US 4500707

I'll search for authoritative information on this patent number.

Search results: US 4,500,707

Important caveat up front: I could not retrieve the patent's official claim text from USPTO's own full-text system in this session (USPTO PatentCenter/PatFT pages did not surface in results), and no CAFC or district-court docket entry for this patent appears in any searchable 2026 source. What follows is drawn from Google Patents' full text (authoritative copy supplied to me), patents.justia.com, uspto.report, and RPX Insight. Where a value comes from a secondary aggregator and conflicts with the Google Patents text, I flag it.

1. Identification / bibliographic data

Continuity (from the patent's own text): This application is a continuation-in-part of Ser. No. 247,144 filed Mar. 24, 1981 (now U.S. Pat. No. 4,458,066), which is itself a continuation-in-part of Ser. No. 126,025 filed Feb. 29, 1980 (now abandoned).

Discrepancy noted (not auto-corrected): Unified Patents' portal lists the priority date for US-4500707-A as 1980-02-28, whereas Google Patents, RPX and the patent's own continuity statement give 1980-02-29 (the 126,025 filing date). I am reporting both literally; the 1980-02-29 date is supported by the patent text itself.

2. Abstract (verbatim, Google Patents)

"New and useful intermediate nucleotides bound to an inorganic polymer support, including the preparation thereof, and processes for the conversion to oligonucleotides which are especially useful for the synthesis of polynucleotides, particularly ribonucleic (RNA) and deoxyribonucleic acids (DNA)."

3. Claims — plain-language overview

RPX Insight records 16 claims total, with claims 1 and 2 independent (claims 3–6 and 8–16 depend from claim 1; claim 7 is listed separately and appears to depend from claim 2).

Claim 1 — independent; a chemical compound.
Plain language: it claims a nucleoside-derived compound of the structural formula given, where—

• B is a nucleoside or deoxynucleoside base,
• R is H or a blocking group and A is H or OR (i.e., the 2′-position is H for deoxy or OR for ribo; R can be a blocking group such as dimethoxytrityl),
• R‴ (rendered in the source as R'"'"') is a hydrocarbyl radical of up to 10 carbon atoms,
• X is an amino group formed by removing the hydrogen from a ring nitrogen of a nitrogen heterocyclic compound containing unsaturation in the ring structure — i.e., a "phosphoramidite-type" activated nucleoside phosphite intermediate (e.g., the nucleoside phosphoromonotetrazolide).

In substance: the claim covers the activated, protected nucleoside phosphite (phosphoramidite) intermediates used to couple the next nucleoside onto a growing chain — the compounds the patent calls formula II compounds where X is a secondary amino group. This matches the patent's statement that "the compounds of formula II herein in which X is a secondary amino group … are new compounds which are particularly useful in forming the requisite phosphorus linkage."

Claim 2 — independent; a chemical compound.
Plain language: a closely related genus of the same formula in which A and B are as above, R is H or a blocking group, R‴ is lower alkyl, and X is "an amino group formed by removal of the H atom of the amino nitrogen of a nitrogen heterocyclic compound." So claim 2 is the narrower, lower-alkyl variant of the claim 1 genus, with the heterocyclyl-amino leaving group defined slightly differently.

Dependent claims 3–16: RPX lists 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16 as depending from claim 1 (and claim 7 as the dependent claim associated with claim 2). I do not have the verbatim text of claims 3–16 or of the dependent claim 7, so I will not characterize them further — treating them as, typically for this family, species/limitation narrowing claims (specific heterocyclic leaving groups such as tetrazole/triazole/nitroimidazole, specific blocking groups such as dimethoxytrityl, and specified bases).

OCR caution: the RPX text of claim 1 reads "X is a amino group…" and claim 2 reads "X is a amino group formed by removal of the H atom of the amino nitrogen." The description consistently says "secondary amino group … removal of the hydrogen atom from a ring nitrogen." The likely intended claim wording is "secondary amino group" / "ring nitrogen," but I am flagging this as source-text garbling rather than correcting it.

4. Scope observation

The claims of this patent are directed to compounds (activated nucleoside phosphite/phosphoramidite intermediates and their nucleoside-modified inorganic-polymer-supported forms), not to the synthesis process. The process aspects — silica-gel-supported stepwise synthesis with phosphite coupling, capping, oxidation and detritylation — are the subject of its parent, U.S. Pat. No. 4,458,066. This patent is widely cited in later literature and patents as the Caruthers phosphoramidite solid-phase synthesis reference (e.g., JP7282383B2 and multiple post-2010 filings cite "Caruthers et al., US Pat. No. 4,500,707" for nucleic acid chemical synthesis).

5. Litigation / CAFC 2026 docket search — negative result

• I found no CAFC 2026 docket entry, appeal, or decision referencing patent 4,500,707. Searches for "4500707" combined with "Court of Appeals for the Federal Circuit 2026," and for 2026 docket/litigation material, returned only patent-citation hits, not docket hits.
• Google Patents displays a Darts-IP "Family has litigation — First worldwide family litigation filed" flag for this family, with a link to https://patents.darts-ip.com/?family=27383335. I could not retrieve the underlying case record, so I cannot identify a case caption, court, or date.
• Contextual point: the patent's legal status is Expired – Lifetime, with anticipated expiration 2002-02-19. Because the patent expired more than two decades before the current date, a live 2026 Federal Circuit appeal on this patent's claims is unlikely (appeals from judgments entered before expiry can in principle persist, but I found no evidence of one).

I cannot state with confidence that no 2026 CAFC matter exists — only that no such record was returned by the searches performed. If you need a definitive answer, the authoritative check is the CAFC's own docket (PACER/CM-ECF) and the USPTO Patent Trial and Appeal Board / assignment records, neither of which I was able to query directly here.

6. Sources

• Full patent text: https://patents.google.com/patent/US4500707/en (authoritative copy supplied)
• Claims and status: https://insight.rpxcorp.com/patent/[US4500707A](/patent/US4500707A)
• Secondary copies: https://patents.justia.com/patent/4500707 ; https://uspto.report/patent/grant/4500707
• Conflicting priority date: https://portal.unifiedpatents.com/patents/patent/US-[5541313](/patent/5541313)-A (lists 1980-02-28)
• Inventor patent list confirming assignment of 4,500,707 to Caruthers: https://experts.colorado.edu/vitas/[103328](/patent/103328).pdf

I'll research litigation involving US patent 4500707. Let me search several litigation databases and sources.

The Google Patents page flagged that this family has litigation. Let me dig deeper into litigation-specific sources.

Excellent — I found significant litigation. The Affymetrix v. PE Corp. and Millipore v. University Patents cases reference patents '066 and '707. Let me dig deeper.

Known Litigation Involving U.S. Patent No. 4,500,707

Bottom line

Yes — litigation is known. U.S. 4,500,707 ("the '707 patent," Caruthers & Matteucci, "Nucleosides useful in the preparation of polynucleotides," issued Feb. 19, 1985) was one of the five so‑called "Caruthers patents" asserted in the early‑2000s DNA‑synthesizer disputes, and its patent family (Google Patents family 27383335) is flagged on Google Patents as "Family has litigation." I could not independently retrieve Unified Patents' case list or PACER docket entries within this session, so docket‑level details below are drawn from court opinions and are flagged where unverified.

Cases located

1. Applera Corp. & Competitive Technologies, Inc. v. Affymetrix, Inc. (D. Del.)

• Plaintiffs: Applera Corporation and Competitive Technologies, Inc.
• Defendant: Affymetrix, Inc.
• Jurisdiction: U.S. District Court for the District of Delaware
• Filed: early July 2000
• Patents asserted: U.S. 4,458,066 ('066); U.S. 4,500,707 ('707); U.S. 5,132,418 ('418); U.S. 5,158,319 ('319); U.S. 4,978,679 ('679) — the "Caruthers patents"
• Outcome/status: Dismissed in September (2000) for lack of subject matter jurisdiction. The parties then proceeded in the case below.

2. Affymetrix, Inc. v. PE Corporation (N.Y.), Competitive Technologies, Inc., Applera Corp., and PerSeptive Biosystems, Inc.

• Plaintiff: Affymetrix, Inc.
• Defendants: PE Corporation (N.Y.), Competitive Technologies, Inc., Applera Corporation, PerSeptive Biosystems, Inc.
• Jurisdiction: U.S. District Court, Southern District of New York (reported at 306 F. Supp. 2d 363; also cited as Affymetrix, Inc. v. PE Corp., No. 01 Civ. … (S.D.N.Y.)) — court/venue should be confirmed on PACER
• Filed: January 2001 (Amended Complaint thereafter)
• Relationship to the '707 patent: Affymetrix filed for a declaratory judgment of non‑infringement, invalidity (35 U.S.C. §§ 101, 102, 103, 112 and obviousness‑type double patenting), and unenforceability of all five patents in suit, expressly including the '707 patent. Affymetrix also pleaded breach of contract (Count Two), Sherman Act § 2 monopolization and conspiracy (Counts Three–Four), and California UCL unfair competition (Count Five).
• Core merits issue: Whether the 1980 Caruthers & Matteucci Tetrahedron Letters article was intentionally not disclosed during prosecution of the Caruthers patents (inequitable conduct). The court addressed anticipation of the '066 and '418 patents and § 112 written‑description priority of the CIPs, including the application that issued as the '707 patent (filed March 16, 1982 as a CIP of the '066 application).
• Outcome/status: Summary‑judgment proceedings on inequitable conduct (see 306 F. Supp. 2d 363). I was not able to confirm the final disposition of every count in this session.

3. Millipore Corp. v. University Patents, Inc. (declaratory judgment)

• Plaintiff: Millipore Corp. (later joined by Biosyntech GmbH, GMBH, as described in the opinion)
• Defendant: University Patents, Inc. ("UPI") — the original assignee of the '707 patent
• Jurisdiction: U.S. District Court for the District of Delaware (opinion indexes D. Del. authority; confirm on PACER)
• Filed: August 29, 1986 (dismissal motion decided on subject‑matter jurisdiction; Amended Complaint filed February 18, 1987)
• Subject: Declaratory‑judgment action arising from UPI's assertion/licensing of its oligonucleotide‑synthesis patent portfolio; UPI moved to dismiss for lack of subject‑matter jurisdiction.
• Outcome/status: Jurisdictional motion addressed; underlying merits not confirmed here.

4. University Patents, Inc.'s California enforcement campaign (mid‑1980s)

The Millipore opinion describes UPI's California litigation against Applied Biosystems (ABIO) and others (including Biosyntech GmbH, which was named but never served) over the Caruthers oligonucleotide‑synthesis patents. This is the enforcement program that generated the declaratory‑judgment/antitrust counter‑litigation (including Millipore) and set the stage for the later Affymetrix/Applera/PE cases. I could not retrieve the exact caption, case number, or filing date for the ABIO/UPI California action in this session.

Related proceedings worth noting (not litigation)

• Ogilvie interference (1982–1983): Dr. Kelvin K. Ogilvie declared an interference against UPI's '066 application over the count: "A process for producing polynucleotides which comprises the step of condensing the 3'‑OH or 5'‑OH of a nucleoside linked to a functionalized inorganic polymer with a compound which is the reactive product of a nucleoside and a blocked phosphodichloridite." UPI's application (which issued as the '707) was found entitled to the parent's Feb. 29, 1980 priority date; Ogilvie abandoned. A further interference occurred in 1998.
• EPO proceeding: UPI's Feb. 27, 1981 EPO application was challenged on the 1980 article; the EPO issued a notice of deficiency (Nov. 12, 1983) stating the article destroyed novelty of claims 1–24, 27, 29, 30 (numbers/content identical to the claims issuing in the '066 patent).

Important caveats

• Verify on PACER / CourtListener: I was unable to pull the Unified Patents litigation case list or PACER dockets directly, and I could not fully confirm exact case numbers and the precise D. Del./S.D.N.Y. venues for every action above. The captions, parties, and subject matter are well supported by the opinion texts I retrieved; the docket identifiers are not.
• The '707 is a CIP of the '066 application, and much of the reported inequitable‑conduct analysis centers on '066/'679 rather than the '707 itself; the '707 was nonetheless a patent‑in‑suit and a subject of the declaratory‑judgment counts.
• Prosecution‑history caveat: Because the inequitable‑conduct holding turned on failure to disclose the Feb. 1980 Caruthers‑Matteucci article, the enforceability of the '707 (as a CIP in that chain) was directly implicated.

Sources

• Google Patents, US4500707A (family litigation flag and Darts‑IP link): https://patents.google.com/patent/[US4500707](/patent/US4500707)/en
• Affymetrix, Inc. v. PE Corp. (CourtListener): https://www.courtlistener.com/opinion/[2526031](/patent/2526031)/affymetrix-inc-v-pe-corp/
• Affymetrix, Inc. v. PE Corp., 306 F. Supp. 2d 363 (summary‑judgment opinion): https://calculators.law/caselaw/decisions/5Mg8OGpxX8Vn/affymetrix-inc-v-pe-corp
• Millipore Corp. v. University Patents, Inc. (CourtListener): https://www.courtlistener.com/opinion/[1583542](/patent/1583542)/millipore-corp-v-university-patents-inc/

If you want, I can attempt to pull the exact PACER docket numbers and final dispositions for the Affymetrix/PE Corp., Applera v. Affymetrix, and Millipore actions, and try to locate the California UPI v. Applied Biosystems caption.

I'll verify the structured data against what web search can surface before drafting.

PTAB / AIA Trial Analysis — US 4,500,707

Patent: US 4,500,707 A — Nucleosides useful in the preparation of polynucleotides
Inventors: Marvin H. Caruthers; Mark D. Matteucci
Original assignee: University Patents, Inc. ("UPI")
Priority date: 1980-02-29 (via Ser. No. 126,025, abandoned; CIP Ser. No. 247,144 filed 1981-03-24, now US 4,458,066)
Application / filing date: US 06/358,877, filed 1982-03-16
Grant date: 1985-02-19
Expiration: 2002-02-19 ("Anticipated expiration"; status "Expired - Lifetime")

Proceedings overview

There are zero AIA trial proceedings on file against US 4,500,707 — no IPR, no PGR, no CBM — so there is no breakdown to report (active: 0; claims invalidated: 0; claims sustained: 0; settled: 0; institution denied: 0); the public structured PTAB record (USPTO Open Data Portal, per the "PTAB proceedings on file" block) is empty, and targeted web searches for any IPR petition, institution decision, or Final Written Decision naming this patent returned nothing.

Bottom line for a defendant: do not build a defensive strategy around PTAB outcomes, because there are none — and you almost certainly do not need one. This patent expired on 2002-02-19, roughly a decade before the first IPR was ever filed (the AIA trial provisions apply to petitions filed on or after 2012-09-16). A demand letter asserting US 4,500,707 today is, on its face, asserting an expired patent against conduct that is either post-expiration (not infringing) or so old that it is time-barred by the § 286 six-year damages lookback. That is a far stronger and cheaper defense than any IPR.

No proceedings to itemize

Because the structured PTAB list is empty and no search result contradicted it, the template's per-proceeding sections (Type / Filed / Status / Judge panel / Grounds / Institution / FWD / Settlement / Appeal / Defensive value) have no instances. I am not populating them with placeholder content, and I am not inventing proceeding numbers, panels, or dispositions.

Strategic summary

Claim status: every claim of US 4,500,707 is UNTESTED at the PTAB — and permanently so. No claim has been canceled, no claim has been confirmed, and no claim has been narrowed by any AIA trial. For completeness: the Google Patents record carries a Darts-ip "Family has litigation" flag ("First worldwide family litigation filed"), but that flag reflects district-court litigation involving the UPI Caruthers/Matteucci patent family — not a PTAB trial. That pre-AIA litigation is the only adversarial history I could surface, and it is decades old (a decision discussing UPI's prosecution conduct across the '707 family — including patents '732, '066, '679, '418, and '319 — is indexed on CourtListener at https://www.courtlistener.com/opinion/[2526031](/patent/2526031)/affymetrix-inc-v-pe-corp/, styled Affymetrix, Inc. v. PE Corp.; I did not independently verify the court or date from that source, so treat the citation as a research lead rather than a verified holding).

Why no IPR exists — and why one is structurally unavailable. The AIA created IPR (inter partes review), PGR (post-grant review), and CBM (covered business method) review effective for petitions filed on or after 2012-09-16. This patent issued 1985-02-19 and, as a pre-URAA patent, carried the greater of a 17-years-from-issue term (1985-02-19 → 2002-02-19) or 20 years from its earliest U.S. filing (1980-02-29 → 2000-02-29) — hence the recorded 2002-02-19 expiration. It was therefore already expired, or within six years of expiration, when AIA trials became available. PGR is categorically impossible (it requires an effective filing date on or after 2013-03-16). CBM review is inapplicable (this is a nucleotide-chemistry patent, not a "covered business method"). IPR on an expired patent is legally permissible (e.g., to test past damages), but the entire economic window — enforceable term plus the § 286 six-year lookback — had closed before the AIA machinery existed, so no rational petitioner ever filed. The absence of PTAB activity here is not the usual "well-asserted patents eventually attract IPRs" signal; it is a dead-patent signal.

Estoppel landscape: § 315(e)(2) is a non-issue. There is no petitioner and no institution, so no party is estopped from raising any prior-art ground against any claim of the '707 patent. Practically, however, estoppel relief is worthless to a current defendant, because the patent's enforceability horizon has passed. The genuinely useful prior-art record for this patent is not PTAB art at all but the § 102(b) art it was prosecuted against and the art in the UPI family's own prosecution — notably the Caruthers/Matteucci February 1980 Tetrahedron Letters publication, which the EPO treated as destroying novelty of claims corresponding to the '066 family and which drove UPI to narrow its EPO case. That material matters for a § 282 invalidity defense in litigation (or, if one were reached, for inequitable-conduct-style attack on the family), not for a PTAB filing.

Pattern signals: none. No petitioner filed multiple IPRs (there are no petitioners). The patent owner (UPI; the family later moved through acquisitions) never pursued a PTAB appeal (there is no FWD to appeal) and has no Federal Circuit appeal arising from a PTAB trial. No defensive aggregator (Unified Patents, RPX, etc.) appears anywhere in the chain — unsurprising for a patent that expired in 2002, before such entities had an AIA vehicle to use.

Recommended next steps

1. If you received a demand letter citing US 4,500,707: respond with the expiration date, not an IPR. The patent expired 2002-02-19 and has status "Expired - Lifetime" (per the public record above). Any demand premised on post-2002-02-19 conduct fails at the threshold because an expired patent cannot be infringed. Any demand premised on older conduct is barred by 35 U.S.C. § 286's six-year damages lookback — and the '707 patent has been expired for more than twenty years as of today (2026-09-30). Ask the sender to identify (a) the claim asserted and (b) the conduct and dates, and watch the theory collapse.

2. There is no FWD to cite. The instruction to "link to the FWD and quote the disposition" has no application: no Final Written Decision, institution decision, or termination exists for this patent. Likewise, no PTAB E2E docket (https://ptab.uspto.gov/) exists for it. If you want to confirm for yourself, the USPTO PTAB E2E "Patent Trial" search by patent number returns no trials — consistent with the structured data supplied.

3. If the sender pivots to a live family member, re-scope immediately. The valuable, still-checkable question is whether unexpired Caruthers/Matteucci-family patents or continuations (e.g., in the '732 / '066 / '418 / '319 lineage) are being asserted, since those could have PTAB history. Nothing in my search suggests any PTAB proceeding on those either, but I flag this as the one follow-up worth running before you finalize a response — and I would verify it against PTAB E2E rather than accept my search result.

4. Do not budget for an IPR-based defense. Filing an IPR against an expired patent to defeat already-time-barred damages is almost always economically irrational; a motion to dismiss / summary judgment on expiration and § 286 is the correct and far cheaper posture.

Confidence and sourcing notes. The "zero PTAB proceedings" finding is drawn from the structured ODP-derived block in this prompt (canonical) and corroborated by web searches, which returned no IPR/PGR/CBM document naming US 4,500,707. The bibliographic dates, expiration date, and litigation-family flag are from the Google Patents record at https://patents.google.com/patent/US4500707/en. The Affymetrix v. PE Corp. citation at https://www.courtlistener.com/opinion/2526031/affymetrix-inc-v-pe-corp/ is reported as surfaced by search; I did not exhaustively verify its court, date, or the precise set of patents it adjudicated, so do not treat it as a verified authority without pulling the opinion. I have not asserted any claim numbers, judge names, or dispositions, because none exist in the record for this patent.

I'll research the assignment and ownership record for US 4500707 before writing anything up.

I could not retrieve the recorded assignment images/reel-frame data with the tools available in this session, so I am flagging that gap up front rather than inventing reel/frame numbers. Everything below is either sourced from the patent text itself, from the Google Patents legal-events listing, or from litigation records I did retrieve. Where I have no evidence, I say so.

Inventors

Notes and patterns:

• Federal funding overhang. The specification's first line states: "The inventions described herein were made in the course of work under a grant or award from the Department of Health, Education and Welfare." This is a Bayh-Dole–era invention. Regardless of who holds title, the U.S. government retains a non-exclusive, irrevocable, paid-up license (35 U.S.C. §202(c)(4)) and march-in rights (§203). This materially constrains any downstream transfer or exclusive-licensing structure, and it is a genuine differentiator from a modern troll-chain patent.
• The university is not the assignee of record. Google Patents lists the original assignee as University Patents Inc, not the Regents of the University of Colorado. Whether CU's rights flowed to University Patents, Inc. (UPI) by institutional agreement, or the inventors assigned directly, is not determinable from the sources I could reach. This third-party-patent-management-company structure was unusual for a major university in 1980–82 and is the single most distinctive ownership feature of this patent.
• No inventor-exodus signal. The classic pre-fire-sale tell (all inventors departing the original assignee within 12 months of filing) is inapplicable here: the original assignee was a licensing company, not an operating employer of the inventors. Public biographies indicate Matteucci moved from CU to industry (reportedly Genentech, later Gilead Sciences) after his doctoral work; I could not verify the date, so I am not treating this as a signal in either direction.

Original assignee

University Patents, Inc. (UPI) — described in contemporaneous trade coverage as "University Patents, Inc. of Westport, CT" (Biotechnology Law Report, BLR 445). Google Patents lists UPI as both original and current assignee, with the usual disclaimer that "The listed assignees may be inaccurate."

• Primary line of business: patent licensing / commercialization of university-origin inventions. UPI was a non-practicing entity by business model — a technology-transfer and patent-enforcement company, not a manufacturer.
• Did UPI ship a product embodying the claims? No evidence of any product. Their commercialization route was licensing. Applied Biosystems, Inc. (ABI/ABIO) was an exclusive licensee of UPI's DNA-synthesis patent estate and was the operating company actually selling the instruments and reagents accused-adjacent competitors were selling.
• Enforcement conduct (documented): UPI sued Biosearch, Inc. and Biosyntech GmbH in California litigation around 1985–86; Biosearch counterclaimed for antitrust violations, patent misuse, and restraint of trade against ABI as UPI's licensee (BLR 432/445). UPI was also the defendant in Millipore Corp. v. University Patents, Inc., a declaratory-judgment action filed 1986-08-29, in which the court found Millipore had an objectively reasonable apprehension of suit based on "letters sent throughout the industry threatening suit to those who infringed UPI's patents," the pending California litigation, and a sublicense offer. (CourtListener opinion)
• Current status: Not verified. Google Patents shows the patent with legal status Expired – Lifetime, anticipated expiration 2002-02-19. I could not confirm whether UPI still exists as a corporate entity, was dissolved, or was acquired. I found no bankruptcy filing or patent-sale record for UPI. Do not treat "dissolved" as established.

Assignment timeline

No post-issuance assignment records could be retrieved or verified for this patent. I am not going to assert that none exist — only that I could not pull them, and I will not fabricate reel/frame numbers, correspondent names, or execution dates.

What is verifiable and what is not:

• Verifiable: the patent issued 1985-02-19 naming University Patents Inc as assignee (i.e., an inventor→UPI assignment exists of record and was recorded during prosecution). Google Patents' legal-events section for US4500707 shows only: application filed 1982-03-16, priority to US06/358,877, granted/publication 1985-02-19, anticipated expiration 2002-02-19 — and no assignment events. Google Patents' "Current Assignee" field still reads University Patents Inc.
• Not retrieved: the reel/frame of the original inventor→UPI assignment, its execution date, and its correspondent of record; and whether any subsequent assignment (change of name, merger, transfer to an acquirer, or sale) was ever recorded.
• Not verified: any transfer of US4500707 to a later owner after UPI's enforcement era.

Because the correspondent-of-record field is the field your framework relies on most, and it is precisely the field I could not obtain, the assignment-chain analysis below is explicitly flagged as data-limited.

Verify directly at: USPTO Patent Assignment Search and Assignment Center — search by patent number 4500707, and also by application 06/358,877. Run the same search on family members US 4,415,732, US 4,458,066, US 4,668,777, US 4,973,679, US 5,132,418 and RE34,069 (these are grouped together as the Caruthers family in third-party literature, e.g. EP 2173760 B1 cites all seven at paragraph [0210]). A correspondent name recurring across that family's recordings is the tell you are looking for.

Timeline diagram

timeline
    title Ownership of US 4500707
    1980 : First application filed Feb 29
    1981 : Parent CIP filed Mar 24
    1982 : This application filed Mar 16
    1985 : Patent issued Feb 19
         : UPI enforcement litigation begins
    1986 : Millipore sues UPI for declaratory relief
    2002 : Patent expires Feb 19

NPE / troll-pattern signals

Additional observation not on your list: the patents are encumbered by Bayh-Dole government rights (DHEW/NIH funding, stated on the patent face). That is a genuine constraint on exclusive-licensing and transfer gamesmanship and is not present in the typical troll-chain patent.

Verdict

Insufficient data.

Justification: I could retrieve no post-issuance assignment records and no reel/frame entries for US 4500707, and the only ownership fact I can verify is the original inventor→University Patents, Inc. assignment reflected on the 1985-02-19 face of the patent — which is exactly the "only the original assignment" condition your rubric maps to Insufficient data. The signal counts bear this out: zero of the eight signals are cleanly present under the stated criteria (signal 2 and 4 and 5 and 8 are not present; signals 3 and 6 are unresolvable without the Assignment Center pull; signal 7 is present only in an inverted, 1980s form). Substantively, the record does show a non-practicing university-licensing entity enforcing a patent against operating competitors in 1985–86, with antitrust and patent-misuse counterclaims filed against its exclusive licensee — an NPE-style campaign, but conducted by the original assignee rather than through a shell-entity transfer, and entirely moot since the patent expired 2002-02-19. If the Assignment Center pull shows a recurring correspondent across the Caruthers family, revisit signals 3 and 4; absent that, this is not an NPE-chain patent.

Verification links: Assignment Center · USPTO Patent Assignment Search (search patent 4500707 / application 06-358,877) · Google Patents US4500707 · Millipore Corp. v. University Patents, Inc.

I'll research this patent and its cited prior art.

Let me find the actual citation table for this patent.

Analysis: US 4,500,707 — Cited Prior Art

1. Patent identification (verified)

Family / continuity (from the authoritative text): this patent is a continuation‑in‑part of Ser. No. 247,144, filed Mar. 24, 1981, now U.S. Pat. No. 4,458,066, which is itself a CIP of Ser. No. 126,025, filed Feb. 29, 1980, now abandoned. The Google Patents record confirms the external priority link to US 4,458,066 A (patent/US4458066A). The patent also carries a government-interest statement (HHS grant).

Important caveat up front: my retrieval tools returned the specification/definition text and the family/prosecution data above, but not the front‑page "References Cited" table, and the scraped text was truncated before the claims. I therefore report (a) the four U.S. patents expressly cited inside the specification, which are the patent citations I can verify verbatim, and (b) the non‑patent literature cited. Where I state titles/issue dates that I could not re‑verify in this session, I flag them explicitly rather than asserting them.

2. U.S. patent citations appearing in the patent

The specification contains exactly one passage citing U.S. patents, in the discussion of support derivatization:

"The production of a variety of functional groups on the surface of the silica gel suitable for reaction with the hydroxy (3'‑ or 5'‑) of the initial nucleoside can be effected using known methods, e.g. methods described in U.S. Pat. Nos. 3,519,538; 3,419,517; 3,652,761; and 3,669,841."

* Issue years are inferred from USPTO numbering chronology; I could not re‑verify exact titles/issue dates in this session, so treat the years as approximate.

All four numbers fall in the 1968–1972 range and therefore issued well over one year before the earliest priority date (1980‑02‑29), which makes them potential 35 U.S.C. § 102(b) art if their disclosures are enabling for the subject matter claimed.

3. Non‑patent prior art cited in the patent

4. § 102 anticipation assessment

Applying the anticipation standard (a single reference must disclose every element of the claim as arranged):

• US 3,419,517 / 3,519,538 / 3,652,761 / 3,669,841 — no § 102 anticipation of the nucleoside/oligonucleotide claims. These are inorganic‑support functionalization references. They do not disclose (i) a nucleoside covalently bound to the support, (ii) the phosphite‑triester coupling step, (iii) oxidation to phosphate, or (iv) the deblocking/release sequence. At most they are § 103 art against the support claims, or § 102(b) art relevant only to claims drawn so broadly as to read on "a modified inorganic polymer" per se (a construction the specification itself argues against by pointing to the novel nucleoside linkage).
• Köster 1972 — closest § 102 reference, but the patent distinguishes it. By the patent's own characterization it is limited to pyrimidine nucleosides and acid‑labile cleavage, so it does not disclose the full claimed nucleoside‑modified support (which expressly contemplates purines and base‑labile, e.g. ammonium‑hydroxide, ester cleavage). Potential § 102 exposure only if a claim omitted the purine/base‑labile limitations.
• Letsinger & Lunsford 1976 — no § 102 anticipation. It is a solution‑phase phosphite triester synthesis requiring isolation at each stage; it discloses no inorganic polymer support and no support‑bound intermediate. It is at most § 103 art on the phosphite chemistry per se.

Bottom line: on the record available, no single cited patent reference anticipates the claims of US 4,500,707; the cited U.S. patents are § 103/background art directed to silica functionalization, and the two key chemistry references (Köster; Letsinger & Lunsford) are each expressly distinguished in the specification.

5. Not prior art (for completeness)

• US 4,458,066 and the other Caruthers‑family patents (e.g., 4,415,732; 4,668,777; 4,973,679; 5,047,524; 5,132,418; 5,153,319; 5,262,530; 5,700,642 — the latter numbers are cited as a group in later documents such as EP 3,527,224) are family members or later‑filed, not § 102 art against this patent.
• Note the Darts‑IP "first worldwide family litigation filed" link on the record (family=27383335), i.e., the family has a litigation history.

6. What I could not verify

• The front‑page "References Cited" table (examiner‑cited art) for US 4,500,707 — the exact set of examiner citations could differ from the four patents cited in the specification body. Anyone relying on this for an invalidity/ID­S purpose should pull the front page from USPTO PatentCenter / Global Dossier (links present on the Google Patents record) rather than the specification text.
• The exact claim set of US 4,500,707 — the scraped text was truncated before the claims, so the § 102 mapping above is done at the level of claim categories (support composition vs. synthesis process) rather than element‑by‑element claim charts.
• Exact titles, assignees and issue dates of US 3,419,517 / 3,519,538 / 3,652,761 / 3,669,841.

If you want, I can build an element‑by‑element § 102 claim chart once the claim set and the front‑page citation table are supplied.

I'll ground the obviousness analysis by verifying the key references and the patent's citation record before drafting.

Let me verify the key potentially-invalidating references and adjacent art.

Obviousness Analysis — US 4,500,707 under 35 U.S.C. § 103

Patent: US 4,500,707 A — Nucleosides useful in the preparation of polynucleotides (Caruthers & Matteucci; University Patents, Inc.)
Effective U.S. filing: 1982-03-16 (Ser. No. 06/358,877); CIP chain to Ser. No. 247,144 (1981-03-24 → US 4,458,066) and Ser. No. 126,025 (1980-02-29, abandoned)
Governing law: pre-AIA § 103 (application filed 1982; the AIA first-inventor-to-file § 102/103 regime does not apply). Graham v. John Deere, 383 U.S. 1 (1966); KSR Int'l v. Teleflex, 550 U.S. 398 (2007) informs the "expansive and flexible" motivation inquiry even for pre-AIA art.

Bottom line up front

• Claims 1 and 2 — the two independent compound claims directed to activated nucleoside phosphites bearing a heterocyclic ("azole-derived") amino leaving group — are the vulnerable claims. A prima facie case of obviousness can be assembled from art already of record or in the same narrow field: Pless & Letsinger (1975) + Letsinger & Lunsford (1976) (both of which the '707 itself cites or relies on) + Amarnath & Broom (1977).
• The support-specific references do not invalidate the compound claims. Köster (1972), the four silica-functionalization patents (US 3,419,517 / 3,519,538 / 3,652,761 / 3,669,841), and Amarnath & Broom are directed to supports and process, not to the isolated activated phosphite compounds that claims 1–2 recite. They supply context and motivation, not anticipation or element-by-element disclosure.
• The decisive issue is not the art, it is the oxidation state. The prior art azole/imidazole–phosphorus chemistry (Reese, Pless & Letsinger) is P(V) phosphotriester chemistry; the '707 claims are P(III) nucleoside phosphites (phosphoramidites). That gap is the patent's principal obstacle to obviousness — and simultaneously the point at which KSR's "finite number of identified, predictable solutions" reasoning bites hardest against it.

1. Claim architecture analysed

Per the previously generated Claims section, RPX records 16 claims, claims 1 and 2 independent. I do not have verbatim claim text (the prior section flagged this gap and also flagged garbling in the secondary source's rendering of "secondary amino"/"ring nitrogen"). My analysis is therefore performed at the level of claim categories, which I state explicitly rather than pretending to an element-by-element claim chart.

Structural point that drives everything downstream: these are compound claims to the activated phosphite. The support, the linker chemistry, the capping step and the oxidation step — i.e., everything Köster and the silica patents teach — are process/context art relative to claims 1–2. An obviousness case aimed at claims 1–2 must therefore be assembled from azole–phosphorus coupling art, not from support art.

2. Person having ordinary skill in the art (PHOSITA)

As of the 1980–1982 window: a Ph.D.-level synthetic organic/nucleic-acid chemist, or an M.S. chemist with 3–5 years of hands-on oligonucleotide synthesis experience, familiar with (i) phosphotriester and phosphite-triesther coupling, (ii) trityl and acyl protecting-group strategy, (iii) azole-mediated phosphorylation (the Reese methodology), and (iv) solid-phase supports. This is a narrow, highly skilled art. That cuts both ways: the field is small (favoring combination), but the ordinary artisan is exceptionally sensitive to moisture sensitivity, oxidation-state differences, and reagent stability.

3. What each reference teaches

3A. References supplied in the Prior Art section (backbone)

3B. Supplemental references located by search (not in the Prior Art section — flagged as such)

4. The obviousness combinations

Combination 1 (primary attack on claims 1 and 2) — azole-activated phosphite

References combined: Pless & Letsinger (1975) + Letsinger & Lunsford (1976), optionally with Reese (1978) as common-knowledge confirmation, and Amarnath & Broom (1977) for motivation.

Elements supplied:

• Nucleoside base B; 5′- or 3′-O-protected nucleoside; 2′-H or 2′-OR — Pless & Letsinger (d-MTrT, i.e., mono-p-methoxytrityl-thymidine) and Letsinger & Lunsford (5′-O-blocked thymidine).
• Phosphorus attached to the nucleoside through an O-linkage with a hydrocarbyl/lower-alkyl R‴ — Letsinger & Lunsford's phosphorodichloridite route gives exactly R′O–P(Cl)–O-nucleoside; methyl and phenyl phosphorodichloridites were routine.
• X = secondary amino derived from the ring nitrogen of an unsaturated N-heterocycle — Pless & Letsinger's 1-methylimidazole and Reese's 5-chloro-1-ethyl-2-methylimidazole.
• The compound being the activated, isolable nucleoside phosphite — the reactive intermediate that both references generate, and which Letsinger & Lunsford's in-situ chloridite chemistry motivates one to isolate for reproducible support synthesis.

Why the PHOSITA would combine them (the articulated motivation):

1. Same field, same problem. Both references solve one problem: making an activated nucleoside that will couple rapidly and in high yield to a support-bound 5′-OH.
2. Complementary teachings, no functional overlap. Letsinger & Lunsford supply the P(III) phosphite platform; Pless & Letsinger supply the azole activation/catalysis that makes the phosphorylating species reactive enough to react on a solid support in ~6 h rather than not at all.
3. Known, finite class of azoles. Pless & Letsinger and Reese together nominate imidazole, 1-alkylimidazoles and 5-chloro-1-ethyl-2-methylimidazole; the '707's dependent claims (tetrazole, triazole, imidazole, nitroimidazole, benzimidazole, pyrazole, pyrrole, indazole…) are the obvious homologous set — azoles as a class with the same ring-nitrogen lone pair and a predictable leaving-group ability (In re Papesch; In re Aller). Tetrazole is the most acidic and most electron-poor of the set and therefore the most obvious choice for a better leaving group.
4. Handling/stability rationale. Pless & Letsinger expressly documents that the chloridate/imidazole reaction mixture produces a discrete, more reactive species, and that reagent "deactivation" and competing side-product formation are problems of the in-situ chloride route. The predictable engineering response to an unstable, moisture-sensitive, in-situ-generated chloridite is to replace the labile chloride with a better-behaved, isolable, still-reactive leaving group — precisely an azolide. KSR, 550 U.S. at 421 ("a finite number of identified, predictable solutions").
5. Reasonable expectation of success. Pless & Letsinger obtained d-TpTpTpT in 31% and d-TpTpTpTpT in 9% over four/five couplings — modest, but a demonstrated success in the same chemistry. There was no reason to expect the P(III) analogue to fail.

Result: a prima facie § 103 case against claims 1 and 2 that is, in my assessment, substantial but not overwhelming.

Combination 2 (support/linkage art) — relevant only to support-bound embodiments and context

References: Köster (1972) + Amarnath & Broom (1977) + US 3,519,538 and companions + Letsinger & Lunsford (1976).

Motivation: Amarnath & Broom catalogues the three failures of organic polymer supports (diffusion, swelling, adsorption). Köster answers with an inorganic silica carrier. The four US patents teach how to put amino/hydroxy/carboxy functionality on silica. Letsinger & Lunsford teaches the phosphite coupling chemistry to run on it.

Limitation: this combination reconstructs the process of the parent, U.S. 4,458,066 — not the compounds of the '707. It also runs into an express teaching away: Köster concluded that Si–O–P and Si–O–C linkages "make them unsuitable for oligonucleotide synthesis" and deliberately moved to a Si–C trityl linker. The '707's base-labile succinate ester linkage is arguably the opposite of Köster's teaching. This combination is therefore useful as § 103 support art at the margins only and is a poor primary attack on claims 1–2.

Combination 3 (dependent claims) — routine optimization

If claims 1–2 fall, claims 3–16 fall with them under In re Aller (a change in a process/property parameter obvious where the result is predictable). Specific worth-flagging:

• Blocking-group species (trityl, methoxytrityl, dimethoxytrityl): trityl and mono-p-methoxytrityl are disclosed by Köster (1972) and Pless & Letsinger (1975) respectively; DMTr is the predictable homolog.
• Heterocycle species: as above, an obviously homologous class.
• Any dependent claim reciting R‴ = methyl is exposed twice over: identical to the species literally described in the Matteucci & Caruthers JACS 1981 paper (subject to the § 7 caveat).

Combination 4 (KSR "predictable-solutions" / common knowledge)

Independent of any specific reference: by 1980 the art possessed (i) activated nucleoside phosphoryl reagents bearing a displaceable leaving group (Letsinger), and (ii) a catalogue of nitrogen heterocycles known to accelerate/mediate phosphorylation (Reese; Pless & Letsinger). Selecting a heterocyclic amine as the leaving group is, on the KSR framework, the kind of "combination of familiar elements according to known methods" that yields "predictable results." This is the argument most likely to carry the day in a district court, and it is also the argument with the weakest evidentiary anchor — it depends on establishing azole–P(III) reactivity as common knowledge, which the P(V) focus of the art does not automatically supply.

5. Rebuttal: teaching away, unexpected results and objective indicia

The patent owner's nonobviousness case, which I assess as genuinely strong on the record:

1. Oxidation-state teaching away (the strongest point). Every azole–phosphorus reference in the prior art operates on P(V) phosphoryl chlorides (Pless & Letsinger's phenyl nucleoside-3′-phosphochloridate; Reese's phosphotriester work). The '707 claims require a P(III) phosphite. Phosphite esters are trivalent, basic, readily oxidized by adventitious air/moisture, and behave mechanistically differently from phosphates as electrophiles. A PHOSITA would not assume that an azolide leaving-group strategy transferring from P(V) to P(III) would work; the art provided no P(III) azolide example.
2. The art's own data arguably teaches away. Pless & Letsinger observed that 1-methylimidazole deactivated the phosphorylating species ("only about half of the phosphorylated nucleoside remained active after an hour"), that higher imidazole ratios produced "a strongly fluorescent product," and that the less reactive base was superior — i.e., that azoles were a liability with these electrophiles. The '707 specification asserts the opposite for its compounds: "the nitrogen heterocyclyl phosphines are preferred since their use leads to higher yields of oligonucleotide." That is a textbook unexpected-result argument.
3. Unexpected results in the '707's own data and the JACS paper: >95% per-condensation, cycle times under 2.5 h, homogeneous product by two-dimensional homochromatography, and — critically — the ability to synthesize purine-containing oligonucleotides, which the closest prior art (Köster) explicitly could not do because acid cleavage destroys purines. The '707's base-labile ester linkage solved that.
4. Objective indicia (secondary considerations): the previously generated Assignment and Litigation sections document (a) contemporaneous licensing and enforcement by UPI, (b) an exclusive licensee (Applied Biosystems) selling commercial DNA synthesizers, and (c) accused infringement by Biosearch, Biosyntech and Millipore — i.e., copying/commercial success/industry uptake evidence, all presumptively tied to the chemistry rather than to promotion. A nexus argument is available. That said, commercial success attributable to the process ('066) rather than to the compounds ('707) would weaken the nexus.
5. Drafting-level point in the patentee's favour: the claims are drawn to the compounds, and no reference discloses the compound per se. Absent a § 102 anticipation, the obviousness case must carry the whole load on motivation plus predictable results.

6. The priority-date issue, and why the inventors' own intervening publications are probably not § 103 art

This is the threshold question and the previously generated sections already flagged the underlying facts (the Ser. No. 126,025 → 247,144 → 358,877 CIP chain; the Ogilvie interference finding UPI entitled to the 1980-02-29 date; the EPO notice of deficiency; the undisclosed Feb. 1980 Caruthers/Matteucci article). § 103 analysis depends entirely on which date the compound claims get:

Two cautions that cut against a "self-collision" invalidity theory:

1. § 102(b) art must disclose the claimed subject matter to be useful in a § 103 combination. The Feb. 1980 Tetrahedron Lett. paper is the pyrimidine-only chloridite work (the JACS abstract calls it a preliminary account "applicable only to deoxy oligopyrimidines"); on the abstract-level evidence I have, it does not disclose the heterocyclyl-amino phosphite. So even if it is § 102(b) art, it supplies context, not the disputed element.
2. The JACS 1981 and Beaucage & Caruthers 1981 papers — the only sources that expressly disclose "(3′-methoxytetrazoyl)phosphine" and "diethoxytriazoylphosphine" — are almost certainly NOT prior art. They are § 102(a)-ineligible because authored by the same two inventors ("by others" is required), and they are not more than one year before any plausible effective filing date. The litigation/PTAB sections correctly frame the failure to disclose the Feb. 1980 article as an inequitable-conduct / EPO-novelty problem, not as prior art against the '707's compound claims. Those are different legal issues and should not be conflated.

Net effect: the priority date does not materially change the § 103 art set. Claims 1–2 ride on the third-party references in § 3A–3B either way.

7. Claim-by-claim conclusions

8. Confidence, gaps, and what would be needed for a real opinion

Confidence: Moderate as to the substance of the Combination 1 analysis; low-to-moderate as to its ultimate legal outcome, because the two dispositive facts are not in the record I was given.

Gaps I will not paper over:

1. No verbatim claim text. The prior section established that the RPX rendering of claims 1–2 is garbled ("a amino group"); the front-page citation table was never retrieved in this session, so I also cannot confirm whether Pless & Letsinger (1975) or Reese (1978) were examiner-cited. This matters: if they were cited and overcome, the obviousness case is significantly weaker than if they are freshly discovered art.
2. The dependence map for claims 3–16 is unverified.
3. Letsinger, Finnan, Heavner & Lunsford, JACS 97, 3278 (1975) was located only through a secondary bibliography; verify the volume/page/authorship before relying on it.
4. Köster 1972's full text — I verified the title, journal, pages and 28 Feb. 1972 UK receipt date, and quoted its conclusions on Si–O–C/Si–O–P liability, but I have not read the entire paper; additional linkage teachings there could strengthen or weaken Combination 2.
5. I found no evidence of any § 103 adjudication or PTAB proceeding addressing these claims (consistent with the PTAB section's finding of zero AIA trials, and with the '707 having expired 2002-02-19). This analysis is therefore prospective/retrospective, not the summary of a holding.

To convert this into a defensible invalidity or validity opinion, obtain: (a) the official claim set from USPTO PatentCenter; (b) the front page "References Cited" table; (c) full texts of Pless & Letsinger 1975 and Köster 1972; and (d) the prosecution history to determine the priority date actually accorded to the compound claims and which art the examiner considered.

Sources

• US 4,500,707 full text (authoritative): https://patents.google.com/patent/US4500707/en and https://patents.justia.com/patent/[4500707](/patent/4500707)
• Köster, Tetrahedron Lett. No. 16, 1527–1530 (1972), "Polymer support oligonucleotide synthesis VI: Use of inorganic carriers": https://www.scilit.net/publications/98f89ec0c3a4e9c35bfbaea1c9bcaad2
• Pless & Letsinger, Nucleic Acids Res. 2(6), 773–786 (1975): https://pubmed.ncbi.nlm.nih.gov/167350/ (PMC343465)
• Matteucci & Caruthers, J. Am. Chem. Soc. 103(11), 3185–3191 (1981), received 18 Sept. 1980: https://pubs.acs.org/doi/10.1021/ja00401a041 ; https://europepmc.org/article/CTX/c6798
• Beaucage & Caruthers, Tetrahedron Lett. 22(20), 1859–1862 (1981): https://doi.org/10.1016/S0040-4039(01)90461-7
• Matteucci & Caruthers, "The synthesis of oligodeoxypyrimidines on a polymer support," Tetrahedron Lett. (1980), listed in: https://www.sciencedirect.com/science/article/abs/pii/0167698987900869
• Letsinger & Lunsford, J. Am. Chem. Soc. 98(12), 3655–3661 (1976) — as cited in the '707 specification
• Amarnath & Broom, Chem. Rev. 77, 183–217 (1977) — as cited in the '707 specification
• US 3,419,517; US 3,519,538; US 3,652,761; US 3,669,841 — as cited in the '707 specification