United States Patent 4,418,068: Scope of Claims and U.S. Patent Landscape

US Drug Patent 4,418,068 claims a broad genus of substituted benzo[b]thiophene derivatives, the physiologically acceptable esters/ethers and acid addition salts of those compounds, and downstream pharmaceutical compositions and endocrine-use methods. The claims are structured around (i) a compound Markush formula with substituent variables R, R1, R2, R3, (ii) a set of dependent claim “anchor” embodiments, and (iii) use claims covering antiestrogenic and antiandrogenic treatment of endocrine-dependent conditions.

What is the claim scope at the compound level?

Independent claim coverage

Claim 1 is a Markush-style genus claim:

A compound of the formula (STR5)
or a physiologically acceptable ester or ether
or a physiologically acceptable acid addition salt

Claim 17-19 add additional claim layers for forms:

Claim 17: free base
Claim 18: physiologically acceptable acid addition salt
Claim 19: hydrochloride

Interpretation for scope: Claim 1 is not limited to one structure; it covers the entire genus defined by formula (STR5), plus typical prodrug/derivative salt/ester/ether variants and specific salt forms via dependent claims.

What is the substituent definition (R, R1, R2, R3) that drives breadth?

Claim 2 defines the core substituent space. It covers compounds where:

R and R1 are independently:
- hydrogen
- --COR2
- R3
R2 options:
- hydrogen
- C1-C14 alkyl
- C1-C3 chloroalkyl
- C1-C3 fluoroalkyl
- C5-C7 cycloalkyl
- C1-C4 alkoxy
- phenyl
- phenyl mono- or disubstituted with C1-C4 alkyl, C1-C4 alkoxy, hydroxy, nitro, chloro, fluoro or tri(chloro or fluoro)methyl
R3 options:
- C1-C4 alkyl
- C5-C7 cycloalkyl
- benzyl
plus physiologically acceptable acid addition salt thereof

Key breadth levers in Claim 2

R/R1 independence: the claim allows asymmetry (R ≠ R1).
--COR2: permits acyl-derived substituents with a wide R2 distribution, including long-chain alkyl (up to C14) and multiple aromatic/halogenated aryl patterns.
R3: includes alkyl, cycloalkyl, and benzyl.
The claim spans free base and salts in later dependent claims.

What specific “foreground” embodiments are explicitly called out?

The patent includes multiple dependent claims identifying specific named compounds within the Markush boundaries.

Explicitly named core compound

Claim 3: 6-hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinoethoxy)benzoyl]benzo[b]thiophene (or physiologically acceptable acid addition salt)

Specific acyl/ester variants at positions 6 and 2-(4-hydroxyphenyl)

Claim 20: 6-acetoxy-2-(4-acetoxyphenyl)-3-[4-(2-piperidinoethoxy)benzoyl]benzo[b]thiophene
Claim 21: 6-benzoyloxy-2-(4-benzoyloxyphenyl)-3-[4-(2-piperidinoethoxy)benzoyl]benzo[b]thiophene
Claim 22: 6-ethoxycarbonyloxy-2-(4-ethoxycarbonyloxyphenyl)-3-[4-(2-piperidinoethoxy)benzoyl]benzo[b]thiophene
Claim 23: 6-methoxy-2-(4-methoxyphenyl)-3-[4-(2-piperidinoethoxy)benzoyl]benzo[b]thiophene

Named compound at the “ester/ether” substitution family

Claim 37: 6-methoxy-2-(4-methoxyphenyl)-3-[4-(2-piperidinoethoxy)benzoyl]benzo[b]thiophene (composition layer)

These named embodiments serve as high-value claim coverage targets because they are both: 1) explicitly claim recited as compounds, and
2) later mirrored in composition and method claims.

How do dependent claims narrow scope around R and R1 patterns?

The claim set uses multiple dependency tracks to narrow the Markush space while preserving alternative pathways to coverage.

Stereotyped narrowing triggers

Claim 4: R and R1 are the same, and are other than hydrogen
Claim 5: one of R and R1 is hydrogen
Claim 6: one or both of R and R1 is --COR2
Claim 7: one or both of R and R1 is R3

Further narrowing for the substituent selection

Claim 8: (within claims 2/4/6) R2 is C1-C14 alkyl
Claim 9: R2 is C1-C3 chloroalkyl or C1-C3 fluoroalkyl
Claim 10: R2 is C5-C7 cycloalkyl
Claim 11: R2 is C1-C4 alkoxy
Claim 12: R2 is phenyl
Claim 13: R2 is substituted phenyl (explicit substituent list)
Claim 14-16: R3 is constrained to C1-C4 alkyl, C5-C7 cycloalkyl, or benzyl

Form claims

Claim 17-19: free base, acid addition salts, and specifically hydrochloride

Practical scope consequence: Even when narrowing, the patent maintains multiple parallel claim “routes” into overlapping chemical subspaces, so design-arounds that avoid one substituent category can still fall within alternative categories unless they exit the entire genus framework.

What is the scope for pharmaceutical compositions?

Claim 24 is an independent composition claim:

An antiestrogenic and antiandrogenic pharmaceutical composition
comprising:
- a pharmaceutically acceptable diluent, and
- an effective amount of the compound of the formula (STR7), including:
- physiologically acceptable esters/ethers
- physiologically acceptable acid addition salts

Dependent composition claims mirror the compound Markush

Claims 25-27: composition coverage with the same R/R1/R2/R3 definition; includes named compound and hydrochloride:
- Claim 26: hydroxy-hydroxy core compound
- Claim 27: that compound as hydrochloride
Claims 28-35: composition narrowing where R and R1 match and are other than hydrogen, including:
- --COR2 routes
- R2 alkyl (C1-C14), chloroalkyl/fluoroalkyl routes implicitly via the Markush chain
- R2 phenyl and substituted phenyl routes
- named benzoyloxy/acetoxy/ethoxycarbonyloxy variants

Additional composition anchors

Claim 37: methoxy-methoxy named compound
Claim 38: one of R and R1 is hydrogen
Claim 31/33/35: specific acyl/ester named embodiments

Scope consequence: The composition claims are tethered directly to the compound genus and its specific named exemplars, with no added functional limitations besides “antiestrogenic and antiandrogenic” labeling and “effective amount.”

What is the scope for methods of treatment?

Independent method claim

Claim 39:

“A method of alleviating a pathological condition of an endocrine target organ”
where the condition is dependent or partially dependent on estrogen or androgen
includes:
- administering an effective dose of the compound (formula STR9)
- including physiologically acceptable ester/ether or acid addition salt.

Method dependency bifurcates by hormone driver

Claims 40-45: estrogen-dependent cases
- Claim 42: target organ is breast, condition mammary cancer
- Claim 44: target organ is breast, condition fibrocystic disease
- Claims 41/43/45: dosing windows (below)
Claims 46-51: androgen-dependent cases
- Claim 48: target organ prostate, condition prostatic cancer
- Claim 50: target organ prostate, condition benign prostatic hypertrophy
- Claims 47/49/51: dosing windows (below)

Dosing ranges are explicitly claimed

Claim 41: 0.05 mg/kg/day to 50 mg/kg/day (estrogen-dependent)
Claim 43: 0.1 mg/kg/day to 10 mg/kg/day (mammary cancer)
Claim 45: 0.1 mg/kg/day to 10 mg/kg/day (fibrocystic disease)
Claim 47: 0.05 mg/kg/day to 50 mg/kg/day (androgen-dependent)
Claim 49: 0.1 mg/kg/day to 10 mg/kg/day (prostatic cancer)
Claim 51: 0.1 mg/kg/day to 10 mg/kg/day (BPH)

Named compound method claims

Claim 53-54: hydroxy-hydroxy compound, including hydrochloride
Claims 57-59: acetoxy, benzoyloxy, ethoxycarbonyloxy named variants
Claims 60-61: R and R1 are R3, including methoxy-methoxy named compound
Claim 62: one of R and R1 is hydrogen

Scope consequence: The method claims are broad at the hormonal mechanism level (estrogen or androgen dependent) but narrow at dosing and organ/disease mapping through dependent claims.

Claim scope map: how the same chemical genus is leveraged across product forms and uses

Coverage matrix

Layer	Claim numbers	What it covers	Key limitations
Compound genus	1-2	Markush formula with esters/ethers and acid addition salts	variables R/R1/R2/R3 per Claim 2
Named exemplars	3, 20-23	specific benzo[b]thiophene derivatives	explicit chemical identities
Form-specific	17-19	free base, acid addition salt, hydrochloride	hydrochloride singled out
Composition	24-38	antiestrogenic/antiandrogenic formulations	must include pharmaceutically acceptable diluent and effective amount
Treatment method	39-62	alleviating endocrine-dependent conditions	organ/disease mapping and dosing windows in dependent claims

What is the practical “patent landscape” implication from this claim architecture?

The claim set is built to maximize entry points:

Chemical-genus coverage (Claim 1-2)
Substitution-category coverage (Claims 4-16 and 8-13, 14-16)
Specific compound embodiments (Claims 3, 20-23)
Pharmacological deployment (composition Claim 24 and method Claim 39)
Use in estrogen- and androgen-dependent conditions (Claims 40-51)
Explicit dosage windows (Claims 41-45, 47-51)

This matters because a competitor design-around must clear multiple gates simultaneously: 1) exit the structural genus formula space, and 2) avoid all recited substitution categories (R/R1/R2/R3 constraints), and 3) avoid the identified named exemplars if practicing the same compound family, and 4) if manufacturing, avoid composition forms that still satisfy “effective amount” of a claimed compound, and 5) if marketing/using, avoid the specific endocrine disease indications and dose ranges embedded in dependent method claims.

U.S. patent landscape: competitors, continuations, and related families

No external record details were provided here (e.g., application number, assignee, priority dates, prosecution history, citations, or related U.S. continuations/continuations-in-part). Without those identifiers, a complete, claim-by-claim landscape against:

other U.S. patents citing the same compound,
portfolio families covering salts/esters/ethers,
method-of-treatment continuations,
or overlapping benzo[b]thiophene endocrine-use patents, cannot be generated from the claim text alone.

Given the absence of bibliographic and litigation/maintenance data, the only defensible landscape characterization is structural: the patent is positioned as a broad genus plus formulation and endocrine-use claims. That implies overlap risk with later entrants only if they practice within the same benzo[b]thiophene substitution space and use the same estrogen/androgen-dependent indications at claimed dose bands.

Key Takeaways

Breadth is driven by Claim 2’s substituent Markush: independent R/R1 options (H, --COR2, R3) and wide R2 definitions (C1-C14 alkyl plus halogenated alkyl, cycloalkyl, alkoxy, phenyl and substituted phenyl; plus R3 alkyl/cycloalkyl/benzyl).
The patent anchors multiple named compounds (hydroxy-hydroxy core and acetoxy/benzoyloxy/ethoxycarbonyloxy/methoxy variants), which lock in coverage against specific implementation choices.
Claims extend beyond chemistry into:
- pharmaceutical composition claims (Claim 24 onward) and
- methods of treatment with endocrine organ/disease mapping and explicit dosing ranges (Claims 41-45 and 47-51).
A design-around requires exiting the chemical genus and all relevant dependent substitution/form/dose/indication pathways built across compound, composition, and method claims.

FAQs

1. Does the patent cover ester and ether derivatives of the core compound?

Yes. Claim 1 explicitly includes “a physiologically acceptable ester or ether” of the formula compound, and salts are covered as well.

2. Are salts limited to acid addition salts generally, or are specific salts claimed?

Both. Claim 1 covers physiologically acceptable acid addition salts, and dependent claims specifically include free base (Claim 17), acid addition salt (Claim 18), and hydrochloride (Claim 19), with corresponding composition and method references.

3. What diseases and endocrine organs are explicitly tied to dosing ranges?

Estrogen-dependent: breast mammary cancer (Claim 42, dose Claim 43) and fibrocystic disease (Claim 44, dose Claim 45).
Androgen-dependent: prostate prostatic cancer (Claim 48, dose Claim 49) and benign prostatic hypertrophy (Claim 50, dose Claim 51).

4. Is the method claim limited to one compound identity?

No. Method claims cover the broader formula genus in Claim 39-52 and then recite specific exemplars (Claims 53-61) through dependent claims.

5. What is the highest-level scope lever for chemical coverage?

Claim 2: it defines the substitution space for R, R1, R2, and R3 using broad categorical definitions, including long-chain alkyl and substituted phenyl patterns.

References

[1] U.S. Patent 4,418,068 (claims provided in the prompt text).

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Details for Patent: 4,418,068

Summary for Patent: 4,418,068