (Torisawa 2000), a PHOSITA would be motivated to explore alternative or improved synthetic routes (as claimed in Claims 7-10) to achieve advantages such as higher yield, purity, cost-effectiveness, or ease of industrial scale-up.

  • Motivation for modification: If Torisawa 2000 discloses one method for preparing compound (4), and other methods (oxidation, hydrolysis, reaction with oxalyl halide) are generally known in organic synthesis for converting structurally similar precursors to carboxylic acids, a PHOSITA would have a reasonable expectation of success in applying these standard transformations. For example, oxidizing an appropriate precursor (12 or 14) to a carboxylic acid (4) is a fundamental organic reaction. Similarly, hydrolyzing an ester or nitrile (13) to a carboxylic acid (4) is a common synthetic pathway. Reacting an amide (11) with an oxalyl halide (19) to form a carboxylic acid might also be a known coupling reaction or a variation thereof. The motivation would be to overcome perceived disadvantages of the Torisawa 2000 method, such as low yield, difficult purification, or use of expensive/hazardous reagents.

Claim 11: Process for Preparing 2,3,4,5-tetrahydro-1H-1-benzazepine Compound (10)

Claim 11 describes a process for preparing compound (10) by reducing a benzazepine compound of Formula (1) or its salt in the presence of a hydrogenating agent, specifically using the hydrogenating agent in an amount of 0.1 to 1 mole per 1 mole of compound (1). The claim further specifies hydrogenating agents such as lithium aluminum hydride, sodium borohydride, zinc borohydride, or diborane.

• Combination: JP-A-4-154765 and Kondo's 1999 paper.
• Reasoning: JP-A-4-154765 established the utility and existence of compound (10) as a vasopressin antagonist. The conversion of compound (1) to compound (10) involves a reduction reaction, which is a common synthetic transformation in organic chemistry.
  • Judicial Precedent: The Federal Circuit's affirmance that the asserted method claims (including this reduction step) were invalid as obvious over Kondo's 1999 paper is highly significant. The court's finding indicates that Kondo's 1999 paper either explicitly disclosed or rendered obvious the specific limitation of using a hydrogenating agent in an amount of 0.1 to 1 mole per 1 mole of compound (1).
  • Motivation: The US8273735 patent emphasizes that this specific molar ratio (0.1 to 1 mole, preferably 0.25 to 1 mole, more preferably 0.25 to 0.5 mole for sodium borohydride) is crucial for producing compound (10) in "high yield and high purity" and "with hardly occurring undesirable dehalogenating reaction which has been occurred in the known processes". A PHOSITA, aware of the general reduction of similar compounds (e.g., from Kondo's 1999 paper or other literature on reducing benzazepines) and facing challenges with impurities or dehalogenation, would be motivated to optimize reaction conditions, including the stoichiometry of the reducing agent. Experimentation to find optimal molar ratios to achieve better purity and yield, particularly to avoid side reactions like dehalogenation, would be well within the skill of a PHOSITA. Kondo's 1999 paper, as interpreted by the court, would have provided sufficient teaching or suggestion to motivate this optimization and render the claimed range obvious.

Conclusion

Based on the analysis, particularly in light of the Federal Circuit's ruling regarding Kondo's 1999 paper:

• Claim 11 is highly likely to be obvious over a combination of JP-A-4-154765 (for the known compound and its utility) and Kondo's 1999 paper (for teaching or suggesting the reduction method and optimal stoichiometry for purity/yield, including the specified molar ratio of the hydrogenating agent). A PHOSITA would have been motivated to optimize the reduction conditions to improve yield and purity and to minimize side reactions, with a reasonable expectation of success given the teachings of Kondo's 1999 paper.
• Claims 7, 8, 9, and 10, directed to alternative processes for preparing intermediate compound (4), are also likely obvious over a combination of JP-A-4-154765 (for the known intermediate) and Torisawa 2000 (for a known method of preparation). A PHOSITA would be motivated to explore conventional synthetic transformations (oxidation, hydrolysis, reaction with oxalyl halide) to find improved or more efficient routes for known intermediates, given the existing knowledge of the compound's structure and its role in the synthesis of known active pharmaceutical ingredients.
• Claim 1 (process for preparing compound (1)) may also be obvious if the reaction of compound (2) with compound (3) in the presence of a carbonylating agent represents a conventional amide bond formation from known precursors. However, without more specific details from the cited prior art regarding this particular coupling, a definitive conclusion is more challenging. If the components (2) and (3) are known intermediates, and amide formation via carbonylation is a common synthetic strategy, a PHOSITA would have been motivated to combine these elements to form the known compound (1).

In summary, the key aspect of obviousness for US8273735 revolves around the optimization of known reactions and the application of standard synthetic methodologies to produce known compounds or intermediates, especially as affirmed by the Federal Circuit's finding on the reduction step (Claim 11) over Kondo's 1999 paper.

External Resources Cited:
US8273735B2 - Process for preparing benzazepine compounds or salts thereof - Google Patents. https://patents.google.com/patent/US8273735B2/en (Accessed 2026-05-22).

Patent Term and Related Applications for US Patent 8,273,735

US Patent 8,273,735 is an active patent currently assigned to Otsuka Pharmaceutical Co Ltd. The patent's status and family information are detailed below.

Patent Term Adjustment (PTA) and Patent Term Extension (PTE)

Specific Patent Term Adjustment (PTA) or Patent Term Extension (PTE) data for US8273735 is typically found directly on the USPTO Patent Center's patent record. However, the provided Google Patents link states an "Adjusted expiration" date. This implies that some form of adjustment (likely PTA) has been applied.

Continuation and Divisional Applications

The Google Patents page for US8273735B2 lists "Other versions" which can indicate related applications such as continuations or divisionals.

• US20090306369A1 is listed as another version. Given its publication number format and its earlier publication date (2009-12-10) compared to the granted patent's publication date (2012-09-25), it is an earlier publication of the same application (US12/064,178) that led to US8273735. It is not a separate continuation or divisional application but the published application that matured into US8273735.

Without direct access to the USPTO Patent Center's prosecution history for US8273735 or its application US12/064,178, it is not possible to definitively identify any continuing applications (continuation or divisional applications) filed from US12/064,178. A continuation application claims the same invention as a parent application and is filed while the parent is still pending. A divisional application arises from a restriction requirement by the USPTO, claiming a distinct invention disclosed in the parent but not claimed. Both types are entitled to the parent's priority date.

Related Family Members

The application number for US8273735 is US12/064,178, which has a filing date of September 1, 2006. Its priority date is September 2, 2005.

The Google Patents page for US8273735B2 itself serves as the primary family member for the granted patent. Other publications of this application, such as US20090306369A1, are part of the same patent family.

Projected Expiration Date

The "Adjusted expiration" date provided by Google Patents for US8273735B2 is August 14, 2028.

This expiration date is calculated based on the 20-year term from the earliest filing date (September 1, 2006, for application US12/064,178), plus any applicable patent term adjustments (PTA). Utility patents generally expire 20 years from their filing date, subject to extensions (PTE) or adjustments (PTA).## Patent Term and Related Applications for US Patent 8,273,735

Patent Term Adjustment (PTA) and Patent Term Extension (PTE)

While specific details of Patent Term Adjustment (PTA) or Patent Term Extension (PTE) are typically found in the USPTO Patent Center, the Google Patents entry for US8273735B2 explicitly indicates an "Adjusted expiration" date. This signifies that some form of adjustment to the patent term has been made.

Continuation Applications

US Patent 8,273,735 (application number US12/064,178) was published as US20090306369A1 on December 10, 2009. This is an earlier publication of the same application that eventually issued as US8273735B2, rather than a separate continuation application.

The provided information does not explicitly list any other continuation applications that might have been filed from the parent application US12/064,178. A continuation application is filed to pursue additional claims to the same invention disclosed in the parent application and must be filed while the parent application is still pending.

Divisional Applications

The provided patent information does not explicitly list any divisional applications filed from the parent application US12/064,178. A divisional application typically arises when the USPTO issues a restriction requirement, determining that a single application contains two or more independent and distinct inventions. The divisional application then claims a distinct invention disclosed but not claimed in the parent application and is entitled to the benefit of the filing date of the original application.

Related Family Members

The primary related family member explicitly identified in the provided context is the published application US20090306369A1, which is the publication of the application (US12/064,178) that matured into US8273735B2.

Projected Expiration Date

The projected expiration date for US Patent 8,273,735B2 is August 14, 2028. This date is typically calculated as 20 years from the earliest filing date (September 1, 2006, for application US12/064,178) plus any applicable Patent Term Adjustment (PTA) granted by the USPTO.

Defensive Disclosure: Process for Preparing Benzazepine Compounds and Related Intermediates

Publication Date: April 26, 2026

Authors: Senior Patent Strategist & Research Engineer, Defensive Publishing Team

This document outlines derivative process technologies related to the synthesis of benzazepine compounds and their intermediates, building upon the principles disclosed in US Patent 8,273,735. The aim is to establish prior art for various modifications, extensions, and applications, thereby limiting the scope for future incremental patenting by competitors. This disclosure focuses on variations of the core chemical processes rather than the therapeutic application of the final compounds.

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Derivatives of Independent Claim 1: Process for Preparing Benzazepine Compound (1)

(Reacting compound (2) with amide compound (3) in presence of a carbonylating agent)

1. Material & Component Substitution

Derivative 1.1: Heterogeneous Catalytic Carbonylation with Supported Precious Metals

• Enabling Description: The reaction of a benzazepine compound (2) with an aryl halide amide compound (3) to yield benzazepine compound (1) is performed via heterogeneous catalytic carbonylation. Instead of soluble metal carbonyls or palladium complexes, a heterogeneous catalyst comprising palladium nanoparticles (1-10 nm diameter) immobilized on a high-surface-area support such as activated carbon, silica gel, or mesoporous alumina is utilized. The reaction proceeds under a CO atmosphere (1-10 bar) at elevated temperatures (80-180° C.) in a solvent such as N,N-dimethylformamide or N-methylpyrrolidone, in the presence of a non-coordinating base (e.g., DBU or triethylamine). This allows for easier catalyst separation and recycling.

  graph TD
      A[Compound (2)] -->|React with CO| B(Supported Pd Catalyst)
      C[Amide Compound (3)] -->|Solvent, Base, Heat| B
      B --> D{Benzazepine Compound (1)}
      D --> E[Catalyst Separation]
      E --> F[Purification]
  

Derivative 1.2: Carbonylation via Photoredox Catalysis with Organic Dyes

• Enabling Description: The carbonylation reaction is mediated by an organic photoredox catalyst, such as Eosin Y or Rhodamine B, under visible light irradiation (400-550 nm LED source). Compound (2) and amide compound (3) are reacted in a polar aprotic solvent (e.g., acetonitrile, DMSO) under 1 atm of CO gas. A sacrificial electron donor (e.g., Hantzsch ester) and a mild base (e.g., potassium carbonate) are included. The photoredox catalyst generates a reactive species, facilitating the CO insertion and subsequent coupling, operating at ambient temperature.

  graph TD
      A[Compound (2)] -->|React| PC(Photoredox Catalyst + Light)
      C[Amide Compound (3)] -->|CO, Sacrificial Donor, Base| PC
      PC --> D{Benzazepine Compound (1)}
      D --> F[Purification]
  

Derivative 1.3: Supercritical CO2 as Solvent and Carbonylating Agent Precursor

• Enabling Description: The synthesis of benzazepine compound (1) from compound (2) and amide compound (3) is conducted in supercritical carbon dioxide (scCO2) as both the solvent and a source of carbonylating agent (via in situ generation of CO or direct reactivity under specific conditions, or simply leveraging its solvent properties for CO delivery). The reaction is run at pressures exceeding 73.8 bar and temperatures above 31.1° C., typically at 100-200 bar and 100-200° C., in the presence of a palladium-based catalyst system (e.g., Pd(OAc)2 with phosphine ligand) and a base. The tunable solvent properties of scCO2 allow for facile product separation by depressurization.

  graph TD
      A[Compound (2)] --> SC(scCO2 Environment)
      C[Amide Compound (3)] --> SC
      K[Pd Catalyst, Base] --> SC
      SC --> D{Benzazepine Compound (1)}
      D --> E[Depressurization Separation]
      E --> F[Purification]
  

2. Operational Parameter Expansion

Derivative 1.4: Microfluidic Flow Reactor for Continuous Carbonylation

• Enabling Description: The carbonylation reaction is implemented in a continuous flow microfluidic reactor system. Reactant solutions of compound (2), amide compound (3), catalyst (e.g., Pd(PPh3)4), and base are pumped through microchannels (100-500 µm internal diameter) at controlled flow rates, typically 10 µL/min to 10 mL/min. CO gas is precisely introduced into the flow, ensuring rapid mixing and efficient gas-liquid mass transfer. The reaction temperature (80-150° C.) and pressure (1-10 bar CO) are precisely maintained within the microreactor, leading to short residence times (minutes to hours) and improved selectivity compared to batch processes.

  graph LR
      A[Feed 1: Compound (2) + Catalyst] --> MFR(Microfluidic Reactor)
      B[Feed 2: Amide Compound (3) + Base] --> MFR
      C[CO Gas Inlet] --> MFR
      MFR --> D{Benzazepine Compound (1) Stream}
      D --> E[Downstream Processing]
  

Derivative 1.5: High-Pressure, Low-Temperature Carbonylation with Optimized Ligand

• Enabling Description: The carbonylation of compound (2) with amide compound (3) is conducted under high CO pressure (20-50 bar) but at moderate temperatures (30-70° C.) to suppress side reactions and enhance product stability. This is achieved by utilizing a highly active palladium catalyst system featuring electron-rich, sterically demanding ligands (e.g., N-heterocyclic carbenes, bulky phosphines like P(t-Bu)3 or SPhos). The reaction proceeds in an anhydrous solvent (e.g., THF, 1,4-dioxane) in the presence of an inorganic base (e.g., Cs2CO3). The high CO concentration shifts equilibrium, enabling lower temperatures while maintaining reaction rates.

  graph TD
      A[Compound (2)] --> R(High-Pressure Reactor)
      C[Amide Compound (3)] --> R
      K[Pd Catalyst + Bulky Ligand] --> R
      G[CO (20-50 bar)] --> R
      B[Base, Solvent] --> R
      R -->|30-70°C| D{Benzazepine Compound (1)}
      D --> F[Purification]
  

3. Cross-Domain Application

Derivative 1.6: Benzazepine Motif for Specialty Polymer Synthesis

• Enabling Description: The carbonylation process described in Claim 1 is adapted to synthesize benzazepine-containing monomers (e.g., Formula (1) where R1 or R2 contains a polymerizable functional group like an acrylate or epoxide). These monomers are then incorporated into specialty polymers, for instance, as a functional cross-linking agent in advanced adhesive formulations or as a UV-curable component in protective coatings. The benzazepine moiety, potentially with its specific electronic or steric properties, confers unique mechanical or optical properties to the resulting polymer matrix.

  graph TD
      A[Compound (2)-FG1] --> P(Polymer Synthesis)
      C[Amide Compound (3)-FG2] --> P
      K[Carbonylation Process] --> A1(Benzazepine Monomer)
      A1 -->|Polymerization Reaction| SP(Specialty Polymer)
      P --> SP
      subgraph Functional Groups (FG)
          FG1[Polymerizable Group 1]
          FG2[Polymerizable Group 2]
      end
  

Derivative 1.7: Agrochemical Active Intermediate Synthesis

• Enabling Description: The core carbonylation chemistry is applied to synthesize novel benzazepine derivatives as intermediates for agrochemical active ingredients. For example, a benzazepine compound (1) bearing specific halogen or alkyl substituents relevant to pesticidal activity is generated via the described carbonylation. This intermediate is then further functionalized (e.g., via Suzuki coupling, amidation, or alkylation) to produce final agrochemical products such as insecticides, fungicides, or herbicides with improved efficacy or environmental profiles.

  graph TD
      S[Starting Precursors] --> R1(Carbonylation Process)
      R1 --> I(Benzazepine Intermediate (1))
      I --> R2(Further Functionalization)
      R2 --> AG(Agrochemical Active Ingredient)
  

Derivative 1.8: Ligand Synthesis for Catalysis in Energy Applications

• Enabling Description: Benzazepine compounds (1) are synthesized with specific functional groups (e.g., phosphine, N-heterocyclic carbene precursors, pyridine) incorporated into R1 or R2. These modified benzazepine structures act as novel chiral or achiral ligands. The carbonylation process is optimized for efficiency and purity for this purpose. These benzazepine-derived ligands are then complexed with transition metals (e.g., Ru, Ir, Ni) and employed as catalysts in energy-related applications, such as hydrogen production/storage, CO2 reduction, or selective biomass conversion reactions.

  graph TD
      A[Compound (2)-LG_Precursor] --> C(Carbonylation Process)
      C[Amide Compound (3)] --> C
      C --> L(Benzazepine Ligand)
      L --> D(Metal Complexation)
      D --> CA(Catalyst for Energy Applications)
  

4. Integration with Emerging Tech

Derivative 1.9: AI-Driven Optimization of Carbonylation Parameters with IoT Sensors

• Enabling Description: The carbonylation reaction is conducted in a smart reactor equipped with IoT sensors that provide real-time data on temperature, pressure, reactant concentrations (via in situ FTIR or Raman spectroscopy), and CO uptake. This data is fed into an AI-driven optimization algorithm (e.g., Bayesian optimization or reinforcement learning) that adjusts reaction parameters (e.g., temperature profile, CO partial pressure, catalyst loading, reactant feed rates) in real-time to maximize yield and purity of benzazepine compound (1) while minimizing side product formation. A digital twin model of the reaction is used for predictive control.

  graph TD
      R(Smart Reactor) --> |Sensor Data| IoT[IoT Platform]
      IoT --> AI[AI Optimization Algorithm]
      AI --> |Control Signals| R
      R -- Reaction Progress --> RP(Real-time Analytics)
      RP --> |Yield, Purity| AI
      subgraph Parameters
          A[Temperature]
          B[Pressure]
          C[Concentration]
          D[CO Uptake]
      end
      R -- Measures --> A, B, C, D
  

Derivative 1.10: Blockchain for Catalyst Supply Chain Verification in GMP Synthesis

• Enabling Description: In the Good Manufacturing Practice (GMP) synthesis of benzazepine compound (1), the entire supply chain for the palladium catalyst and expensive phosphine ligands is immutably recorded on a blockchain. Each batch of catalyst, ligand, and starting material is assigned a unique cryptographic hash and tracked from raw material sourcing, through synthesis and purification, to delivery at the manufacturing facility. IoT sensors embedded in packaging record environmental conditions during transport. This provides an auditable, tamper-proof record of material provenance, purity, and storage conditions, ensuring regulatory compliance and preventing counterfeiting for high-value pharmaceutical intermediates.

  sequenceDiagram
      participant SM as Starting Material Supplier
      participant CS as Catalyst Supplier
      participant BL as Blockchain Ledger
      participant MF as Manufacturing Facility
      SM ->> BL: Record batch details (compound (2), (3))
      CS ->> BL: Record catalyst/ligand batch details
      MF ->> BL: Record IoT data (transport conditions)
      MF ->> BL: Record incoming quality control (QC) results
      MF ->> MF: Use verified materials in carbonylation
      MF ->> BL: Record in-process control (IPC) data for reaction
      BL -->> MF: Verify material provenance & quality
      BL -->> Auditor: Provide immutable audit trail
  

5. The "Inverse" or Failure Mode

Derivative 1.11: Controlled Partial Carbonylation for Library Synthesis

• Enabling Description: The carbonylation process is intentionally modified to achieve controlled incomplete conversion of compound (2) or amide compound (3), resulting in a reaction mixture rich in intermediates that are precursors to benzazepine compound (1) or novel side products. This is achieved by using sub-stoichiometric amounts of the carbonylating agent (CO) (e.g., 0.1-0.5 equivalents relative to the limiting reactant), reduced catalyst loading, or significantly shortened reaction times. The resulting partially converted mixtures are designed for direct screening in combinatorial libraries or for the synthesis of analogs with subtle structural differences, rather than for optimal yield of compound (1).

  graph TD
      A[Compound (2)] --> R(Reactor)
      C[Amide Compound (3)] --> R
      K[Low Catalyst] --> R
      G[Sub-Stoichiometric CO] --> R
      R --> I1(Unreacted (2))
      R --> I2(Unreacted (3))
      R --> I3(Partially Reacted Intermediates)
      R --> P(Low Yield Compound (1))
      I1, I2, I3, P --> L[Combinatorial Library]
  

Derivative 1.12: Low-Power, Rate-Limited Carbonylation for Kinetic Studies

• Enabling Description: The carbonylation process is executed under conditions deliberately chosen for low reaction rates and limited conversion, such as very low temperatures (e.g., -20 to 20° C.), minimal catalyst concentrations (e.g., 0.001-0.005 mol% Pd), and inert solvents that do not promote high reactivity. This "low-power" mode is specifically designed not for production, but for detailed kinetic and mechanistic investigations, allowing for the precise monitoring of intermediate formation, catalyst deactivation pathways, and energy profiles. The data collected facilitates a deeper understanding of the reaction mechanism without uncontrolled exothermic events.

  graph TD
      A[Compound (2)] --> R(Kinetic Study Reactor)
      C[Amide Compound (3)] --> R
      K[Minimial Catalyst] --> R
      G[Low Temperature, Pressure] --> R
      R --> S1(Sampling Port 1)
      R --> S2(Sampling Port 2)
      S1, S2 --> A(Analytical Instruments)
      A --> D[Kinetic Data]
  

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Derivatives of Independent Claims 7, 8, 9, 10: Processes for Preparing Benzoic Acid Compound (4)

(Various methods: Reacting (11) with oxalyl halide (19); Oxidizing (12); Hydrolyzing (13); Oxidizing (14))

1. Material & Component Substitution

Derivative 2.1: Enzymatic Oxidation of Amide Compound (12) or (14)

• Enabling Description: The oxidation of amide compound (12) or (14) (bearing an alkyl side chain convertible to a carboxylic acid) to benzoic acid compound (4) is performed using an enzymatic biocatalytic system. This could involve whole-cell fermentation with genetically engineered microorganisms expressing relevant monooxygenases or dioxygenases (e.g., cytochrome P450 enzymes) or purified enzyme preparations (e.g., alcohol oxidases, aldehyde dehydrogenases). The reaction is conducted in aqueous buffer systems at mild temperatures (25-45° C.) and physiological pH, offering high chemo-, regio-, and enantioselectivity, and reducing hazardous waste streams.

  graph TD
      A[Amide Compound (12) or (14)] --> B(Enzyme/Whole-Cell Bioreactor)
      B --> C{Benzoic Acid Compound (4)}
      C --> D[Enzyme/Biomass Separation]
      D --> E[Purification]
  

Derivative 2.2: Solid-Phase Reagent for Oxalyl Halide Reaction (Claim 7)

• Enabling Description: The reaction of amide compound (11) with an oxalyl halide (19) (e.g., oxalyl chloride) to yield benzoic acid compound (4) is carried out using a solid-phase equivalent of the activating agent. For instance, a polymer-supported reagent like a polymer-bound sulfonyl chloride or a polymer-bound phosphoryl chloride is employed to in situ activate the carboxylic acid derivative (e.g., from (11)) or facilitate the leaving group removal. This simplifies product isolation by filtration of the spent resin, avoiding the handling of corrosive liquid oxalyl halides and their byproducts.

  graph TD
      A[Amide Compound (11)] --> R(Reactor with Solid-Phase Reagent)
      B[Oxalyl Halide (19)] --> R
      R --> C{Benzoic Acid Compound (4)}
      C --> D[Filtration of Resin]
      D --> E[Purification]
  

Derivative 2.3: Ionic Liquid-Mediated Hydrolysis of Amide Compound (13) (Claim 9)

• Enabling Description: The hydrolysis of amide compound (13) to benzoic acid compound (4) is conducted in an ionic liquid (IL) solvent system. A protic ionic liquid (e.g., 1-butyl-3-methylimidazolium hydrogen sulfate) or a combination of a neutral ionic liquid with a dissolved acid/base catalyst (e.g., [BMIM][PF6] with p-toluenesulfonic acid or NaOH) is used. The reaction is performed at elevated temperatures (80-150° C.). Ionic liquids offer advantages such as non-volatility, high thermal stability, and recyclability, providing a greener alternative to traditional organic solvents for hydrolysis reactions.

  graph TD
      A[Amide Compound (13)] --> IL(Ionic Liquid Reactor)
      B[Water, Acid/Base Catalyst] --> IL
      IL --> C{Benzoic Acid Compound (4)}
      C --> D[IL Recycling]
      D --> E[Purification]
  

2. Operational Parameter Expansion

Derivative 2.4: Continuous Flow Electrochemical Oxidation of Amide Compound (12) or (14)

• Enabling Description: The oxidation of amide compound (12) or (14) to benzoic acid compound (4) is performed using a continuous flow electrochemical cell. The substrate solution (in an appropriate electrolyte and solvent, e.g., acetonitrile with supporting electrolyte like tetrabutylammonium perchlorate) is pumped through the cell, where an applied potential across working and counter electrodes drives the oxidation. The electrodes are fabricated from materials like glassy carbon or platinum. This offers precise control over redox potential, avoiding strong chemical oxidants, and enables safe scale-up by modularizing reactor units.

  graph LR
      A[Amide Compound (12) or (14) Feed] --> EF(Electrochemical Flow Cell)
      B[Electrolyte Feed] --> EF
      EF -->|Applied Potential| P(Product Stream)
      P --> D{Benzoic Acid Compound (4)}
      D --> E[Separation & Purification]
  

Derivative 2.5: Microwave-Assisted Hydrolysis of Amide Compound (13) (Claim 9)

• Enabling Description: The hydrolysis of amide compound (13) to benzoic acid compound (4) is significantly accelerated using microwave irradiation. The reaction mixture (compound (13), water, and acid or base catalyst) is subjected to microwave heating in a sealed reactor. This enables rapid heating to high temperatures (150-250° C.) and pressures, dramatically reducing reaction times from hours to minutes compared to conventional heating methods, improving throughput for industrial synthesis.

  graph TD
      A[Amide Compound (13)] --> MW(Microwave Reactor)
      B[Water, Acid/Base] --> MW
      MW -->|Rapid Heating| C{Benzoic Acid Compound (4)}
      C --> D[Cooling & Quenching]
      D --> E[Purification]
  

3. Cross-Domain Application

Derivative 2.6: Benzoic Acid Compound (4) for Advanced Pigment Synthesis

• Enabling Description: Benzoic acid compounds of Formula (4) are synthesized using the claimed processes (oxidation, hydrolysis, or oxalyl halide reaction) with specific R1/R2 groups that allow for chromophore integration. These derivatives are then used as key building blocks in the synthesis of advanced organic pigments, where the benzamide-benzoic acid scaffold provides a robust, color-fast core. Further functionalization (e.g., condensation with amines, dyes) transforms the compound into pigments for high-performance automotive coatings, textiles, or inkjet inks.

  graph TD
      S[Starting Materials (11,12,13,14)] --> P(Process (Claim 7,8,9,10))
      P --> I(Benzoic Acid Compound (4))
      I --> F(Further Functionalization to Chromophore)
      F --> AP(Advanced Organic Pigment)
  

Derivative 2.7: Intermediate for Biodegradable Polymer Chain Termination

• Enabling Description: Benzoic acid compounds (4) are synthesized (via any of the claimed processes) wherein the R1/R2 substituents are chosen to impart specific biodegradability or biocompatibility. These compounds are then employed as chain-transfer agents or chain-terminating agents in the controlled radical polymerization of biodegradable polymers (e.g., polyesters, polyamides), allowing for precise control over molecular weight and end-group functionality. This finds application in medical devices, sustainable packaging, or controlled-release drug delivery systems.

  graph TD
      SM[Starting Materials] --> Synth(Synthesis Process (Claim 7,8,9,10))
      Synth --> BAC(Benzoic Acid Compound (4))
      BAC --> P(Polymerization Reactor)
      P --> BDP(Biodegradable Polymer with Controlled End-Group)
  

Derivative 2.8: Surfactant Precursor in Enhanced Oil Recovery

• Enabling Description: Benzoic acid compounds (4) are modified (e.g., via esterification or amidation of the carboxylic acid, or functionalization of R1/R2) to create novel amphiphilic molecules. The benzoic acid moiety, synthesized by the claimed processes, serves as a hydrophobic backbone. These derivatives are then tested and optimized as surfactants in enhanced oil recovery (EOR) operations. They effectively lower interfacial tension between oil and water, mobilizing trapped oil in reservoir rock, thereby increasing oil production from mature fields.

  graph TD
      SM[Starting Materials] --> Synth(Synthesis Process (Claim 7,8,9,10))
      Synth --> BAC(Benzoic Acid Compound (4))
      BAC --> Mod(Amphiphilic Modification)
      Mod --> SUR(Novel Surfactant)
      SUR --> EOR(Enhanced Oil Recovery Application)
  

4. Integration with Emerging Tech

Derivative 2.9: AI-Driven Catalyst Discovery and Reaction Pathway Prediction

• Enabling Description: For the oxidation (Claims 8, 10) or hydrolysis (Claim 9) processes, an AI-driven platform is used for de novo catalyst discovery and reaction pathway prediction. Machine learning models, trained on large datasets of reaction outcomes, predict optimal enzymatic or chemical catalysts, solvent systems, and reaction conditions (temperature, pH, pressure) to maximize the yield and selectivity of benzoic acid compound (4). This includes predicting the most efficient precursor ((12), (13), or (14)) and avoiding undesired side reactions.

  graph TD
      D(Reaction Database) --> ML(Machine Learning Model)
      ML --> P(Catalyst/Pathway Prediction)
      P --> E(Experimental Validation)
      E --> D
      subgraph Input
          A[Amide Compounds (12,13,14)]
          B[Desired Product (4)]
          C[Constraints]
      end
      Input --> ML
  

Derivative 2.10: IoT-Monitored Continuous Flow Reactor for Process Control and Optimization

• Enabling Description: The synthesis of benzoic acid compound (4) via oxidation (Claims 8, 10) or hydrolysis (Claim 9) is performed in a continuous flow reactor equipped with an array of IoT sensors. These sensors monitor key process variables such as reactant flow rates, temperature, pressure, pH (for hydrolysis), redox potential (for oxidation), and in-line UV-Vis or HPLC analysis for real-time product/intermediate concentration. This data is transmitted to a central control system, which uses feedback loops and predictive analytics to maintain optimal operating conditions, ensure consistency, and detect deviations for immediate intervention.

  graph TD
      A[Reactant Feed] --> R(Continuous Flow Reactor)
      R --> |Sensors: Temp, pH, Redox, Conc.| IoT[IoT Monitoring Unit]
      IoT --> C(Control System)
      C --> |Adjustments| R
      R --> P{Benzoic Acid Compound (4) Output}
      subgraph Sensors
          S1[Flow Rate]
          S2[Temperature]
          S3[pH/Redox]
          S4[In-line Analytics]
      end
      R -- Monitored by --> S1, S2, S3, S4
  

5. The "Inverse" or Failure Mode

Derivative 2.11: Partial Hydrolysis/Oxidation for Diversified Intermediate Synthesis

• Enabling Description: The hydrolysis (Claim 9) or oxidation (Claims 8, 10) processes are intentionally modulated to achieve partial conversion, yielding a mixture of the target benzoic acid compound (4) along with partially hydrolyzed or oxidized intermediates (e.g., amides, aldehydes, alcohols). This is achieved by using sub-stoichiometric amounts of water or oxidant, reduced reaction times, or milder catalysts. The objective is to generate a diverse set of functionalized intermediates from a single synthetic run, which can then be selectively isolated and further elaborated into a broader range of derivatives than just compound (4).

  graph TD
      A[Amide Compound (12, 13, or 14)] --> R(Controlled Reaction)
      R --> P1(Partially Oxidized/Hydrolyzed)
      R --> P2(Side Products)
      R --> P3(Target Benzoic Acid (4))
      R --> P4(Unreacted Starting Material)
      P1, P2, P3, P4 --> D[Diverse Intermediate Pool]
  

Derivative 2.12: Energy-Efficient, Low-Yield Production of Benzoic Acid Compound (4)

• Enabling Description: A process for generating benzoic acid compound (4) is designed with primary emphasis on minimizing energy consumption, even if it results in significantly lower yields or purity initially. This involves operating the oxidation or hydrolysis reactions at ambient temperature and pressure, utilizing less potent or sub-stoichiometric catalysts, and avoiding energy-intensive purification steps. The resulting crude product, while low in yield and purity, is suitable for applications where high purity is not immediately critical (e.g., initial biological screening, material bulk synthesis where purification is deferred), demonstrating a trade-off for reduced energy footprint.

  graph TD
      A[Amide Compound (12, 13, or 14)] --> R(Low-Energy Reactor)
      R --> LYS(Low Yield/Purity Product (4))
      LYS --> S[Basic Screening]
      LYS --> BF[Bulk Functionalization]
      R -- Optimized for --> E[Low Energy Consumption]
  

---

Derivatives of Independent Claim 11: Process for Preparing 2,3,4,5-tetrahydro-1H-1-benzazepine Compound (10)

(Reducing benzazepine compound (1) with hydrogenating agent in 0.1 to 1 mole ratio)

1. Material & Component Substitution

Derivative 3.1: Bio-Reduction with Ketoreductase Enzymes

• Enabling Description: The reduction of benzazepine compound (1) (which presumably contains a ketone or imine that is reduced to a hydroxyl or amine in compound (10)) is catalyzed by isolated ketoreductase (KRED) enzymes or whole-cell biocatalysts (e.g., engineered yeast or bacteria). The reaction is performed in an aqueous buffer system (pH 6-8) at mild temperatures (20-40° C.) with a cofactor regeneration system (e.g., glucose dehydrogenase for NADPH regeneration). This provides high enantioselectivity for chiral centers in compound (10), minimizes dehalogenation, and avoids harsh chemical reducing agents. The stoichiometry of the KRED is catalytic, with the limiting factor being substrate concentration or cofactor turnover.

  graph TD
      A[Benzazepine Compound (1)] --> BR(Bioreactor with KRED/Whole Cells)
      B[Cofactor Regeneration System] --> BR
      BR --> C{2,3,4,5-tetrahydro-1H-1-benzazepine Compound (10)}
      C --> D[Enzyme/Cell Separation]
      D --> E[Purification]
  

Derivative 3.2: Transfer Hydrogenation with Formic Acid/Salts

• Enabling Description: The reduction of benzazepine compound (1) to compound (10) is achieved via catalytic transfer hydrogenation. Instead of direct H2 gas or metal hydrides, a hydrogen donor like formic acid, ammonium formate, or sodium formate is used in conjunction with a ruthenium or iridium catalyst (e.g., [RuCl2(p-cymene)]2 or [IrCp*Cl2]2 dimers with chiral diamine ligands). The reaction is conducted in a polar protic solvent (e.g., isopropanol, water) at temperatures from 50-100° C. This method avoids the need for specialized high-pressure hydrogenation equipment and offers a selective reduction pathway.

  graph TD
      A[Benzazepine Compound (1)] --> R(Transfer Hydrogenation Reactor)
      B[Formic Acid/Salt] --> R
      C[Ru/Ir Catalyst] --> R
      R --> D{2,3,4,5-tetrahydro-1H-1-benzazepine Compound (10)}
      D --> E[Purification]
  

Derivative 3.3: Boron Hydride Polymers as Solid-Supported Reducing Agents

• Enabling Description: The reduction of benzazepine compound (1) is performed using a polymeric reagent incorporating borohydride functionality, such as a poly(4-vinylpyridine)-supported borohydride complex. The insoluble polymer acts as a heterogeneous reducing agent, allowing for easy separation by filtration after the reaction. The stoichiometric ratio is maintained by controlling the loading of borohydride sites on the polymer. This facilitates workup and avoids the handling of pyrophoric or highly reactive soluble metal hydrides, enhancing process safety and scalability.

  graph TD
      A[Benzazepine Compound (1)] --> R(Reactor with Polymer-Supported Borohydride)
      R --> C{2,3,4,5-tetrahydro-1H-1-benzazepine Compound (10)}
      C --> D[Filtration of Polymer]
      D --> E[Purification]
  

2. Operational Parameter Expansion

Derivative 3.4: High-Throughput Microplate-Based Reduction Screening

• Enabling Description: The reduction of benzazepine compound (1) to compound (10) is optimized using a high-throughput screening platform in 96-well or 384-well microplates. Automated liquid handlers dispense small volumes (µL scale) of compound (1), various hydrogenating agents (LiAlH4, NaBH4, Zn(BH4)2, diborane precursors), catalysts, and solvents at varying molar ratios (0.1 to 1 equivalent, plus broader ranges to explore selectivity). Each well represents a unique reaction condition, allowing for rapid identification of optimal conditions (minimal dehalogenation, maximal yield, desired stereoselectivity) using robotic analytical techniques (e.g., plate-based HPLC-MS).

  graph TD
      S(Stock Solutions) --> L(Automated Liquid Handler)
      L --> MP(Microplate Reactor)
      MP --> A(Automated Analytics)
      A --> D[Data Analysis & Optimization]
      subgraph Variables
          V1[Hydrogenating Agent Type]
          V2[Molar Equivalent (0.1-1)]
          V3[Solvent]
          V4[Temperature]
      end
      MP -- Varies --> V1, V2, V3, V4
  

Derivative 3.5: Supercritical Hydrogenation (SuperH2) for Enhanced Selectivity

• Enabling Description: The reduction of benzazepine compound (1) to compound (10) is performed using supercritical hydrogen (SuperH2) as the reducing agent, in conjunction with a heterogeneous catalyst (e.g., Pt/C or Pd/C). Operating above the critical point of hydrogen (12.9 bar, -240° C.) at elevated temperatures (50-150° C.) and pressures (100-300 bar), SuperH2 exhibits enhanced solubility in organic substrates and improved mass transfer. This leads to higher reaction rates, reduced catalyst loading, and potentially greater selectivity in avoiding dehalogenation due to different kinetic profiles under supercritical conditions.

  graph TD
      A[Benzazepine Compound (1)] --> SHR(Supercritical Hydrogenation Reactor)
      B[H2 (Supercritical)] --> SHR
      C[Heterogeneous Catalyst] --> SHR
      SHR --> D{2,3,4,5-tetrahydro-1H-1-benzazepine Compound (10)}
      D --> E[Depressurization Separation]
      E --> F[Purification]
  

3. Cross-Domain Application

Derivative 3.6: Hydrogenation of Bio-Renewable Feedstocks for Fuels/Chemicals

• Enabling Description: The selective hydrogenation principles (0.1 to 1 mole ratio of hydrogenating agent to substrate) established for benzazepine compound (1) are directly applied to the reduction of specific functional groups in bio-renewable feedstocks (e.g., ketones, aldehydes, unsaturated bonds in lignin derivatives or bio-oils). This aims to produce platform chemicals, biofuels, or value-added biochemicals from sustainable sources, while minimizing over-reduction or side reactions that lead to undesirable byproducts. The precise control of reducing agent stoichiometry is critical to achieving specific product profiles.

  graph TD
      BRF[Bio-Renewable Feedstock] --> HR(Hydrogenation Reactor)
      HR -->|Controlled Reducing Agent (0.1-1 eq)| PC(Platform Chemicals/Biofuels)
      PC --> FV[Fuel/Chemical Valorization]
  

Derivative 3.7: Controlled Reduction in Polymer Degradation/Recycling

• Enabling Description: The controlled reduction methodology (using sub-stoichiometric hydrogenating agent amounts) is employed in processes for the selective chemical recycling or degradation of polymers. For instance, specific reducible linkages or functional groups within a polymer chain are targeted, while other groups are preserved. This allows for controlled depolymerization or modification, yielding valuable monomers or oligomers without completely destroying the polymer backbone, which can then be reused or reprocessed. The 0.1 to 1 mole ratio control prevents excessive degradation.

  graph TD
      PM[Polymer Material] --> CDR(Controlled Degradation/Reduction)
      CDR -->|0.1-1 eq Reducing Agent| OMO(Oligomers/Monomers)
      OMO --> RC[Recycling/Reprocessing]
  

Derivative 3.8: Fine Chemical Synthesis for OLED Materials

• Enabling Description: The reduction process described (Claim 11) is used to synthesize 2,3,4,5-tetrahydro-1H-1-benzazepine compounds (10) where the R1, R2, or X1 substituents are modified to incorporate chromophoric or emissive properties, making them suitable as building blocks for organic light-emitting diode (OLED) materials. The high purity and selective reduction achieved by the specified molar ratio of hydrogenating agent are critical to ensure the desired electronic properties and minimize defects in the final OLED device, which are sensitive to impurities.

  graph TD
      BC[Benzazepine Compound (1) - OLED Precursor] --> R(Reduction Process (Claim 11))
      R --> THC[2,3,4,5-tetrahydro-1H-1-benzazepine (10) - OLED Building Block]
      THC --> OLEDM[OLED Material Synthesis]
      OLEDM --> OLEDD[OLED Device Fabrication]
  

4. Integration with Emerging Tech

Derivative 3.9: AI-Predicted Solvent/Hydride Combinations and IoT Monitoring

• Enabling Description: An AI model (e.g., using Quantitative Structure-Property Relationships (QSPR) and machine learning) is developed to predict the optimal solvent system and specific combination of hydrogenating agent (e.g., NaBH4 variants, LiAlH4) to achieve the highest yield and minimal dehalogenation in the reduction of benzazepine compound (1). This prediction is based on the specific substituents R1, R2, and X1. The reaction is monitored by IoT sensors providing real-time spectroscopic data (e.g., NIR for hydride consumption, Raman for product/impurity formation), feeding back to the AI for adaptive adjustments to maintain optimal conditions.

  graph TD
      D(Reaction Data, Compound Structures) --> AI[AI Predictive Model]
      AI --> P(Optimal Solvent/Hydride Prediction)
      R(Reactor) --> |IoT Sensor Data| IOT[IoT Platform]
      IOT --> C(Control System)
      C --> |Adaptive Adjustments| R
      P --> R
      R -- Yield, Purity --> F[Feedback to AI]
  

Derivative 3.10: Blockchain for Traceability of Deuterated Reducing Agents for Metabolite Synthesis

• Enabling Description: In the synthesis of selectively deuterated analogs of compound (10) for pharmacokinetic studies or as internal standards in quantitative analysis, the provenance and purity of deuterated hydrogenating agents (e.g., NaBD4, LiAlD4, D2-gas) are tracked using a blockchain. Each batch of deuterated reagent, from isotopic enrichment to delivery, has its isotopic purity, synthesis route, and storage conditions immutably recorded. This blockchain ledger ensures forensic-level traceability and authenticity, critical for regulatory compliance and the reliability of analytical methods that rely on deuterated standards.

  sequenceDiagram
      participant IRA as Isotopic Reagent Supplier
      participant BL as Blockchain Ledger
      participant R&D as R&D Lab (Metabolite Synthesis)
      IRA ->> BL: Record deuterated reagent batch details (purity, origin)
      BL -->> R&D: Provide immutable certificate of analysis
      R&D ->> R&D: Use verified deuterated reagents for reduction
      R&D ->> BL: Record reaction parameters & analytical results (MS, NMR)
      BL -->> Auditor: Enable comprehensive audit of deuterated standard production
  

5. The "Inverse" or Failure Mode

Derivative 3.11: Partial Reduction for Synthesis of Novel Precursors

• Enabling Description: The reduction process of benzazepine compound (1) (e.g., a ketone) is designed to halt at an intermediate stage, yielding a partially reduced product (e.g., a hemiacetal or a less-reduced alcohol) rather than the fully reduced compound (10). This is achieved by precise control of the hydrogenating agent stoichiometry (e.g., 0.05-0.1 equivalents, or using a very weak reducing agent), short reaction times, or temperature quenching. The partially reduced compound serves as a novel precursor for further derivatization, allowing access to a wider chemical space of benzazepine scaffolds than just compound (10).

  graph TD
      A[Benzazepine Compound (1) (Ketone)] --> R(Controlled Reduction)
      R --> PR(Partially Reduced Product)
      PR --> F[Further Functionalization]
      F --> NBP(Novel Benzazepine Products)
      R -- Conditions --> S[Sub-stoichiometric Reductant, Short Time]
  

Derivative 3.12: Slow, Non-Selective Reduction for Degradation Studies

• Enabling Description: The reduction of benzazepine compound (1) is intentionally performed under conditions that lead to slow reaction rates and poor selectivity, primarily for studying degradation pathways or the long-term stability of the molecule under reductive stress. This involves using highly diluted reagents, weak reducing agents (e.g., catalytic H2/Pd in presence of mild poisoning agents, or a very dilute NaBH4 solution at low temperature), or highly unoptimized solvents. The "failure" here is a lack of high yield/purity, but the goal is to observe and characterize all possible degradation and side-reaction products, including dehalogenation products, to understand compound stability and impurity profiles.

  graph TD
      A[Benzazepine Compound (1)] --> R(Degradation Study Reactor)
      R --> |Weak/Dilute Reductant| SP1(Dehalogenated Product)
      R --> SP2(Over-reduced Product)
      R --> SP3(Other Side Products)
      R --> PR(Poor Yield Target Product (10))
      SP1, SP2, SP3, PR --> A(Analytical Characterization)
      A --> D[Degradation Pathway Data]
  

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Combination Prior Art Scenarios with Open-Source Standards

Here are at least three scenarios where the processes disclosed in US Patent 8,273,735, and their derivatives, could be combined with existing open-source standards to establish further prior art.

1. Integration with Open-Source Cheminformatics for Reaction Design & Optimization

• Scenario: The processes for synthesizing benzazepine compounds (1) (Claim 1), benzoic acid compounds (4) (Claims 7-10), and tetrahydro-benzazepine compounds (10) (Claim 11) are implemented and optimized using an open-source cheminformatics platform.
• Enabling Description: Reaction conditions (solvents, catalysts, temperatures, reactant ratios like the 0.1-1 mole for reduction in Claim 11) for all claimed processes are modeled and predicted using open-source cheminformatics toolkits such as RDKit or OpenBabel. For example, RDKit's reaction functionality is used to enumerate possible reactants and products, predict reaction outcomes, and calculate molecular descriptors. These descriptors are then fed into open-source machine learning libraries (e.g., Scikit-learn) to build predictive models for yield, purity, and byproduct formation based on experimental data. Furthermore, automated retrosynthesis algorithms (e.g., those implemented in AiZynthFinder, an open-source tool) are used to explore alternative synthetic routes for compounds (1), (4), and (10), making any future claims on minor variations of known synthetic strategies obvious. This entire workflow, including data handling and visualization, adheres to open-source data exchange formats like SMILES and InChI strings for chemical structures.

  graph TD
      A[Claimed Reaction Steps] --> RDKit[RDKit for Reaction Modeling]
      D[Experimental Data] --> SKL[Scikit-learn for Predictive Models]
      RDKit --> SKL
      SKL --> O[Optimized Reaction Parameters]
      O --> E[Execute Reaction]
      AiZF[AiZynthFinder for Retrosynthesis] --> A
      subgraph Open-Source Tools
          RDKit
          SKL
          AiZF
      end
  

2. Open-Source Electronic Laboratory Notebook (ELN) for Process Documentation

• Scenario: All experimental procedures, raw data, and analytical results generated during the development and execution of the processes claimed in US8273735 are meticulously documented within an open-source Electronic Laboratory Notebook (ELN) system.
• Enabling Description: Researchers utilize an open-source ELN platform, such as OS-ELN (Open Source Electronic Lab Notebook) or a custom ELN built using open-source web frameworks (e.g., Django or Flask). This system captures every detail of the chemical reactions, including exact reagent quantities (especially the critical 0.1 to 1 mole ratio for the hydrogenating agent in Claim 11), solvent volumes, reaction temperatures, stirring rates, catalyst batch numbers, and purification protocols. Analytical data from instruments (e.g., NMR, HPLC, MS) are automatically imported and timestamped, ensuring data integrity. The ELN adheres to open data formats (e.g., JSON, XML) for experiment descriptions and JCAMP-DX for spectroscopic data, facilitating interoperability and public sharing of methods. This comprehensive, publicly available record of detailed experimental conditions for preparing compounds (1), (4), and (10) makes it difficult to patent minor procedural variations.

  graph TD
      Exp[Chemical Experiment (Claim 1, 7-11)] --> ELN[Open-Source ELN (e.g., OS-ELN)]
      Anal[Analytical Instruments (HPLC, NMR, MS)] --> ELN
      ELN --> |Timestamped Records| DB(Open-Source Database)
      DB --> |JSON/XML Export| Public[Public Data Repository]
      subgraph Open-Source Standards
          ELN
          DB
          Public
      end
  

3. Automated Synthesis and Optimization with Open-Source Robotics Platform

• Scenario: The high-throughput experimentation and scale-up of the claimed chemical processes are performed using an open-source robotics and automation platform, making variations in reaction conditions readily reproducible and published.
• Enabling Description: The synthesis of benzazepine and benzoic acid compounds (1, 4, 10) is automated using a liquid handling robot controlled by an open-source operating system and software (e.g., OpenTrons Python API or a custom robotic platform utilizing ROS - Robot Operating System). This system precisely executes multi-step syntheses, including reagent addition, mixing, heating (controlled by open-source PID controllers), and sampling. Automated parameter sweeps are performed for key variables, such as the molar ratio of hydrogenating agent in Claim 11, the type of carbonylating agent in Claim 1, or different oxidizing/hydrolyzing agents in Claims 7-10. Reaction vessels are monitored by low-cost, open-source sensors (e.g., Arduino or Raspberry Pi based temperature/pH probes). All robotic scripts, experimental protocols, and results are published in an open-access repository, providing a detailed and executable record of diverse process conditions.

  graph TD
      R[Chemical Reagents] --> LHR(Liquid Handling Robot)
      LHR --> WS[Automated Workstation]
      WS --> |Open-Source Sensors| OS_MCU[Open-Source Microcontroller]
      OS_MCU --> ROS[ROS / OpenTrons API]
      ROS --> LHR
      WS -- Synthesizes --> Prod[Compounds (1), (4), (10)]
      Prod --> Pub[Open-Access Repository]
      subgraph Open-Source Platform
          ROS
          LHR
          OS_MCU
      end