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Patent landscape, scope, and claims: |
Executive summary
US Patent 4,886,812 claims a chemical genus of “tetrahydro-benzthiazoles” defined by substituent variables R1 to R4, plus tighter subgenera (positional isomers; specific R1/R2/R3/R4 combinations that yield particular amine-bearing derivatives) and at least one specific compound (2-amino-6-dimethylamino-4,5,6,7-tetrahydro-benzthiazole, and an N-propylamino analog). The estate, based strictly on claim text provided, is structured to cover: (1) a broad structural class, (2) regiospecific embodiments (5- vs 6-position placement of a key ring substituent), (3) amine patterning that creates several tertiary amine subtypes, and (4) method-like therapeutic use via compositions for cardiovascular and central nervous system indications. The dominant infringement risk for competitors is structural: any US-made or US-sold tetrahydro-benzthiazole meeting the R-group constraints (and salts) falls within claim 1 or claim 3/5/6/7 pathways, with composition claim 8 expanding coverage to formulated products using claim-3 compounds.
US Patent 4,886,812 what is the claim scope for tetrahydro-benzthiazoles
Core coverage
From the claim set provided, the patent uses a two-layer claim strategy: a broad genus (independent claim 1), a narrower genus (independent claim 3), then specific species (claims 6 and 7), and finally a formulation claim (claim 8).
Claim 1 genus: tetrahydro-benzthiazoles with R1-R4 substituent constraints
Claim 1 locks the scaffold and defines variable substituents
- It covers “tetrahydro-benzthiazole of the formula (I)” where:
- R1 is selected from:
- H
- alkyl (C1–C6)
- alkenyl or alkynyl (C3–C6)
- alkanoyl (C1–C6)
- phenyl-alkyl or phenyl-alkanoyl with phenyl-alkyl C1–C3 (and phenyl-alkanoyl with alkyl part C1–C3), where the phenyl ring may be substituted with 1 or 2 halogens.
- R2 is H or alkyl (C1–C4)
- R3 is selected from:
- H
- alkyl (C1–C7)
- cycloalkyl (C3–C7)
- alkenyl or alkynyl (C3–C6)
- alkanoyl (C1–C7)
- phenyl-alkyl or phenyl-alkanoyl with C1–C3 in the alkyl part
- where the phenyl nucleus is substituted by F, Cl, or Br
- R4 is selected from:
- H
- alkyl (C1–C4)
- alkenyl or alkynyl (C3–C6)
- or R3 and R4 together with the nitrogen form a cyclic amine: piperidino, hexamethyleneimino, or morpholino
- plus acid addition salts of the compounds.
Practical read-through for freedom-to-operate
Claim 1 is a “meet-the-definition” claim. If a candidate compound’s structure matches the tetrahydro-benzthiazole scaffold and its R-group pattern fits any permitted combinations, it lands in claim 1, including salts.
Key scope features:
- Broad tolerance for hydrophobic substituents (alkyl, cycloalkyl, alkenyl, alkynyl, and acyl groups).
- Broad tolerance for substituted phenyl moieties, including halogen substitution limits (claim 1 specifies 1 or 2 halogens on the R1 phenyl; and F/Cl/Br on the R3 phenyl).
- A structural “escape hatch” is limited because R4 is either an allowed substituent or the pair R3/R4 can cyclize into N-containing rings.
Claim 2 regiospecific subgenus: positional placement in the ring
Claim 2 specifies that the substituted group indicated as “(##STR17##)” is in the 5 or 6 position.
This is a typical regiospecific narrowing: even if a competitor is inside claim 1’s genus, claim 2 gives a second claim pathway for infringement when the candidate’s substitution pattern matches the 5- or 6-position embodiment.
Claim 3 narrower genus: tetrahydro-benzthiazoles with more explicit substituent sets
Claim 3 defines a second set “tetrahydro-benzthiazole of formula (Ia)” with tighter lists:
- R1: H, alkyl C1–C3, allyl, benzyl, 2-chloro-benzyl, 4-chloro-benzyl, 3,4-dichloro-benzyl, or phenylethyl.
- R2: H, methyl, or ethyl.
- R3: H, alkyl C1–C6, allyl, propargyl, benzyl, chlorobenzyl, phenylethyl, cyclopentyl, cyclohexyl.
- R4: H, alkyl C1–C3, or allyl.
- Or R3 and R4 together with the nitrogen atom form piperidino, hexamethyleneimino, or morpholino.
- Plus pharmaceutically acceptable acid addition salts.
Where claim 3 matters
Claim 3 is a curated subset of claim 1’s broad genus, with fewer allowed substituents but a more explicit and likely commercially relevant list (benzyl derivatives, chloro-benzyl, dichloro-benzyl, phenylethyl, and specific amine patterns via R3/R4 ring formation).
Claim 4 regiospecific: the “(##STR19##)” group in the 6-position
Claim 4 further narrows claim 3 compounds where the indicated ring substituent is in the 6-position.
Claim 5 additional subgenus: defined amine patterning
Claim 5 narrows claim 3 by imposing two combined constraints:
- R1 and R2 together with the nitrogen form an amino or allylamino group.
- R3 and R4 together with the nitrogen form one of:
- dimethylamino
- diethylamino
- N-allyl-N-(4-chloro-benzyl)-amino
- n-propylamino
This claim is a high-value bridge to the species claims because it ties R-group structure to specific dialkyl/alkenyl/benzyl amine motifs.
Claims 6 and 7: specific species
- Claim 6: 2-amino-6-dimethylamino-4,5,6,7-tetrahydro-benzthiazole, or an acid addition salt.
- Claim 7: 2-amino-6-n-propylamino-4,5,6,7-tetrahydro-benzthiazole, or an acid addition salt.
These are straightforward “species claims.” Any competitor selling the exact compound (including salt forms covered as “acid addition salts”) has direct exposure.
How do the dependent claims tighten the tetrahydro-benzthiazole structure coverage
Position control
- Claim 2: (##STR17##) at 5 or 6.
- Claim 4: (##STR19##) at 6.
Functional amine pattern control
- Claim 5 defines nitrogen substitution outcomes: amino/allylamino at one nitrogen relationship, and a fixed list of tertiary/bulk substituents at the other.
N-ring closure option
- Claims 1 and 3 include “R3 and R4 together with the nitrogen atom between them” forming piperidino, hexamethyleneimino, or morpholino. This means competitors cannot avoid claim coverage simply by cyclizing the amines unless the resulting scaffold breaks the specified ring types or fails the tetrahydro-benzthiazole core structure and formula constraints.
What salts are covered in US Patent 4,886,812 and how does salt inclusion affect infringement
Across claims 1, 3, 5, 6, and 7, the patent expressly includes:
- “an acid addition salt thereof”
- “pharmaceutically acceptable acid addition salt”
In infringement and design-around terms
- Salt selection is not a robust design-around if the salt remains an “acid addition salt” of a compound within the formula definitions.
- If a competitor’s active is a base that the prior art lists as part of the genus, converting it to a non-acid addition salt (for example, a non-qualifying salt form not described as “acid addition salt”) may be outside literal “acid addition salt” language, but structural definition of the free base remains the main risk vector.
What formulations and therapeutic claims are protected by US 4,886,812
Composition claim 8
Claim 8 covers:
- A pharmaceutical composition suitable for treating a disorder selected from:
- high blood pressure
- tachycardia
- Parkinson’s disease
- Parkinsonism
- schizophrenia
- comprising:
- a therapeutically effective amount of a compound according to claim 3
- plus a pharmaceutically acceptable carrier diluent.
Implications
- Claim 8 is not a method-of-treatment claim as a standalone process; it is a composition claim with therapeutic use categories embedded in the claim.
- In practice, for infringement analysis, the composition must contain a claim-3 compound. If a product’s active ingredient falls under claim 3, then formulation into a pharmaceutically acceptable carrier brings claim 8 into play for those specified disease categories.
What specific compounds are explicitly claimed in US Patent 4,886,812
Species explicitly listed
- 2-Amino-6-dimethylamino-4,5,6,7-tetrahydro-benzthiazole (and acid addition salts) (Claim 6).
- 2-Amino-6-n-propylamino-4,5,6,7-tetrahydro-benzthiazole (and acid addition salts) (Claim 7).
Subgenus that captures multiple amine patterns
- Claim 5 captures multiple tertiary amine substitution states:
- dimethylamino
- diethylamino
- N-allyl-N-(4-chloro-benzyl)-amino
- n-propylamino
as long as the corresponding R relationships fit the claim 3 framework.
How broad is US 4,886,812 compared to typical tetrahydro-benzthiazole patent claim sets
Breadth drivers
- Claim 1 permits multiple substitution chemistries: alkyl, alkenyl, alkynyl, acyl, and substituted phenyl for both R1 and R3, plus cyclic N-containing ring formation.
- Claim 3 narrows the substituent lists but remains broad enough to include benzyl and chlorobenzyl series and cycloalkyls.
Key narrowing levers
- Oxygen-free scaffold specificity (“tetrahydro-benzthiazole” core).
- Fixed valence relationships implied by the R1/R2/R3/R4 formula.
- Limited halogen substitution rules (F/Cl/Br on phenyl at R3; 1–2 halogens on phenyl at R1).
Where would generic or competitor entry face the highest IP barriers under this patent
Highest risk zones
- Competitors launching products with actives that are either:
- identical to claims 6 or 7 species, or
- inside claim 5’s defined amine pattern list, or
- inside claim 3’s curated substituent sets.
- Products formulated for any of the therapeutic disorder categories stated in claim 8 using a claim-3 compound.
Lower risk zones
- Compounds that maintain the tetrahydro-benzthiazole scaffold but use substituents outside the enumerated ranges for R1/R2/R3/R4 in claim 3.
- Compounds outside claim 1’s full genus constraints.
- Salt forms that are not “acid addition salts” of the covered free bases (but structural match to the free base remains decisive).
Is there enough information here to list the full patent landscape (other patents, Orange Book listings, litigation, Paragraph IV, expiries) for US 4,886,812
No. The claim text provided does not include the patent’s bibliographic record (assignee, filing date, publication data), related family members, prosecution history, or any FDA/Orange Book identifiers. Without those, a complete and accurate US landscape mapping cannot be produced from the information provided.
Key Takeaways
- US 4,886,812 is structured around a tetrahydro-benzthiazole chemical genus (claim 1) and a tighter genus (claim 3), with regiospecific embodiments (claims 2 and 4), defined nitrogen substitution subgenus (claim 5), and two explicit species (claims 6 and 7).
- The strongest actionable infringement exposure is structural: any compound that matches the R-group constraints for claim 1 or claim 3, including acid addition salts, is at risk.
- Claim 8 creates additional exposure for formulated products using a claim-3 compound for specified cardiovascular and CNS indications.
- Salt form alone is unlikely to be a meaningful design-around because the patent expressly covers acid addition salts of covered bases.
FAQs
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Does US 4,886,812 cover both free bases and acid addition salts?
Yes, the claims expressly include acid addition salts and pharmaceutically acceptable acid addition salts.
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Which claim best captures exact drug candidates for market-entry risk: claim 1 or claim 3?
Claim 3 is the best direct bridge to commercially relevant actives because claim 8 ties composition coverage to “a compound according to claim 3,” and claims 6 and 7 are specific to discrete structures.
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How do claims 2 and 4 affect design-around efforts?
They add regiospecific limitations on the position of a ring substituent, enabling infringement on specific positional isomers even where broad genus boundaries might be contested.
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What therapeutic areas are covered by the composition claim?
High blood pressure, tachycardia, Parkinson’s disease, Parkinsonism, and schizophrenia.
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Can competitors avoid the patent by swapping substituents on the benzene ring?
Not if the substitution pattern still falls within the claim-defined halogen constraints for the phenyl rings at the specified R positions (claim 1: F/Cl/Br on the R3 phenyl; claim 1: 1 or 2 halogens on the R1 phenyl).
References (APA)
- US Patent 4,886,812.
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