US 4978679

I'll search for litigation and docket information on this patent, then summarize.

Let me run a couple more targeted searches to confirm litigation/docket status.

Search Result on Litigation/Dockets

No litigation or appellate records were found for U.S. Patent No. 4,978,679.

• Searches across general web/patent-document sources returned no district court complaints, no PTAB/IPR proceedings, and no CAFC dockets (2026 or otherwise) naming this patent. The patent is unrelated to the Amgen/Regeneron/Alexion/AstraZeneca litigations that dominated results for other patent numbers.
• The only "hits" were an unrelated Texas voter-registration PDF containing the coincidental number "4978679," and citation listings of US4978679A as a prior-art reference in later patents (e.g., EP3791880A1 / RU2746945C2 and US20150272917, which list it among 5‑lipoxygenase inhibitors incorporated by reference).
• Caveat (explicit uncertainty): I was not able to query USPTO Patent Center or the CAFC docket system directly with the tools available; my conclusion rests on web search results. Absence of a hit is not affirmative proof that no proceeding ever existed. Given the patent lapsed in 1995 for non‑payment of maintenance fees (see below), litigation is highly unlikely.

US 4,978,679 — Summary

Abstract

Positions 7- and/or 6-substituted 1,2,3,4,4a,9b-hexahydro-8-hydroxydibenzofuran-3-ols and analogs of that general structure are described. These compounds are potent inhibitors of 5‑lipoxygenase, an enzyme crucial to leukotriene biosynthesis, and are useful in treating a variety of inflammatory conditions.

Technology overview

The compounds are tricyclic hexahydrodibenzofuran-3-ols bearing a hydroxyl at the 8‑position and an alkyl/alkenyl (or, in the naphthobenzofuran case, a fused benzo ring) at the 6- or 7‑position. They inhibit mammalian 5‑lipoxygenase, preventing metabolism of arachidonic acid to leukotrienes (LTB₄ and the peptido-LTs C₄/D₄), and were tested in human and rat polymorphonuclear leukocyte (PMN) LTB₄ assays. Syntheses use a Diels‑Alder reaction of a 2‑substituted‑1,4‑benzoquinone with 1‑methoxy‑1,3‑cyclohexadiene followed by acid-catalyzed rearrangement (Schemes I–II), with a Skaletzky-based route (Schemes VI–VII) for the trans-fused series. Exemplified compounds include the 7‑propyl‑3‑one, 6‑propyl‑3‑one, 7‑prop‑2‑enyl‑3‑one, 3,8‑dihydroxy‑7‑propyl compounds (3R and 3S), and 3‑phenyl/3‑n‑butyl analogs.

Independent claims — plain language

Claim 1 (compound, Formula I – cis-fused). A hexahydrodibenzofuran-3-ol according to structure STR10, where:

• R₆ is C₁–C₆ straight- or branched-chain alkyl or C₂–C₆ alkenyl; or hydrogen when R₇ is not hydrogen;
• R₇ is hydrogen, C₁–C₆ straight/branched alkyl, or C₂–C₆ alkenyl;
• X and Y either together form a keto (C=O) group, or are different and independently H, OH, C₁–C₆ alkyl, or phenyl — with the proviso that if one of X/Y is alkyl, the other cannot be phenyl;
• plus pharmaceutically acceptable salts.

Claim 2 (compound, Formula II – trans-fused). Same idea but for the trans ring-fusion: R₇ is C₁–C₆ straight/branched alkyl or C₂–C₆ alkenyl, and X/Y are as defined in claim 1 (keto together, or independently H/OH/alkyl/phenyl with the same alkyl-vs-phenyl proviso); plus salts.

Claim 6 (method). A method of inhibiting mammalian leukotriene biosynthesis (or action) by administering a pharmaceutically effective amount of a compound of claim 1.

Claim 7 (method). The same method as claim 6, but using a compound of claim 2.

Claim 10 (method of treatment). A method of treating pulmonary conditions, inflammation, cardiovascular conditions, or skin conditions by administering a pharmaceutically effective amount of a compound of claim 1 to a human in need thereof.

Claim 11 (method of treatment). Same as claim 10, but using a compound of claim 2.

Dependent claims (briefly)

• Claim 3 – narrows claim 1: R₆ = hydrogen / 1‑prop‑2‑enyl / n‑propyl; R₇ = hydrogen / 1‑prop‑2‑enyl / n‑propyl; X/Y as broadly defined.
• Claim 4 – narrows claim 2: R₇ = 1‑prop‑2‑enyl or n‑propyl, and X+Y together = keto.
• Claim 5 – a Markush-style list of 13 specific named species (e.g., hexahydro‑8‑hydroxy‑7‑methyldibenzofuran‑3‑one; 8‑hydroxy‑6‑propyldibenzofuran‑3‑one; 8‑hydroxy‑7‑propyldibenzofuran‑3‑one; various 7‑propyl/7‑prop‑2‑enyl 3,8‑dihydroxy and 3‑phenyl compounds), or their salts.
• Claims 8 and 9 – limit the claim‑6/claim‑7 methods respectively to a human mammal.

Minor internal note

The specification's Examples 6–11 repeatedly refer to "the product of Example 2, Step A," but Example 2 as set out in the patent has only one (unnumbered) step. This appears to be an internal labeling inconsistency in the printed text; I flag it rather than silently correcting it.

Bottom line: This is a 1990 Merck leukotriene-biosynthesis patent (Rupprecht & Boger) that lapsed in 1995 for failure to pay maintenance fees and is now long expired. I found no USPTO litigation/PTAB record and no CAFC (including 2026) docket activity for it, though that conclusion is limited by my search access.

I'll search for litigation records involving US patent 4978679. Let me run several targeted searches.

Let me run additional targeted searches across litigation databases.

Bottom line

No litigation involving U.S. Patent No. 4,978,679 was found. I could not identify any district court action, CAFC appeal, ITC investigation, PTAB/IPR proceeding, or foreign proceeding in which US 4,978,679 was asserted, challenged, or otherwise at issue. I am expressly stating that as a negative finding rather than padding it with near-matches.

Searches performed

I ran open-web searches keyed to the literal identifiers you gave, including:

• US patent 4978679 litigation
• "4978679" patent lawsuit defendant
• "4,978,679" patent infringement lawsuit
• unifiedpatents.com litigation "4978679"
• Merck patent 4978679 leukotriene litigation case
• "Rupprecht" "Boger" patent 4978679 Merck

The Unified Patents litigation portal and PACER were not directly queryable through the tool available to me (only general web search), so I could not run a docket-level keyword sweep of those two databases. That is a real gap in coverage and I flag it below.

What the searches actually returned — and why none of it is responsive

Every hit on the string "4978679" was a false positive. None referred to the patent. Specifically:

1. An unrelated voter-registration file — "4978679 FOX, HALLE KAYE 3241 ROSEDALE AVE" — a Texas SOS voter record, not a patent.
2. A court financial-disclosure record — courtlistener.com/api/rest/v4/investments/4978679/ — an internal CourtListener investment-record database ID, not a patent number.
3. An EU/Swiss product catalogue — item no. 4978679 for a window-fitting product.
4. A Lithuanian corporate registry filing — notice number 4978679.
5. A Florida LLC reinstatement — FEI number 36-4978679.
6. A USFWS public-comment attachment — commenter row number 4978679.
7. DOI 10.1063/1.4978679 — a J. Chem. Phys. erratum DOI (coincidental numeric string).

Separately, US 4,978,679 appears only as a bare citation in unrelated later patents (e.g., EP 3,791,880 A1 by Amarin Pharmaceuticals, which lists it in a long string of incorporated-by-reference 5-lipoxygenase inhibitors, alongside its sibling US 4,975,457). A citation is not litigation.

The likely explanation: the patent had a very short enforceable life

The Google Patents procedural record for US 4,978,679 shows it was granted December 18, 1990 (filed September 25, 1989; inventors Kathleen M. Rupprecht and Joshua S. Boger; assignee Merck & Co., Inc.; priority/application US 07/411,787), and then:

The patent was in force for roughly four years (Dec. 1990 – Dec. 1994) before lapsing. Combined with the fact that no commercial leukotriene-biosynthesis-inhibitor product appears to have been marketed under this patent, there was essentially no window and no product to sue over. This is consistent with the absence of any litigation, and it is the most plausible reason the searches come up empty.

Related litigation you should NOT confuse with this patent

There is a well-known body of leukotriene-related Merck litigation, but none of it involves US 4,978,679:

• Merck Sharp & Dohme Pharms., SRL v. Teva Pharms. USA, Inc., D.N.J. (Chief Judge Garrett E. Brown), Hatch-Waxman trial Feb. 23–26, 2009, opinion Aug. 19, 2009 — concerning US 5,565,473 ("Unsaturated Hydroxyalkylquinoline Acids as Leukotriene Antagonists"), the Singulair®/montelukast patent. Merck prevailed; Teva was found to infringe and was enjoined until the August 2012 expiration.
• Louisiana Wholesale Drug Co. v. Merck & Co., D.N.J. No. 3:09-cv-04050 (filed Aug. 11, 2009) — antitrust/inequitable-conduct challenge to the same '473 patent.
• The later Singulair product-liability litigation (e.g., Bueno v. Merck, S.D. Cal. No. 3:22-cv-00522) — not a patent case at all.

I am deliberately not treating 5,565,473 as 4,978,679; they are different patents, different numbers, different inventors, different subject matter (a quinoline acid LTD₄ antagonist versus a hexahydrodibenzofuranol 5-lipoxygenase inhibitor).

Caveats

• Negative finding, not a certified clearance. I did not get direct docket-level access to PACER, Docket Alarm, or the Unified Patents litigation portal, so I cannot rule out a pre-1995, never-digitized complaint, or a case in which 4,978,679 was a tangential patent among many asserted.
• Old records are thin. For a patent that expired in 1994–95, the relevant complaints would predate routine electronic docketing for many districts, so paper-only records may exist that are not web-indexed.
• Family members. The same disclosure was filed as CA 2025479 A1, JP H03184969 A, and EP 0420571 A2/A3. I found no opposition, appeal, or revocation proceeding for any of them either — though again, this is based on open-web search only, and I do not have direct access to EPO opposition files or JPO records.
• Outcome/status fields: Because I found no cases, I have no plaintiff, defendant, jurisdiction, case number, filing date, or outcome to report. Reporting any such fields would require fabrication.

If you need a definitive answer, the next step would be a direct PACER/Unified Patents/Docket Alarm search restricted to the exact patent number, plus a request to the patentee's successor (Merck) for any enforcement history — I could not complete that here.

I'll verify the structured data against public sources before reporting.

PTAB proceedings overview

Total AIA trial proceedings on file for US 4,978,679: 0 — zero IPRs, zero PGRs, zero CBMs; nothing instituted, nothing denied, nothing settled, nothing appealed. The USPTO Open Data Portal returns no AIA trial proceedings for this patent, and my independent web searches (Google Patents family/citation data, docket aggregators, PTAB decision text) surfaced no petition, institution decision, Final Written Decision, or Federal Circuit appeal naming US 4,978,679. The bottom-line defensive posture is therefore not "hardened patent" and not "claims canceled by the Board" — it is something a defendant should find far more useful: the patent is dead, and it died from non-payment of a maintenance fee, not from a PTAB trial.

Proceedings overview (expanded — why the per-proceeding format is empty)

There are no proceedings to list. Because the instructed template assumes at least one proceeding, the correct analytical move is to explain why the list is empty and what that means, using the legal-status record on the patent's own face:

Three structural reasons explain the absence of PTAB activity, in descending order of importance:

1. The patent lapsed in 1994–1995 for failure to pay the maintenance fee — roughly 30 years before today. It published 1990-12-18 and was enforceable for only about four years. There was no commercial window in which a competitor needed an IPR: the claimed hexahydrodibenzofuran-3-ols were in the public domain, and the disclosed compounds appear never to have been commercialized by Merck as a marketed product (Merck's marketed 5-lipoxygenase inhibitor is zileuton/ZYFLO, a different chemical series).
2. AIA trial types are largely unavailable as a matter of law. PGR is available only for patents with an effective filing date on or after 2013-03-16 — this patent's effective filing date is 1989-09-25, so no PGR. CBM review was limited to covered business method patents (financial products/services) and sunset on 2020-09-16 — a chemical-compound claim is not a CBM, and the window has closed regardless. Only IPR was ever theoretically available, and IPR against a patent that lapsed for fee non-payment in 1995, with no live infringement dispute, offers no petitioner any benefit — you cannot obtain a damages defense for conduct that predates the lapse, and an FWD would give no forward-looking freedom to operate.
3. The parallel foreign family is equally quiet. The same subject matter was pursued as CA 2,025,479 A1 (abandoned), JP H03-184969 A (pending), and EP 0 420 571 A2/A3 (withdrawn). The European case was withdrawn at the search/A3 stage rather than prosecuted to grant or opposed — consistent with the U.S. case being abandoned commercially when the maintenance fee went unpaid.

The structured "PTAB proceedings on file" block is the canonical list and it says none. Nothing I found on the web contradicts it, so I am not flagging any unindexed or recently filed proceeding.

Strategic summary

Claim status: neither canceled nor sustained — simply never tested, and now unenforceable. US 4,978,679 issued with 11 claims: claim 1 (genus of Formula I), claim 2 (genus of Formula II), claims 3–4 (narrowed genera), claim 5 (a Markush list of 14 named species), and claims 6–11 (method claims for inhibiting leukotriene biosynthesis/action and for treating pulmonary, inflammatory, cardiovascular, or skin conditions). Because no IPR, PGR, or CBM ever reached a Final Written Decision, no claim of this patent has been canceled, confirmed, or construed by the Board. There is no claim-level disposition to quote, and I will not invent one. The claims were never narrowed in an AIA trial; they simply expired unenforced. Note the drafting irregularities that would have mattered had anyone litigated: claim 1 opens with "R₆ is: (C₁-C₆)-straight or branched chain alkyl or (C₂-C₆)-alkenyl; and hydrogen, when R₇ is not hydrogen," and claim 5 mixes "(4aS*,9bS*,3R*)" and "(4aS*,9bS*,3S*)" designations with a recitation of "(4aR*,9bS*,3S*)-3,8-dihydroxy…" species that the specification's Example 12–17 chemistry reaches through the trans-fused (4aR*,9bS*) route — quirks that would have been grist for a § 112 or indefiniteness attack. None of that was ever adjudicated.

Estoppel landscape: none exists, and it doesn't matter. § 315(e)(2) estoppel attaches only to a petitioner that obtained an FWD; there is no petitioner and no FWD, so no one is estopped from anything. If you were trying to map out "which prior-art grounds remain available," the answer is that the question is academic: the patent's last day of enforceable term was 2009-09-25, and in reality its enforceable life ended in 1995. There are no live grounds to preserve because there is no live patent. If you nonetheless want the art of record, the examiner cited only seven references — US 3,317,527 and US 3,496,181 (Skaletzky/Upjohn, the very synthesis chemistry the specification relies on), US 3,803,180 and US 3,931,288 (Hoffmann-La Roche), FR 2,472,569 (Cerm/Centre Européen de Recherches Mauvernay), EP 0 067 769 (Riom Laboratoires), and US 4,857,516 (Takeda) — plus 13 non-patent citations including Birch & Powell (Tetrahedron Lett. 1970, 3467), Birch et al. (J. Chem. Soc. 1964, 2932), Brannock et al. (J. Org. Chem. 29, 2579 (1964)), Takahashi et al. (Tetrahedron Lett. 23, 4361 (1982); 24, 3489 (1983)), Powell (Tetrahedron Lett. 1970, 3463), and Greenlee et al. (Tetrahedron Lett. 24, 4559 (1983)).

Pattern signals: none, and that is itself the signal. No serial petitioner, no defensive aggregator (no Unified Patents, RPX, or similar entity anywhere in the record), no patent-owner appeal activity — the patent owner here is Merck & Co., Inc. (assignment recorded 1990-09-24, reel/frame 005458/0352), an operating company that let the case lapse and never asserted it. The only forward citations are EP 0 751 137 / FR 2 736 052 (Egis, oxaindene derivatives), EP 3 791 880 (Amarin, EPA compositions — cited as background art in a 2021 patent), and CN 116715643 (五邑大学, a 2023 preparation method for hydrogenated dibenzofuran compounds). These are bibliographic citations in later patents, not litigation or trial events. Modern PTAB practice notwithstanding — the Board will institute on an expired patent where a petitioner shows a reasonable likelihood of prevailing and an actual controversy exists — nobody files an IPR against a 1989-priority chemical genus that has been unenforceable since the Clinton administration.

Recommended next steps

• If you are a defendant: stop. If a demand letter from any entity cites US 4,978,679, that is close to dispositive evidence that the sender has not done basic diligence. The patent lapsed for failure to pay maintenance fees on 1994-12-18 (effective 1995-12-21) and its term ended 2009-09-25. Asserting it against conduct occurring today is not merely "sanction-bait" in the IPR sense — it is the assertion of a patent that cannot be infringed because it is not in force, and a Rule 11 exposure. Verify status on USPTO Patent Public Search / PatentCenter before responding on the merits, and preserve the fee-lapse transaction history as the core exhibit.
• Do not budget for an IPR. There is no proceeding to monitor, no institution deadline, no 1-year statutory trial clock, no oral hearing, and no FWD due date. There is no § 315(b) one-year bar clock running on anyone, and no § 315(e) estoppel to plan around. Filing an IPR against this patent would be a pure cost with no downside-protection benefit.
• The absence of PTAB activity here is not the usual "well-asserted patents eventually attract IPRs" signal — invert it. For a patent of this vintage with zero AIA filings, the correct inference is not "the patent is a hardened survivor." It is that the patent was never commercially valuable enough to assert or to challenge. Contrast the surrounding Merck/related disclosures in the same field (e.g., US 4,966,907 and US 4,977,457, cited on the patent's own "Similar Documents" list), which belong to the same 5-lipoxygenase program era — a reminder that in this series the litigation value lived in the successor antagonist patents (montelukast), not in these 5-LO inhibitor genera.
• Confirm the negative before relying on it. The canonical sources to re-check are the USPTO PTAB E2E / PTAB public-information portal, Docket Alarm's PTAB coverage, and Google Patents US4978679A for the legal-events tab. My searches returned no trial proceeding; if a newly filed petition ever appeared, it would be a first-of-its-kind filing against a patent that has been unenforceable for three decades, and I would treat such a filing as itself an indicator of unusual behavior by the petitioner.

Confidence note. I have high confidence in two things: (1) the structured ODP block reports zero proceedings, and (2) the patent lapsed for maintenance-fee non-payment in 1994/1995 and expired 2009-09-25. I have moderate-to-high confidence that no PTAB proceeding ever existed, based on multiple independent web searches; I could not query PTAB E2E directly from this environment, so a docket-level confirmation on ptacts.uspto.gov is the one remaining diligence step. I have not located and will not speculate about any district-court litigation history, which is outside the scope of what was asked but may be worth a separate PACER/Docket Alarm check if a demand letter has actually crossed your desk.

I'll start by verifying the assignment records and checking for any litigation or NPE activity.

Let me verify the assignment record directly and check for any post-Merck transfers or litigation.

Let me check the correspondent of record and look for any litigation or enforcement activity.

Assignment Record Reconstruction — US 4,978,679

Patent: 6- and/or 7-substituted-1,2,3,4,4a,9b-hexahydro-8-hydroxydibenzofuran-3-ols as inhibitors of leukotriene biosynthesis
App. No.: 07/411,787 · Filed: 1989-09-25 · Issued: 1990-12-18 · Assignee of record: Merck & Co., Inc.

Sourcing note (read before relying on this): I could not open the USPTO Assignment Center (https://assignmentcenter.uspto.gov/) or the legacy assignment.uspto.gov interface directly in this session, and my retrieval budget was exhausted before I could pull the Assignment Center record itself. Everything below is reconstructed from the Google Patents legal-events mirror of the same USPTO assignment data, which exposes the reel/frame and conveyance but not the correspondent-of-record field. Where the instructions call for the correspondent, I say so rather than guess. All reel/frame and date citations should be re-verified against the Assignment Center by patent number before being relied on.

Inventors

Unusual-pattern finding: the application was filed 1989-09-25 but the inventors' assignment to Merck was not executed until 1990-09-19 / 1990-09-20 and recorded 1990-09-24 — roughly 12 months after filing and under 3 months before issuance. This is a classic at-issue / confirmatory assignment rather than a filing-date assignment, and it was signed by Boger after he had already left Merck to run Vertex. That combination (delayed execution + signer no longer an employee) is worth flagging, but in this case it is not a precursor to a portfolio fire-sale — see the timeline.

Original assignee

Merck & Co., Inc. (Rahway, NJ) — named on the face of the patent and the sole recorded assignee for the entire life of the patent.

• Line of business: global research-based pharmaceutical company; this patent sits in the company's 1980s–1990s immunology/inflammation and 5-lipoxygenase inhibitor research program.
• Product embodying the claims: None that I can identify. The claims are directed to a specific hexahydrodibenzofuran-3-ol chemotype, not to a marketed drug. Merck's approved 5-LO/leukotriene-pathway products of that era were Singulair (montelukast, a CysLT1 antagonist, different chemotype**)** — I found no evidence that any compound of Formula I / Formula II in this patent was ever commercialized.
• Corroborating tell: Merck declined to pay the first maintenance fee. The patent lapsed and expired in 1995, about four years after issuance — the opposite of the behavior you see when a company is protecting a commercial product. Had the fee been paid, the term would have run to 2009-09-25.
• Current status: operating; Merck & Co., Inc. remains a going concern (now Rahway/Kenilworth, NJ). No bankruptcy, no dissolution, no IP-holding spin-out of this asset.

Assignment timeline

Chronological list of every recorded assignment. There is exactly one.

• 1990-09-19 to 1990-09-20 (executed) / recorded 1990-09-24 — Reel 005458 / Frame 0352
  • Conveyance: Assignment of assignors' interest (original employment/confirmatory assignment of patent rights)
  • Assignor: Kathleen M. Rupprecht and Joshua S. Boger (joint assignors; signing dates 1990-09-19 to 1990-09-20 per the USPTO assignment abstract)
  • Assignee: Merck & Co., Inc., Rahway, New Jersey (large entity)
  • Correspondent: Not exposed by the data source available to me. Google Patents' legal-events mirror for this record shows only the conveyancing line, the assignors, the reel/frame, and the signing dates — the "correspondent / attorney of record" field is not reproduced. This is the one field the NPE analysis below would most like to have, and I am flagging its absence rather than filling it in. (For scale, however, Merck's 1980s–90s assignments of this type were typically recorded through Merck's own in-house patent department at Rahway — but that is context, not a record citation, and I am not asserting it as the correspondent here.)
  • Context: At-issue / confirmatory assignment of the inventors' rights to their employer; not an acquisition, not a sale, not a securitization.

Post-issuance chain: none. No assignment, security agreement, merger, change of name, license, release, or correction was ever recorded against US 4,978,679 after reel 005458/0352. The remaining entries in the legal-events record are all administrative, not conveyances:

• 1990-12-08 / 1991-12-05 — FEPP payer-number administrative entries (large-entity fee status). Not conveyances.
• 1994-07-26 — Maintenance fee reminder mailed.
• 1994-12-18 — Lapsed for failure to pay maintenance fees.
• 1995-02-28 — Recorded as lapsed; effective date 1995-12-21.
• 2018-01-28 — Bulk status update confirming expiration for nonpayment (37 CFR 1.362).
• 2009-09-25 — Anticipated (not actual) expiration date from the 20-year term.

Family status (same priority date, for completeness): CA 2025479 A1 — abandoned; EP 0420571 A2/A3 — withdrawn; JP H03-184969 A — filed, shown as pending/active in the Google Patents record. Every member of the family was allowed to die on the patent side or was never pushed through to grant. That is consistent with a research-stage chemotype that Merck abandoned: no foreign filings were maintained and no US maintenance fee was paid.

Because there are no post-issuance transfers beyond the original inventors→Merck assignment, the remaining NPE sections resolve to negatives. I continue below as instructed rather than stopping, since the single original assignment is itself the finding.

Timeline diagram

timeline
    title Ownership of US 4978679
    1989 : Application filed by Rupprecht and Boger
         : Boger founds Vertex after leaving Merck
    1990 : Inventors assign rights to Merck and Co Inc
         : Patent issues as US 4978679
             : Recorded at Reel 005458 Frame 0352
    1994 : First maintenance fee reminder mailed
         : Merck lets fee lapse in December
    1995 : Patent expires for nonpayment
    2018 : Status record updated as expired

(If the nested third line under 1990 does not parse in your renderer, delete it — the two events above it carry the same information.)

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The patent never left Merck. The only recorded conveyance is inventors→Merck at reel 005458/0352 (recorded 1990-09-24). No "IP / Patents / Licensing / Holdings / Ventures" entity appears anywhere in the record, and there is no registered-agent address or single-purpose LLC to point at.

2. Known asserter in the chain — not present. The sole assignee is Merck & Co., Inc. No entity from the listed NPE rosters (Acacia, Marathon, IV, IPNav, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities) appears as assignee, assignor, or party on any recorded link for this patent. I also found no litigation naming US 4,978,679 in the searches I was able to run — treat that as "none found," not as a certified negative, since I could not run a full Docket Navigator / CourtListener sweep.

3. Repeat correspondent across the chain — not present (and not verifiable). With exactly one recorded assignment there can be no recurrence by definition. I additionally could not retrieve the correspondent name for that single record (see the sourcing note), so I cannot tell you who filed reel 005458/0352. Nothing here supports a repeat-player-attorney finding, and I am not going to manufacture one.

4. Cascading transfers — not present. One assignment, executed 1990-09-19/20, recorded 1990-09-24. There is no chain of LLCs, no sequence of transfers, and no <24-month cascade. The relevant dates are 27 years apart from any plausible assertion window.

5. Pre-litigation transfer — not present. No infringement suit naming this patent was identified. The only assignment is dated ~3 months before issuance, which is a prosecution-stage event, not a pre-suit venue/standing arrangement.

6. Bankruptcy fire-sale — not present. Merck & Co., Inc. never filed Chapter 7 or 11. The asset died by a different mechanism: Merck simply declined to pay the first maintenance fee, reminder mailed 1994-07-26, lapse recorded 1994-12-18. This is affirmative abandonment by an operating company, not a distressed sale.

7. Privateering — not present. There is no downstream NPE and therefore no entity for Merck to have been asserting through. No SEC-disclosed divestiture or Patent Progress / EFF coverage connects this patent to an assertion campaign.

8. Defensive aggregator — not present. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at the original operating assignee, and then at expiry. Note the inverse of this signal applies loosely — the patent was neutralized, but by Merck's own fee lapse, not by a defensive purchase.

Verdict

Insufficient data — in the specific sense defined here ("no records, or only the original assignment"). Only one assignment is recorded: inventors Rupprecht and Boger → Merck & Co., Inc., reel 005458/0352, executed 1990-09-19/20, recorded 1990-09-24. No post-issuance transfer of any kind exists, so there is no chain to analyze for NPE structure.

To be clear about what that label does not mean: the NPE question here is affirmatively negative, not ambiguous. The patent stayed with its original operating-company assignee for its entire life, was never asserted, was never commercialized, and Merck let it lapse for nonpayment of the first maintenance fee (reminder 1994-07-26; lapse 1994-12-18; expiry recorded 1995-02-28), roughly four years after issuance. The only notable ownership-adjacent pattern is on the inventor side, not the assignee side: Joshua S. Boger left Merck in 1989 to found Vertex Pharmaceuticals, and the confirmatory assignment to Merck was not executed until September 1990, after his departure. There is no shell entity, no known asserter, no cascading LLC chain, no bankruptcy sale, and no defensive aggregator in this record.

Verify at:

• USPTO Assignment Center — search patent number 4978679: https://assignmentcenter.uspto.gov/
• Legacy Assignment Search (same underlying records): https://assignment.uspto.gov/patent/index.html
• Google Patents legal events / family status: https://patents.google.com/patent/US4978679/en

Open items a paid database would close: (a) the correspondent-of-record on reel 005458/0352, which the free mirror does not expose; (b) a full CourtListener / Docket Navigator adversary check to convert "no litigation found" into a certified negative; (c) confirmation from Merck's 10-K/8-K history that no divestiture of the 5-LO chemotype ever occurred (I found no such filing, but I could not complete that search).

I'll research this systematically. Let me search for the patent and its cited prior art references.

Let me research the individual cited patents in detail.

Prior-Art Analysis — U.S. Patent No. 4,978,679

1. Confirmation of the patent

The patent claims two genus formulas (I and II) covering 6‑ and/or 7‑substituted‑1,2,3,4,4a,9b‑hexahydro‑8‑hydroxydibenzofuran‑3‑ols, and methods of inhibiting leukotriene biosynthesis. Source: Google Patents, https://patents.google.com/patent/[US4978679A](/patent/US4978679A)/en.

Important interpretive caution: The numbers below are reproduced exactly as they appear on the face of US 4,978,679 and in its Google Patents "Citations" record. I did not auto-correct any identifier. Where my independent verification of a reference's content was weak (older/hard-to-retrieve records), I say so explicitly.

2. Prior art cited on the face of US 4,978,679

The patent lists seven patent documents and several journal articles under "References Cited." The seven patent documents are the items the Examiner "considered to be relevant," so these are the references to evaluate for §102 anticipation.

2.1 US 3,317,527 — Skaletzky et al. (Upjohn Co.), granted 1967‑05‑02

• Citation as listed: "3,317,527 5/1967 Skaletzky et al. … 260/473 G"
• Description: Benzofuranol chemistry (3‑substituted benzofuranols/related 2,3‑dihydrobenzofuran systems). The specification of US 4,978,679 expressly relies on the Skaletzky work (US 3,317,527, 3,337,563, 3,496,181) as the synthetic route to the trans (Formula II) dibenzofuran framework. It is a process/chemistry reference, not a compound-utility reference.
• §102 relevance: Would not anticipate. It discloses a different structural class and utility. Its role is as enabling background art for one synthetic route (potential §112/enablement context, not §102).

2.2 US 3,496,181 — Upjohn Co., granted 1970‑02‑17

• Title: "2‑Aminocycloalkyl hydroquinones, esters, ethers and N‑oxides thereof, and a process for preparing the same."
• Description: Aminocycloalkyl hydroquinone intermediates (verified via FreePatentsOnline class listing; also corresponds to UK 1,197,602, Upjohn, published 27 Sep 1967).
• §102 relevance: Would not anticipate any claim. The compounds are hydroquinone/aminocycloalkyl intermediates — no dibenzofuran ring system, no 8‑hydroxy‑3‑ol substitution pattern, no leukotriene utility.

2.3 US 3,803,180 — Berger et al. (Hoffmann‑La Roche Inc.), granted 1974‑04‑09

• Title: "Tricyclic compounds." (Listed as "L Berger"; prior art date 1971‑03‑26.)
• Description: Tricyclic (dibenzofuran‑type) compounds asserted by the patentee to be "anti‑inflammatory and antirheumatic agents." Verified record exists (Google Patents US3803180A; Europe PMC listing).
• §102 relevance: Closest of the "utility" references on the face of the patent (anti‑inflammatory tricyclics), but it does not disclose the specific 6‑/7‑alkyl or ‑alkenyl‑8‑hydroxy‑1,2,3,4,4a,9b‑hexahydro‑dibenzofuran‑3‑ol compounds, nor their use as 5‑lipoxygenase/leukotriene‑biosynthesis inhibitors. Not anticipatory; relevant only under §103 as background showing the scaffold's anti‑inflammatory activity.

2.4 US 3,931,288 — Hoffmann‑La Roche Inc., granted 1976‑01‑06

• Title (as recorded): "Alkyl esters of 4‑chlorophenoxy‑4‑oxo‑cycloalkyl‑carboxylic acid."
• Description: Listed by the patentee together with US 3,803,180 as anti‑inflammatory/antirheumatic art.
• §102 relevance: Structurally unrelated to the claimed dibenzofuran‑3‑ols. No anticipation. Background/§103 only.

2.5 US 4,857,516 — Terao et al. (Takeda Chemical Industries), granted 1989‑08‑15

• Title: "Coumaran derivatives and their pharmaceutical use." (Prior art date 1986‑12‑27.)
• Description: Coumaran (2,3‑dihydrobenzofuran) derivatives. This is the most recent U.S. patent cited on the face of the patent.
• §102 relevance: Coumarans are bicyclic (fused benzene + dihydrofuran), whereas the claims require a tricyclic hexahydrodibenzofuran (the third cyclohexane ring fused at 4a,9b). No anticipation. Potential §103 reference only if it disclosed the relevant utility/substitution (it is directed to 2,3‑dihydrobenzofurans, not hexahydrodibenzofurans).

Foreign patent documents

2.6 FR 2,472,569 A1 — Centre Européen de Recherches Mauvernay ("Cerm"), published 1981‑07‑03

• Description: Hexahydro‑4‑hydroxy‑dibenzofuran derivatives "useful as intermediates for analgesic 4‑amino compounds."
• §102 relevance: This is chemically the closest structural reference on the face of the patent — it discloses the hexahydrodibenzofuran core. However, it is directed to 4‑hydroxy/4‑amino (position‑4a‑type) analgesics as intermediates, not to 6‑/7‑substituted‑8‑hydroxy‑3‑ols with 5‑lipoxygenase activity. It does not disclose the claimed substituent pattern (R₆/R₇ = C₁–C₆ alkyl/alkenyl at the 6/7 positions; 3‑ol; 8‑OH) and would not anticipate under §102.

2.7 EP 0,067,769 A1 — Riom Laboratoires – C.E.R.M., published 1982‑12‑22

• Title: "1,2,3,4,4a,9b‑Hexahydro‑4a‑piperazinylmethyl‑4‑dibenzofuranones or substituted 4‑dibenzofuranoles, process for their preparation and their therapeutic use."
• Description: Antibronchoconstrictor hexahydrodibenzofurans bearing a 4a‑piperazinylmethyl group.
• §102 relevance: Same scaffold family, but the defining substituents (4a‑piperazinylmethyl; 4‑one/4‑ol) are different from the claimed 6‑/7‑substitution and 8‑hydroxy‑3‑ol pattern. Not anticipatory; the nearest §103-type art among the foreign documents.

3. The most relevant prior art: US 4,769,387 (Abbott)

Although it appears in Google Patents only under "Family Cites Families" (not on the printed face of the patent in the excerpt provided), US 4,769,387 (Abbott Laboratories), granted 1988‑09‑06, priority 1987‑11‑13, "Dibenzofuran lipoxygenase inhibiting compounds, compositions and use" is plainly the most technically relevant reference.

• Description (verified): 5‑ and/or 12‑lipoxygenase inhibiting dibenzofuran compounds of the general formula bearing N‑hydroxyurea / N‑hydroxyacetamide / hydroxamic‑acid (hydroxylamine) side chains, e.g., "N‑hydroxy‑N‑(1‑dibenzofur‑3‑ylethyl) urea." Utility is the treatment of asthma, allergy, arthritis, psoriasis and inflammation — i.e., the same biological target and disease space as US 4,978,679.
• §102 relevance: This is the reference that establishes the motivation/expectation that dibenzofuran-based compounds inhibit 5‑lipoxygenase. But it discloses a fully aromatic dibenzofuran with a hydroxylamine/hydroxamic side chain, not the claimed hexahydro‑8‑hydroxy‑dibenzofuran‑3‑one/3‑ol core. It therefore does not anticipate any claim of US 4,978,679 under §102; it is the key §103 reference (combined with the hexahydrodibenzofuran scaffold art of FR 2,472,569 / EP 0,067,769).

4. Non‑patent literature cited

The face of the patent cites (all as background to the synthetic chemistry / structural class):

• A. J. Birch and V. H. Powell, Tetrahedron Letters 1970, 3467–3470.
• A. J. Birch et al., J. Chem. Soc. 1964, 2932–2941.
• K. Brannock et al., J. Org. Chem. 29, 2579 (1964).
• T. Takahashi et al., Tetrahedron Letters 23, 4361–4364 (1982).
• T. Takahashi et al., Tetrahedron Letters 24, 3489–3492 (1983).
• V. H. Powell, Tetrahedron Letters 1970, 3463–3466.
• W. J. Greenlee et al., Tetrahedron Lett. 24, 4559–4560 (1983).

These are synthesis/structure papers (Birch reduction, Diels–Alder/cyclohexadiene chemistry) — they support the syntheses described in Schemes I–VII and are not §102 art against the compound claims.

Additional art surfaced in the corresponding EP search report (EP 0,420,571 A3):

• M. L. Hammond et al., "2,3‑Dihydro‑5‑benzofuranols as antioxidant‑based inhibitors of leukotriene biosynthesis," J. Med. Chem. 1989, 32(5), 1006–1020 — cited as category "A" against claims 1, 2, 6, 7, 9, 10. This is the utility-closest NPL: dihydrobenzofuranols as leukotriene‑biosynthesis inhibitors, but again a bicyclic (not hexahydro‑tricyclic) core.
• The EP search report also lists US‑A‑4,769,387 (the Abbott reference above) as a category‑A document against claims 1, 2, 6, 7, 9, 10.

5. §102 anticipation assessment — summary

Bottom line on §102: No reference cited on the face of US 4,978,679 (or surfaced in the EP search report) discloses, in a single reference, every element of any claim. The independent compound claims (1 and 2) require the tricyclic hexahydro‑8‑hydroxydibenzofuran‑3‑one/3‑ol core with defined 6‑/7‑alkyl or ‑alkenyl substitution; the closest references either (a) use a different ring system (bicyclic dihydrobenzofurans — US 4,857,516; Hammond), (b) use the same hexahydrodibenzofuran core but with incompatible substituents/utility (FR 2,472,569; EP 0,067,769), or (c) teach the same utility/target on a different scaffold (US 4,769,387). Accordingly, the cited art is §103 (obviousness) art, not §102 anticipatory art. The dependent claims (3–5) and the method claims (6–11) are, a fortiori, not anticipated.

6. Caveats and confidence

• The patent identity and bibliographic data are verified (Google Patents and the issued‑patent PDF).
• Descriptions of US 3,803,180, US 4,769,387 and US 4,857,516 are verified from retrieved records.
• Descriptions of US 3,317,527, US 3,496,181, US 3,931,288, FR 2,472,569 and EP 0,067,769 come primarily from the patentee's own summary statements plus partial verification; the raw text of some pre‑1970 records was noisy in retrieval, so treat the one‑line characterizations of those as medium confidence.
• I did not auto‑correct any patent number. Note that Google Patents lists the second U.S. reference as US 3,496,181 A, while the printed patent column‑56 listing excerpt shows 3,317,527 first — both are consistent with the "References Cited" block; no discrepancy was altered.
• The §102 conclusions rest on the claim language of US 4,978,679 as published. This is a technical prior‑art analysis, not a legal opinion or a validity determination.

Primary sources:

• US 4,978,679 (Google Patents): https://patents.google.com/patent/US4978679A/en
• US 4,978,679 issued PDF: https://patentimages.storage.googleapis.com/49/fc/8b/3d122c6c0b557b/US4978679.pdf
• EP 0,420,571 A3 (search report): https://patentimages.storage.googleapis.com/5f/7c/85/be3a19c801ad36/EP0420571A3.pdf
• US 4,769,387 (Google Patents): https://patents.google.com/patent/US4769387
• US 3,803,180 (Google Patents): https://patents.google.com/patent/US3803180

I'll start by verifying the key prior-art references cited on the patent page, then build the § 103 analysis.

Let me verify the remaining cited references and the closely-related sibling Merck applications.

Obviousness Analysis — U.S. Patent No. 4,978,679 (35 U.S.C. § 103)

Patent: "6- and/or 7-substituted-1,2,3,4,4a,9b-hexahydro-8-hydroxydibenzofuran-3-ols as inhibitors of leukotriene biosynthesis"
Inventors: Rupprecht, K. M.; Boger, J. S. Assignee: Merck & Co., Inc.
U.S. Filing/Priority: 1989‑09‑25. Granted: 1990‑12‑18.
Statutory basis used: all cited art predates the 1989‑09‑25 U.S. filing and is available under § 102(a)/(b).

Scope note / limitations on my analysis. This assessment is built from the "Citations" (7 patent references), "Non-Patent Citations," and "Family Cites Families (1)" sections of the supplied patent page, supplemented by verification searches. I obtained full or partial text for US 4,769,387A, US 4,857,516A, US 3,803,180A, FR 2 472 569A1, and US 4,978,679A. For US 3,317,527A, US 3,496,181A, and EP 0 067 769A1, my search was truncated, so I rely on the titles of record and the patent's own characterization of them; where I do so I flag it. I did not find a single reference that identically discloses any claimed species, so this is a § 103 (not § 102) case.

1. The claimed subject matter

The structural core of every claim is: (i) the hexahydrodibenzofuran tricycle, (ii) a phenolic OH at the 8-position, (iii) an aliphatic O-function (OH or =O) at the 3-position, and (iv) a small alkyl/alkenyl group at C‑6 or C‑7. The only stated utility is 5-lipoxygenase inhibition to suppress leukotriene biosynthesis.

2. The prior art of record

A. US 4,769,387A — Abbott Laboratories (priority 1987‑11‑13; issued 1988‑09‑06). "Dibenzofuran lipoxygenase inhibiting compounds, compositions and use." This is the closest art and is expressly a family-cited reference. It discloses 5- and/or 12-lipoxygenase-inhibiting dibenzofurans of the formula:

R¹ = H, C₁–C₄ alkyl, C₂–C₄ alkenyl, or NR²R³; X = O/S/SO₂/NR⁴; A = C₁–C₆ alkylene or C₂–C₆ alkenylene; Y at each occurrence = H, halogen, hydroxy, cyano, C₁–C₁₂ alkyl, C₂–C₁₂ alkenyl, … aryl, etc.; M = H or cation.

The reference states the compounds are "potent inhibitors of 5- and/or 12-lipoxygenase" and are useful for "asthma, allergy, arthritis, psoriasis, and inflammation." In other words, the exact heterocyclic pharmacophore claimed here — a dibenzofuran bearing hydroxy and C₁–C₄ alkyl/C₂–C₄ alkenyl substituents, used as a 5-lipoxygenase inhibitor for the same diseases — is squarely disclosed.

B. US 4,857,516A — Takeda (priority 1986‑12‑27; issued 1989‑08‑15). "Coumaran derivatives and their pharmaceutical use." Discloses 3-substituted coumarans (i.e., 2,3-dihydrobenzofurans) and states they exert "inhibition or control of 5-lipoxygenase which is a key enzyme for the biosynthesis of leukotrienes," plus antiallergic and cardiovascular utility. Takeda's sibling EP 0 273 647A1 ("5-hydroxy-2,3-dihydrobenzofuran analogs as leukotriene biosynthesis inhibitors," same priority) is cited in the record. This teaches that the two-ring substructure of the claimed tricycle, bearing a phenol OH (the 5-OH of the coumaran = the 8-OH of the dibenzofuran), is itself a leukotriene-biosynthesis inhibitor.

C. FR 2 472 569A1 — C.E.R.M. / Mauvernay (1979‑12‑31). "1,2,3,4,4a,9b-Hexahydro-4-hydroxy-dibenzofurans and process for their preparation," useful as intermediates for analgesic 4-amino compounds. Discloses the exact tricyclic hexahydrodibenzofuran core bearing an aliphatic ring hydroxyl, with variable R¹–R⁴ (H, halogen, lower alkyl, lower alkoxy, CF₃) on the aromatic ring — i.e., it teaches both the scaffold and 6/7-type aromatic substitution.

D. US 3,803,180A — Hoffmann-La Roche / L. Berger (priority 1971‑03‑26). "Tricyclic compounds." Dibenzofuran/dibenzothiophene carboxylic acids and esters "useful as anti-inflammatory and anti-rheumatic agents." Teaches the inflammatory-disease utility of the dibenzofuran ring system.

E. EP 0 067 769A1 — Riom Laboratoires / C.E.R.M. (1981‑06‑12). "1,2,3,4,4a,9b-Hexahydro-4a-piperazinylmethyl-4-dibenzofuranones or substituted 4-dibenzofuranoles," described in the patent's own background as antibronchoconstrictors (i.e., respiratory therapy). By title, this teaches the hexahydrodibenzofuran ring bearing an aliphatic ketone (4-one) or alcohol (4-ol) — the direct structural analogue of the claimed 3-one/3-ol. (Content inferred from the title of record; full text not retrieved.)

F. US 3,317,527A and US 3,496,181A — Upjohn / Skaletzky (1967; 1970). Benzofuranols and 2-aminocycloalkyl hydroquinones. These are the very references the specification cites (as "Skatelzky") for preparing the trans-fused Formula II skeleton, so they are admitted enabling art for the ring system and its chemistry. (Content inferred from title; consistent with the specification's own citation.)

G. Non-patent literature: Birch & Powell, Tetrahedron Lett. 1970, 3463–3466 and 3467–3470; Birch et al., J. Chem. Soc. 1964, 2932–2941; Brannock et al., J. Org. Chem. 29, 2579 (1964); Takahashi et al., Tetrahedron Lett. 23, 4361–4364 (1982) and 24, 3489–3492 (1983); Greenlee et al., Tetrahedron Lett. 24, 4559–4560 (1983). These establish that the Diels–Alder/acid-rearrangement route to hexahydrodibenzofurans and related tricycles (the specification's Scheme I chemistry) was well-known, routine methodology years before the filing date.

3. Level of ordinary skill

A person of ordinary skill would hold an advanced degree in organic or medicinal chemistry plus several years of pharmaceutical R&D experience, and would be conversant with (a) the arachidonic-acid cascade, 5-lipoxygenase and the leukotrienes; (b) structure–activity relationships in the dibenzofuran/benzofuran/coumaran series; and (c) standard transformations (Diels–Alder, Claisen rearrangement, hydride and Grignard reductions, cyanohydrin chemistry) — all of which the specification itself employs as routine steps.

4. Differences between the claims and the prior art

The only differences between the claimed compounds and the closest art are conventional, and each element is separately disclosed:

1. Ring saturation. US 4,769,387A discloses aromatic dibenzofurans; the claims require the hexahydro (partially saturated) ring. FR 2 472 569A1, EP 0 067 769A1, US 3,317,527A and US 3,496,181A each disclose the hexahydro (or tetrahydro) ring system. Saturation of a known aromatic ring system to its known hydro counterpart is a routine, predictable modification.
2. 3-OH/=O. EP 0 067 769A1 teaches the 4-one/4-ol (the aliphatic oxygen function); FR 2 472 569A1 teaches the aliphatic 4-OH. The claimed 3-ol/3-one is the same functionality at an equivalent ring position.
3. 8-OH. Takeda's coumarans (US 4,857,516A / EP 0 273 647A1) teach that the corresponding phenolic OH is the 5-lipoxygenase-relevant group; US 4,769,387A lists "hydroxy" as a Y substituent.
4. 6/7 alkyl/alkenyl. US 4,769,387A expressly lists C₁–C₄ alkyl and C₂–C₄ alkenyl as R¹ and C₁–C₁₂ alkyl/C₂–C₁₂ alkenyl as Y; FR 2 472 569A1 teaches aromatic-ring alkyl/alkoxy substitution. n-Propyl and allyl are the simplest members of those lists (allyl being the classic Claisen handle the specification itself uses).

In short, every claimed structural element appears, individually, in the prior art of record; the claims combine only known elements in a known way.

5. Combinations that render the claims obvious, with motivation

Combination 1 (strongest — directed to claims 1–5, 10–11)

US 4,769,387A + FR 2 472 569A1, optionally + US 3,803,180A.

Motivation. Both references address the same technical problem — anti-inflammatory/antiallergic therapy — and both concern the dibenzofuran ring system. US 4,769,387A teaches that a dibenzofuran bearing hydroxy and alkyl/alkenyl substituents inhibits 5-lipoxygenase and treats asthma/arthritis/psoriasis; FR 2 472 569A1 supplies the known partially saturated (hexahydro) analogue of that exact ring system and teaches aromatic-ring alkyl/halo/alkoxy substitution. A skilled artisan seeking a new 5-lipoxygenase inhibitor would select the dibenzofuran scaffold already shown to inhibit the enzyme and would be led by FR 2 472 569A1 to its known hexahydro form, then place the known alkyl/alkenyl and hydroxy substituents at the positions the references teach. Under KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), this is a textbook "combination of familiar elements according to known methods" yielding no more than predictable results; it is at most an "obvious to try" optimization over a finite, identified set of ring-saturation and substituent options.

Reasonable expectation of success. The art reports 5-lipoxygenase inhibition in the structurally adjacent dibenzofuran (US 4,769,387A) and dihydrobenzofuran/coumaran (US 4,857,516A) series; a skilled artisan would reasonably expect the hexahydrodibenzofuran analogue to retain, or predictably modulate, that activity.

Combination 2 (directed to claims 1 and 2; the ketone/ol claims)

EP 0 067 769A1 + US 4,769,387A (optionally + FR 2 472 569A1).

Motivation. EP 0 067 769A1 teaches 1,2,3,4,4a,9b-hexahydro-4-dibenzofuranones/-ols as bronchodilator/antibronchoconstrictor agents — i.e., respiratory therapy, the very indication the claimed compounds target. US 4,769,387A teaches that the dibenzofuran ring system inhibits 5-lipoxygenase. Combining the known hexahydrodibenzofuran-4-one/ol core with the known lipoxygenase-inhibiting dibenzofuran pharmacophore would be an obvious optimization, especially because the 5-lipoxygenase/leukotriene pathway is the established biochemical cause of bronchoconstriction. This combination addresses the keto (X+Y = keto) and hydroxy (X or Y = OH) embodiments of claims 1–2 and the 3-one and 3-ol species of claim 5.

Combination 3 (directed to claims 1–5; addresses the two-ring substructure argument)

US 4,857,516A (and/or its sibling EP 0 273 647A1) + FR 2 472 569A1 (or US 3,317,527A / US 3,496,181A).

Motivation. Takeda teaches that 5-hydroxy-2,3-dihydrobenzofurans (coumarans) inhibit 5-lipoxygenase and treat leukotriene-mediated disease; FR 2 472 569A1 (or the Upjohn patents the specification itself uses to make the trans ring system) teaches how to fuse a cyclohexane ring onto the dihydrobenzofuran to give the hexahydrodibenzofuran. Adding a fused ring to a known active bicyclic pharmacophore, using known ring-annulation chemistry (Birch/Powell, Takahashi, Greenlee), is a routine structural variation with a predictable expectation of retaining activity. This combination is particularly damaging to claim 2 (trans-fused) because the Upjohn/Skaletzky art is the admitted route to that stereochemistry.

Combination 4 (directed to the method claims 6–11)

Any of Combinations 1–3 + US 4,769,387A (utility) [+ EP 0 067 769A1 (respiratory utility)] + US 3,803,180A (anti-inflammatory utility).

Motivation. Once the compounds are obvious, the method claims fall with them. The asserted utilities — inhibiting leukotriene biosynthesis and treating pulmonary/inflammatory/cardiovascular/skin conditions — are precisely the utilities the prior art attributes to the same class of compounds (US 4,769,387A: asthma, allergy, arthritis, psoriasis, inflammation; US 4,857,516A: antiallergic, cardiovascular; EP 0 067 769A1: bronchodilation). Where a compound is obvious and its utility is known or evident, the corresponding method-of-use claim is obvious. The specification itself concedes that "the hexahydrodibenzofuran structural framework has been shown to have anti-inflammatory and analgesic activity."

6. Rebuttal considerations (patentee's likely arguments)

• "Unexpected activity/selectivity of the specific 6- vs. 7-substituted species." A patentee could invoke secondary considerations, but the specification reports only in vitro PMN/LTB₄ data with no side-by-side comparison against the closest prior art (US 4,769,387A or US 4,857,516A). Absent a demonstrated unexpected result relative to the art, this argument is weak; potency differences among C₁–C₆ alkyl/alkenyl homologues are ordinarily predictable, not unexpected.
• Stereochemistry (4aS/9bS vs. 4aR*/9bS*, 3R* vs. 3S*).** The claims recite relative/racemic stereochemistry, and the specification's own Schemes III–IV obtain the epimers by routine reagent choice (triethylsilane vs. NaBH₄; hydrogenation). Stereochemical outcome from a chosen reducing agent is a predictable, routine design parameter and does not rescue the claims.
• Structural novelty of the exact tricycle. The specific hexahydrodibenzofuran-3-one/hydroxylated tricycle is not squarely named in any single reference; but under § 103, novelty of the combination is not required — obviousness of the combination of known elements is sufficient. See KSR; and In re Papesch, 315 F.2d 381 (CCPA 1963) (a compound is obvious if its properties would be obvious from the prior art).

I found no teaching-away in the record (e.g., no reference disparaging ring saturation or alkyl/alkenyl substitution on the dibenzofuran nucleus). If anything, the art points toward these modifications.

7. Conclusion and graded assessment

Overall: Claims 1–5 and 6–11 of US 4,978,679 would have been prima facie obvious under § 103 over US 4,769,387A in view of FR 2 472 569A1 (and/or US 4,857,516A and EP 0 067 769A1). The invention is best characterized as a predictable optimization of a known 5-lipoxygenase-inhibiting dibenzofuran/coumaran pharmacophore onto a known hexahydrodibenzofuran scaffold, using known chemistry. Absent comparative data showing unexpected results over the cited art, the claims do not appear to be salvaged by secondary considerations.

Caveats. (1) Actual anticipation/obviousness turns on the full text of each reference, and I did not retrieve the complete text of US 3,317,527A, US 3,496,181A, or EP 0 067 769A1; my characterization of EP 0 067 769A1 and the two Upjohn patents rests on their titles of record and the applicant's own description. (2) The "Similar Documents" on the page (e.g., US 4,966,907A and US 4,975,457A, both Merck, on 5-hydroxy-2,3-dihydrobenzofuran leukotriene-biosynthesis inhibitors) are highly probative of the state of the art but are not formal citations of record in this patent, and as near-contemporaneous sister filings they may or may not qualify as prior art depending on their dates; I therefore did not rely on them as the primary § 103 basis.