US 8501730

US Patent 8501730, titled "Process for preparing benzazepine compounds or salts thereof," was issued to Otsuka Pharmaceutical Co Ltd.. The patent was filed on May 17, 2012, and granted on August 6, 2013. The inventors listed are Yasuhiro Torisawa, Kaoru Abe, Yasuaki Muguruma, Shigekazu Fujita, Hidenori Ogawa, Naoto Utsumi, and Masahiro Miyake.

Abstract Overview:
The invention provides a method for preparing benzazepine compounds of formula (1) and intermediate benzoic acid compounds of formula (4) with high yield and purity on an industrial scale. These compounds are valuable as intermediates for creating pharmaceutically active 2,3,4,5-tetrahydro-1H-1-benzazepine compounds, which act as vasopressin antagonists.

Plain-Language Overview of Independent Claims:

• Claim 1: This claim covers a process for making a specific type of benzazepine compound (formula 1) or its salts. The process involves reacting a benzazepine compound (formula 2) with an amide compound (formula 3) in the presence of a carbonylating agent. In these compounds, X1 and X2 are halogen atoms, and R1 and R2 are lower alkyl groups.
• Claim 2: This claim describes a process for producing a benzoic acid compound (formula 4) or its salts. This process involves reacting an amide compound (formula 11) with an oxalyl halide compound (formula 19), where X6 and X7 are independently halogen atoms. R1 and R2 are lower alkyl groups.
• Claim 3: This claim outlines a process for obtaining a benzoic acid compound (formula 4) or its salts by oxidizing an amide compound (formula 12) or its salts. X3 is a halogen atom, and R1 and R2 are lower alkyl groups.
• Claim 4: This claim details a process for producing a benzoic acid compound (formula 4) or its salts through the hydrolysis of an amide compound (formula 13) or its salts. X3 is a halogen atom, and R1 and R2 are lower alkyl groups.
• Claim 5: This claim covers a process for producing a benzoic acid compound (formula 4) or its salts by oxidizing an amide compound (formula 14) or its salts. R1 and R2 are lower alkyl groups.
• Claim 6: This claim describes a process for producing a 2,3,4,5-tetrahydro-1H-1-benzazepine compound (formula 10) or its salts. This is achieved by reducing a benzazepine compound (formula 1) or its salt using a hydrogenating agent. The crucial aspect is that the hydrogenating agent is used in a specific amount: between 0.1 to 1 mole per 1 mole of compound (1). R1 and R2 are lower alkyl groups, and X1 is a halogen atom.

Litigation Information (CAFC 2026 Dockets):
As of May 21, 2026, US Patent 8501730 has been involved in litigation at the Court of Appeals for the Federal Circuit. In the nonprecedential case Otsuka Pharmaceutical Co. v. Lupin Ltd. (No. 24-2297), the Federal Circuit affirmed a lower court's judgment that Lupin's tolvaptan ANDA process does not infringe US Patent 8501730. Additionally, the asserted method claims of the patent were found invalid as obvious over a 1999 synthesis paper by Kondo.

US Patent 8501730 has been involved in several litigation cases. Here is a summary of the known litigation:

1. Otsuka Pharmaceutical Co., Ltd. v. Lupin Ltd. and Lupin Pharmaceuticals, Inc.

   • Plaintiff(s): Otsuka Pharmaceutical Co., Ltd.
   • Defendant(s): Lupin Ltd. and Lupin Pharmaceuticals, Inc.
   • Jurisdiction: Court of Appeals for the Federal Circuit (CAFC) (Case No. 24-2297) and U.S. District Court for the District of Delaware (Civ. No. 21-900-RGA)
   • Filing Date: The appeal to the CAFC was docketed on September 10, 2024. The District Court case was filed in 2021.
   • Outcome/Current Status:
     • CAFC (24-2297): On May 21, 2026, a Federal Circuit panel affirmed the lower court's judgment. It was determined that Lupin's tolvaptan ANDA process does not infringe US Patent 8501730 and that the asserted method claims of the patent are invalid as obvious over a 1999 synthesis paper by Kondo.
     • District of Delaware (21-900-RGA): The District Court found that Lupin did not infringe the patents-in-suit. While the asserted claims of a related patent (US8273735) were found obvious, the asserted claims of US Patent 8501730 were found not invalid by the District Court. This decision was published on July 31, 2024.

2. Otsuka Pharmaceutical Co. Ltd. v. Par Pharmaceutical Inc.

   • Plaintiff(s): Otsuka Pharmaceutical Co. Ltd.
   • Defendant(s): Par Pharmaceutical Inc.
   • Jurisdiction: District of Delaware
   • Case Number: 1:13-cv-01979
   • Filing Date: November 26, 2013.
   • Outcome/Current Status: The outcome of this specific case is not explicitly detailed in the provided information, but Par Pharmaceutical has been involved in other patent litigation with Takeda Pharmaceutical Company Ltd. in an antitrust suit regarding generic Amitiza.

3. Otsuka Pharmaceutical Co., Ltd. v. Hetero USA Inc. et al.

   • Plaintiff(s): Otsuka Pharmaceutical Co., Ltd.
   • Defendant(s): Hetero USA Inc., Hetero Labs Ltd. Unit V, Hetero Labs Limited
   • Jurisdiction: District of Delaware
   • Case Number: 1:14-cv-00421
   • Filing Date: April 4, 2014.
   • Outcome/Current Status: The outcome of this case is not explicitly detailed in the provided information.

It is worth noting that Google Patents also lists several other cases filed in the Delaware District Court related to US Patent 8501730, though specific details like plaintiffs, defendants, and outcomes are not provided for all of them within the available data:

• 1:15-cv-00109
• 1:18-cv-00972
• 1:26-cv-00181
• 1:25-cv-00318
• 1:24-cv-00740
• 1:14-cv-00789
• 1:23-cv-00710
• 1:22-cv-00513
• 1:22-cv-00316

Proceedings overview

There are no AIA trial proceedings for US Patent 8501730 on file according to the USPTO ODP API.

Strategic summary

No PTAB proceedings have been filed against US Patent 8501730 according to the provided information. Therefore, all claims (1-6) of the patent remain untested in an AIA trial. This means there is no estoppel landscape established by prior PTAB decisions, and all prior-art grounds remain available for a defendant to challenge in a new proceeding. The absence of PTAB activity could suggest various things, such as the patent not being widely asserted or the asserted claims being considered robust against common invalidity challenges.

Recommended next steps

Since there is no PTAB activity on file for US Patent 8501730, a defendant currently facing assertion of this patent should consider initiating an AIA trial (Inter Partes Review or Post-Grant Review, depending on applicability) to challenge the patentability of the asserted claims. This would allow for a review of the patent's claims based on prior art and potentially lead to their invalidation, strengthening the defendant's position.

Inventors

• Yasuhiro Torisawa (Otsuka Pharmaceutical Co Ltd.)
• Kaoru Abe (Otsuka Pharmaceutical Co Ltd.)
• Yasuaki Muguruma (Otsuka Pharmaceutical Co Ltd.)
• Shigekazu Fujita (Otsuka Pharmaceutical Co Ltd.)
• Hidenori Ogawa (Otsuka Pharmaceutical Co Ltd.)
• Naoto Utsumi (Otsuka Pharmaceutical Co Ltd.)
• Masahiro Miyake (Otsuka Pharmaceutical Co Ltd.)

No unusual patterns observed, as all inventors appear to be employed by the original assignee at the time of filing.

Original assignee

Otsuka Pharmaceutical Co Ltd. is the original assignee named on the issued patent. Otsuka Pharmaceutical Co. Ltd. is a global pharmaceutical company that develops and markets a range of products, including pharmaceuticals for psychiatric, neurological, cardiovascular, and gastrointestinal diseases. One of their well-known products is tolvaptan (brand name Samsca, Jynarque), which is a vasopressin antagonist. The patent US8501730 is for a process to prepare intermediates for a vasopressin antagonist, suggesting a direct link to their product line. Otsuka Pharmaceutical Co Ltd. is currently operating.

Assignment timeline

The USPTO Patent Assignment Search at https://assignmentcenter.uspto.gov/ shows no assignment records for US8501730.

Timeline diagram

timeline
    title Ownership of US 8501730
    2012 : Filed by Otsuka Pharmaceutical Co Ltd
    2013 : Issued to Otsuka Pharmaceutical Co Ltd

NPE / troll-pattern signals

1. Shell-entity transfer — not present
2. Known asserter in the chain — not present
3. Repeat correspondent across the chain — not present
4. Cascading transfers — not present
5. Pre-litigation transfer — not present
6. Bankruptcy fire-sale — not present
7. Privateering — not present
8. Defensive aggregator (anti-NPE) — not present

Verdict

Operating-company assertion
Based on the available information, the patent appears to be owned by the original assignee, Otsuka Pharmaceutical Co Ltd., which is an operating company with products in the pharmaceutical sector. There are no recorded assignments of this patent, indicating that it remains with the original developer and manufacturer. This suggests the patent is likely used for defending their market position or asserting against direct competitors, as evidenced by the litigation history where Otsuka Pharmaceutical Co. v. Lupin Ltd. was a case.

For verification, see the USPTO Assignment Center search for US8501730: https://assignmentcenter.uspto.gov/

The most relevant prior art for US Patent 8501730, based on its citations and background discussion, includes several US patents and non-patent literature. The patent US8501730 has a priority date of September 2, 2005. References published or effectively filed before this date are relevant for potential anticipation under 35 U.S.C. § 102.

Here is an analysis of the cited prior art:

Patent Citations

1. US 6,468,988 B1

   • Full Citation: US 6,468,988 B1, "Process for preparing benzazepine compounds," Otsuka Pharmaceutical Co., Ltd., published October 22, 2002.
   • Publication/Filing Date: Publication date: October 22, 2002.
   • Brief Description: Based on the title, this patent likely discloses methods for synthesizing benzazepine compounds. Given the common assignee (Otsuka Pharmaceutical Co., Ltd.) and the subject matter, it is expected to detail processes relevant to the core structures found in US8501730.
   • Potential Anticipation: This reference potentially anticipates aspects of the processes described in Claims 1-6 of US8501730, particularly if it outlines general synthetic routes for benzazepine compounds or specific steps for making intermediates such as compounds (2), (3), (4), or (11)-(14).

2. US 6,262,077 B1

   • Full Citation: US 6,262,077 B1, "Benzazepine derivatives and their use as vasopressin antagonists," Otsuka Pharmaceutical Co., Ltd., published July 17, 2001.
   • Publication/Filing Date: Publication date: July 17, 2001.
   • Brief Description: The title suggests that this patent describes benzazepine derivatives that function as vasopressin antagonists. These compounds are highly likely to include the active pharmaceutical ingredient (compound 10 in US8501730) or closely related structures, and potentially its precursors like compound (1).
   • Potential Anticipation: This patent potentially anticipates the compound (10) itself and its utility as a vasopressin antagonist. If it also details a method for its preparation, it could anticipate Claim 6 (process for producing compound (10)). If it discloses the synthesis of compound (1), it could anticipate Claim 1.

3. US 2003/0060481 A1

   • Full Citation: US 2003/0060481 A1, "Novel production method for benzazepine compound," Otsuka Pharmaceutical Co., Ltd., published March 27, 2003.
   • Publication/Filing Date: Publication date: March 27, 2003.
   • Brief Description: The title indicates that this application describes a novel method for producing benzazepine compounds, implying relevance to the synthetic chemistry of these structures.
   • Potential Anticipation: It potentially anticipates method claims 1-6 if its disclosed "novel production method" includes the specific steps or conditions claimed in US8501730 for preparing compounds (1), (4), or (10), or their intermediates.

4. US 2004/0058930 A1

   • Full Citation: US 2004/0058930 A1, "Process for preparing benzazepine compounds or salts thereof," Otsuka Pharmaceutical Co., Ltd., published March 25, 2004.
   • Publication/Filing Date: Publication date: March 25, 2004.
   • Brief Description: This patent application, similar to others from the same assignee, focuses on a process for synthesizing benzazepine compounds or their salts.
   • Potential Anticipation: It potentially anticipates method claims 1-6 if the processes for preparing compounds (1), (4), or (10) or their intermediates, as claimed in US8501730, are disclosed in this document.

5. US 2005/0143397 A1

   • Full Citation: US 2005/0143397 A1, "Process for preparing benzazepine compounds or salts thereof," Otsuka Pharmaceutical Co., Ltd., published June 30, 2005.
   • Publication/Filing Date: Publication date: June 30, 2005.
   • Brief Description: This application describes a process for preparing benzazepine compounds or their salts, indicating its relevance to the synthesis of these compounds.
   • Potential Anticipation: It potentially anticipates method claims 1-6 if the specific reactions or conditions claimed in US8501730 are disclosed in this document.

6. US 2005/0203117 A1

   • Full Citation: US 2005/0203117 A1, "Process for preparing benzazepine compounds or salts thereof," Otsuka Pharmaceutical Co., Ltd., published September 15, 2005.
   • Publication/Filing Date: Publication date: September 15, 2005. This publication date is after the priority date of US8501730 (September 2, 2005). Therefore, it would only constitute prior art under 35 U.S.C. § 102 if its effective filing date (e.g., through a priority claim to an earlier application) precedes September 2, 2005. Without further information on its filing date or priority chain, its direct anticipatory effect based on publication date is limited.
   • Potential Anticipation: If its effective filing date is prior to September 2, 2005, this reference would likely disclose processes for preparing benzazepine compounds, potentially anticipating claims 1-6.

7. US 2006/0009633 A1

   • Full Citation: US 2006/0009633 A1, "Process for preparing benzazepine compounds or salts thereof," Otsuka Pharmaceutical Co., Ltd., published January 12, 2006.
   • Publication/Filing Date: Publication date: January 12, 2006. This publication date is after the priority date of US8501730 (September 2, 2005). Therefore, it would only constitute prior art under 35 U.S.C. § 102 if its effective filing date precedes September 2, 2005.
   • Potential Anticipation: If its effective filing date is prior to September 2, 2005, this reference would likely disclose processes for preparing benzazepine compounds, potentially anticipating claims 1-6.

8. US 2007/0197775 A1

   • Full Citation: US 2007/0197775 A1, "Production method for 7-chloro-2,3,4,5-tetrahydro-1H-1-benzazepine-5-one," Otsuka Pharmaceutical Co., Ltd., published August 23, 2007.
   • Publication/Filing Date: Publication date: August 23, 2007. This publication date is after the priority date of US8501730 (September 2, 2005). Therefore, it would only constitute prior art under 35 U.S.C. § 102 if its effective filing date precedes September 2, 2005.
   • Brief Description: The title specifies a production method for 7-chloro-2,3,4,5-tetrahydro-1H-1-benzazepin-5-one, which corresponds to compound (2) in US8501730.
   • Potential Anticipation: If its effective filing date is prior to September 2, 2005, this reference could anticipate the process for producing compound (2), which is a starting material for Claim 1 of US8501730.

Non-Patent Literature

1. Yasuhiro Torisawa et al., Bioorganic & Medicinal Chemistry Letters, 10 (2000), pp. 2493-2495.

   • Full Citation: Yasuhiro Torisawa et al., "A Novel and Efficient Synthesis of 7-Chloro-2,3,4,5-tetrahydro-1H-1-benzazepin-5-one," Bioorganic & Medicinal Chemistry Letters, 10 (2000), pp. 2493-2495.
   • Publication/Filing Date: Published in 2000. (Well before the September 2, 2005, prior art date of US8501730).
   • Brief Description: This article details a novel and efficient synthesis for 7-chloro-2,3,4,5-tetrahydro-1H-1-benzazepin-5-one. US8501730 explicitly cites this paper in its background art as a process for preparing benzoic acid compounds (4) via Reaction Scheme C.
   • Potential Anticipation: Since US8501730 states that "the benzoic acid compounds (4) are usually prepared by a process as shown in the following Reaction Scheme C (cf. Yasuhiro Torisawa et al., Bioorganic & Medicinal Chemistry Letters, 10(2000), pp. 2493-2495)", this paper potentially anticipates claims 2, 3, 4, or 5 of US8501730 if the disclosed process in the paper for preparing compound (4) (or its intermediates) directly matches the claimed processes. The synthesis of compound (2) (7-chloro-2,3,4,5-tetrahydro-1H-1-benzazepin-5-one) is also directly disclosed.

2. Kondo, Kazumi et al., Bioorganic & Medicinal Chemistry 7 (1999), pp. 1743-1754.

   • Full Citation: Kondo, Kazumi et al., "Synthetic Studies on Vasopressin V2 Receptor Antagonists: Asymmetric Synthesis of the Benzazepine Moiety," Bioorganic & Medicinal Chemistry, 7 (1999), pp. 1743-1754.
   • Publication/Filing Date: Published in 1999. (Well before the September 2, 2005, prior art date of US8501730).
   • Brief Description: This article presents synthetic studies on vasopressin V2 receptor antagonists, focusing on the asymmetric synthesis of the benzazepine moiety. US8501730 references this paper in its background art for the preparation of benzazepine compounds (1) using processes shown in Reaction Schemes A and B.
   • Potential Anticipation: US8501730 clearly indicates that "the benzazepine compounds (1) have been prepared by the processes as shown in the following Reaction schemes A and B (cf. JP-A-4-154765 and Kazumi Kondo et al., Bioorganic & Medicinal Chemistry 7(1999), pp. 1743-1754)." This directly implies that processes for preparing compound (1) and potentially compound (10) were known from this reference. Therefore, this paper could potentially anticipate Claim 1 (process for compound (1)) and Claim 6 (process for compound (10)) of US8501730. Prior litigation has already affirmed that "the asserted method claims of the patent were found invalid as obvious over a 1999 synthesis paper by Kondo," indicating its strong relevance to the method claims.

3. JP-A-4-154765

   • Full Citation: JP-A-4-154765 (Japanese Patent Application Publication).
   • Publication/Filing Date: Published in 1992 (Heisei 4). (Well before the September 2, 2005, prior art date of US8501730).
   • Brief Description: US8501730 states that compounds (1) and (4) are useful intermediates for preparing pharmaceutically active benzazepine compounds having vasopressin antagonistic activity (e.g., compound 10), citing JP-A-4-154765. It also indicates that known processes for preparing compound (1) are disclosed in this reference (Reaction Schemes A and B).
   • Potential Anticipation: This Japanese patent likely discloses the compounds (1), (4), and (10) themselves, and their use as vasopressin antagonists or intermediates. Crucially, it also describes processes for preparing compound (1) and compound (4). Therefore, this reference potentially anticipates Claims 1, 2, 3, 4, 5, and 6, as it appears to disclose the fundamental chemical transformations and the resulting compounds, albeit possibly without the "high yield and high purity on industrial scale" benefits claimed by US8501730.

Obviousness Analysis under 35 U.S.C. § 103

This analysis will focus on combinations of prior art that would render the independent claims of US Patent 8501730 obvious to a person having ordinary skill in the art (POSA) as of the priority date of September 2, 2005.

The core of the invention lies in providing improved processes for preparing benzazepine compounds (1), benzoic acid compounds (4), and the pharmaceutically active vasopressin antagonist compounds (10) in high yield and purity on an industrial scale. The patent explicitly states that existing methods for compounds (1) and (4) were not suitable for industrial production due to low yield, low purity, or difficulty in obtaining starting materials.

Motivation to Combine Prior Art

A POSA in the field of pharmaceutical organic chemistry would be motivated to combine known chemical reactions and processes to achieve more efficient, higher-yielding, and purer synthetic routes for pharmaceutically relevant compounds, particularly when existing methods are acknowledged as being industrially unsuitable. The patent itself highlights the problems with prior art processes, creating a clear motivation for improvement.

Obviousness Combinations

Combination 1: JP-A-4-154765 and Kazumi Kondo et al. (1999) rendering Claim 1 obvious.

• Prior Art:

  • JP-A-4-154765: This patent is explicitly cited in US8501730 as disclosing that benzazepine compounds of formula (1) are useful intermediates for preparing pharmaceutically active benzazepine compounds with vasopressin antagonistic activity, specifically compounds (10). It also discloses methods for preparing compounds (1) via Reaction Schemes A and B, although US8501730 states these methods are not suitable for industrial scale due to issues with yield and purity or difficulty in obtaining starting materials.
  • Kazumi Kondo et al., Bioorganic & Medicinal Chemistry 7 (1999), pp. 1743-1754: This publication is also explicitly cited in US8501730 as disclosing a method for preparing benzazepine compounds (1) (Reaction Scheme B).
  • Yasuhiro Torisawa et al., Bioorganic & Medicinal Chemistry Letters, 10(2000), pp. 2493-2495: This publication is cited in US8501730 as disclosing a process for preparing benzoic acid compounds (4) via Reaction Scheme C.

• Claim 1: This claim covers a process for producing a benzazepine compound of formula (1) by reacting a benzazepine compound of formula (2) with an amide compound of formula (3) in the presence of a carbonylating agent.

• Reasoning for Obviousness:

  • JP-A-4-154765 and Kondo (1999) both teach the synthesis of benzazepine compounds (1) and their utility as intermediates for vasopressin antagonists (10). While the '730 patent criticizes these methods for industrial scale, the general reaction types (coupling of a benzazepine core with a substituted benzoic acid derivative) were known.
  • A POSA, faced with the known utility of compounds (1) and the stated deficiencies of existing synthetic routes (low yield, purity, or inaccessible starting materials), would be motivated to find improved synthetic processes.
  • The '730 patent's Reaction Scheme I (Claim 1) describes a carbonylation reaction between compounds (2) and (3). Carbonylation reactions are well-established in organic synthesis for forming carbon-carbon bonds, particularly in the presence of transition metal catalysts like palladium compounds and phosphine ligands. The '730 patent specifically mentions palladium compounds (e.g., palladium acetate) and phosphoric compounds (e.g., triphenylphosphine) as catalysts.
  • Given the general knowledge of carbonylation reactions and the motivation to improve the synthesis of compound (1), a POSA would have a reasonable expectation of success in exploring such a route, even if the specific combination of reagents and conditions might require some optimization. The patent itself provides the detailed conditions for this process, which a POSA could implement or adapt.

Combination 2: JP-A-4-154765 and Yasuhiro Torisawa et al. (2000) rendering Claims 2-5 obvious.

• Prior Art:

  • JP-A-4-154765: As discussed above, this patent discloses the utility of benzoic acid compounds (4) as intermediates for pharmaceutically active vasopressin antagonists.
  • Yasuhiro Torisawa et al., Bioorganic & Medicinal Chemistry Letters, 10(2000), pp. 2493-2495: This publication explicitly teaches a process for preparing benzoic acid compounds (4) (Reaction Scheme C in US8501730).

• Claims 2-5: These claims describe various processes for producing benzoic acid compounds of formula (4) through reactions involving amide compounds (11), (12), (13), or (14), including reactions with oxalyl halides, oxidation, and hydrolysis.

• Reasoning for Obviousness:

  • The Torisawa (2000) paper directly discloses a method for preparing benzoic acid compounds (4). JP-A-4-154765 also highlights the utility of these compounds.
  • Claims 2-5 of US8501730 propose alternative or refined methods for synthesizing compound (4). A POSA, having access to the Torisawa (2000) method and understanding the importance of compound (4) (from JP-A-4-154765), would be motivated to explore different synthetic strategies to improve yield, purity, or efficiency, especially if the existing method had limitations for industrial scale (as implicitly suggested by the '730 patent's objective to provide an improved process for compound (4) on industrial scale).
  • The specific reactions recited in Claims 2-5 (reaction with oxalyl halide, oxidation, and hydrolysis) are all standard synthetic transformations known to a POSA for modifying functional groups and building molecular complexity. For example:
    • Reacting an amide (11) with an oxalyl halide (19) (Claim 2) is a known method for forming a diketone or related carbonyl structures.
    • Oxidation of an amide compound (12) or (14) (Claims 3 and 5) to form a carboxylic acid is a common synthetic strategy, depending on the nature of the "X3" or the specific structure of (14).
    • Hydrolysis of an amide compound (13) (Claim 4) to yield a carboxylic acid is a fundamental reaction in organic chemistry.
  • The selection of these known reactions to achieve a desired transformation on a known intermediate (4), especially with the explicit motivation to improve industrial applicability, would be considered obvious to a POSA.

Combination 3: JP-A-4-154765, Kazumi Kondo et al. (1999), and general knowledge of reduction chemistry rendering Claim 6 obvious.

• Prior Art:

  • JP-A-4-154765: Discloses the transformation of compound (1) into compound (10), where compound (10) is a pharmaceutically active vasopressin antagonist.
  • Kazumi Kondo et al., Bioorganic & Medicinal Chemistry 7 (1999), pp. 1743-1754: Also relevant for the synthesis of compound (1), which serves as the starting material for compound (10).

• Claim 6: This claim describes a process for producing a 2,3,4,5-tetrahydro-1H-1-benzazepine compound of formula (10) by reducing a benzazepine compound of formula (1) using a hydrogenating agent in an amount of 0.1 to 1 mole per 1 mole of compound (1).

• Reasoning for Obviousness:

  • The '730 patent states that compound (1) is converted to compound (10) by reduction with a hydrogenating agent. This general transformation is known from JP-A-4-154765.
  • The inventive step in Claim 6 lies in the specific amount of hydrogenating agent (0.1 to 1 mole per 1 mole of compound (1)), and the assertion that this specific range allows the reaction to proceed with "hardly occurring undesirable dehalogenating reaction."
  • However, a POSA would understand that controlling stoichiometry is a routine aspect of optimizing chemical reactions to favor desired products and minimize side reactions. Given that hydrogenating agents are well-known to perform reductions, and that excessive reducing agent can lead to over-reduction or side reactions like dehalogenation, a POSA would routinely experiment with varying amounts of reducing agent, including sub-stoichiometric or carefully controlled stoichiometric amounts, to achieve selectivity.
  • The patent itself lists common hydrogenating agents such as lithium aluminum hydride, sodium borohydride, zinc borohydride, and diborane. These are standard reagents in organic synthesis for the reduction of ketones (the transformation from compound (1) to (10) involves the reduction of a ketone to an alcohol).
  • Therefore, optimizing the amount of a known reducing agent to achieve selective reduction and minimize side reactions, even dehalogenation, would be considered routine experimentation and well within the skill of a POSA, especially with the known goal of producing compound (10) from compound (1). The identified range, while perhaps an optimal finding, is a result of routine experimentation rather than an inventive concept.

Conclusion on Obviousness

Based on the explicit admissions in the '730 patent regarding the existence and utility of prior art compounds and synthetic pathways (JP-A-4-154765, Kondo (1999), Torisawa (2000)), and the common knowledge of synthetic organic chemistry, a POSA would have been motivated to combine these teachings and apply routine experimentation to develop the processes claimed in US8501730. The claims represent improvements in yield and purity, and while valuable, these improvements stem from the optimization of known reactions and conditions rather than a fundamentally new chemical process, making them vulnerable to obviousness challenges. This is further supported by the Federal Circuit's affirmation of invalidity over the Kondo (1999) paper in the Otsuka Pharmaceutical Co. v. Lupin Ltd. case for the asserted method claims.