US Patent 5,585,397: Scope, Claim Coverage, and US Landscape
US Patent 5,585,397 claims a broad chemical genus centered on a specific stereodefined “tetrahydrofuryl oxycarbonyl-amino butyl” scaffold linked to an aromatic sulfonamide or sulfonylamide pattern, plus a set of explicit exemplified compounds, and formulation protection for antiviral use.
What the patent claims at a glance
Core claim structure (independent claim 1):
- A compound of formula XXII with variable substituents across three defined fragments:
1) A = 3-tetrahydrofuryl-O-C(O)- (fixed)
2) D’ = C1-C4 alkyl, optionally substituted by selected groups including C3-C6 cycloalkyl, OR2, R3, O-Ar, and aryl (Ar)
3) E = aryl (C6-C10), optionally substituted with an enumerated set of functional groups (halo, CF3, NO2, CN, OR2, etc.)
- Additional stereochemical constraints appear in the exemplified members: a (2 syn,3S) relationship and a tetrahydrofuran-3-yloxycarbonylamino stereochemical setting.
Dependent claims:
- Claim 2 lists a large set of specific compounds by name (compounds 35, 37, 48, 52, 86, 88, 91, 93, 94, 99, 100, 112, 116, 125, 138, 140, 148, 158, 159, 160, 165, 167, 168, 169, 170, 171, 173, 175, 182, 183, etc.).
- Claim 3 selects a subset of those.
- Claim 4 fixes a specific instantiation: A = (S)-3-tetrahydrofuryl-O-C(O)-, D’ = isobutyl, E = 4-aminophenyl.
- Claims 5–8 cover pharmaceutical compositions for viral infection and single-out at least one named compound for composition claims.
How broad is Claim 1’s chemical genus?
Fixed scaffold elements
Claim 1 fixes:
- A = 3-tetrahydrofuryl-O-C(O)-
This is a strong structural anchor. In practical freedom-to-operate (FTO) terms, it reduces design-around options because the “tetrahydrofuryl oxycarbonyl” motif and connectivity are mandatory.
Adjustable elements inside the genus
Claim 1 permits variability primarily in:
- D’ fragment (alkyl C1-C4 with optional substitution options)
- E aryl fragment (C6-C10 aryl with broad substitution list)
- R2 and R3 substituent classes
- Z substituent members inside R3 (limited to cycloalkyl, alkenyl, aryl types)
- Ar ring identity and substitution list
Enumerated substitution space on E (aryl)
E can be an aryl ring (C6-C10) optionally substituted by:
- oxo
- OR2
- R2
- N(R2)(R2) (shown in claim as N(R2) (R2) formatting variants)
- R2-OH
- CN
- CO2R2
- C(O)N(R2)(R2)
- S(O)2N(R2)(R2)
- N(R2)C(O)R2
- C(O)R2
- S(O)nR2 where n is 1 or 2
- OCF3
- S(O)nAr
- methylenedioxy
- N(R2)S(O)2(R2)
- halo
- CF3
- NO2
- Ar
- O-Ar
This is a large set of medicinal-chemistry-relevant groups, and it is not limited to ring substitution by small halogens only. It includes sulfonamide-adjacent and carbonyl-containing functionalities and sulfone-like patterns via S(O)n and S(O)2.
Substitution space for Ar (carbocyclic ring)
Ar is a 3-6 membered carbocycle, saturated/unsaturated, with optional substitution from the same broad group list (oxo, OR2, R2, amide-like, halo, CF3, etc.).
What Claim 1 practically covers
- A “one-size-fits-many” structure-based protection that is constrained at the functional group “ends” by:
- the fixed A motif
- the fixed presence of the stereodefined butyl-amide/sulfonamide region implied by formula XXII and the exemplified compounds
The breadth is therefore “large in peripheral substituents, narrow at the core scaffold.”
What do Claims 2 and 3 add over Claim 1?
Claim 2: enumerated examples that lock in specific members
Claim 2 recites a long list of specific compounds, each with systematic names and “compound numbers.” In US practice, this:
- strengthens evidentiary support that the genus is actually enabled and not a paper concept
- supports narrower claim interpretations if prosecution or litigation relies on those named species as exemplifying the broader formula
Key exemplified families in Claim 2 include:
- Aromatic substitution variants (fluoro, chloro, amino, hydroxy, nitro, methoxy)
- Ar position variants (para vs meta)
- Sulfonamide type variability (benzenesulfonamide, sulfamoyl-linked acetamide variants, benzene-1,3-disulfonic acid 1-amide derivative)
- Sidechain nitrogen substituent changes (isobutyl vs cyclopentylmethyl vs cyclohexylmethyl)
- Stereochemical variants in the tetrahydrofuran-3-yloxycarbonylamino region appear as (S) vs (R) in the names
Claim 3: reduces to a smaller selection
Claim 3 narrows to a set including:
- compound 48
- compound 100
- compound 116
- compound 140
- compound 148
- compound 158
- compound 160
- compound 168
- compound 171
- compound 173
- compound 175
- plus compound 182 and compound 183
This selection shows which members the applicant treated as important. For litigation, those species can become reference points for claim construction of the genus terms.
What is Claim 4’s narrow target?
Claim 4 sets:
- A = (s)-3-tetrahydrofuryl-O-C(O)-
- D’ = isobutyl
- E = 4-aminophenyl
This is a significant reduction from Claim 1 because it fixes:
- the stereochemical assignment on A (explicit s)
- the D’ substituent identity (isobutyl)
- the E ring identity (4-aminophenyl)
Even if a competitor stays inside Claim 1’s permissive “E optional substitutions” list, Claim 4 acts as an additional claim layer for the specific 4-aminophenyl / isobutyl combination.
How do the composition claims expand patent value?
Viral infection pharmaceutical compositions (Claim 5)
Claim 5:
- covers a pharmaceutical composition effective against viral infection
- containing a “pharmaceutically effective amount” of a compound according to Claim 1 plus a pharmaceutically acceptable carrier/adjuvant/vehicle
Claim 5 also lists many specific compounds as permitted actives, mirroring the enumerated species from Claim 2.
Dependent composition claims (Claims 7 and 8)
- Claim 7 lists a smaller subset of compounds as actives for the viral infection composition.
- Claim 8 isolates a single compound:
- 4-Amino-N-((2 syn,3S)-2-Hydroxy-4-phenyl-3-((S)-tetrahydrofuran-3-yloxycarbonylamino)-butyl)-N-isobutyl-benzenesulfonamide (compound 168)
This layered drafting is typical when the applicant wants:
- broad composition protection for the genus (Claim 5)
- narrower composition fallbacks for selected best-in-class members (Claim 7)
- a single-compound “anchor” claim that can survive if other actives are found non-infringing.
Which structural “design-around” levers are weak vs strong?
Strong levers (harder to design around)
- Removing or altering the A motif is difficult because Claim 1 requires A = 3-tetrahydrofuryl-O-C(O)-.
- Changing the stereochemical pattern might still be difficult because Claim 1 is expressed by formula XXII (with implicit stereochemical definitions), while multiple dependent claims and named species lock in specific stereochemistry.
Weaker levers (more feasible to design around)
If a third party stays away from the fixed A motif, they can potentially avoid Claim 1 entirely. But if they keep A, the next freedom is in substituents:
- replacing the E aryl with a non-C6-C10 aryl element
- using substitution patterns not captured by the enumerated E substituents (e.g., functional groups not in the list)
- changing D’ from C1-C4 alkyl
However, the claim uses broad categories and includes many substituents via OR2, R2, CN, CO2R2, halo, CF3, NO2, and S(O)n patterns. That makes “substitution-based” design-around less reliable if the competitor’s chemistry maps onto those groups.
US patent landscape implications (what this patent blocks in-market)
What this patent likely targets commercially
While the claim text is the primary legal artifact, the structure suggests a specific class of antiviral agents with:
- a chiral, substituted butyl amide region
- a sulfonamide-like functional arrangement
- an aromatic ring with variable substitution
Claim 5–8 explicitly tie the compositions to viral infection, giving the patent a route to enforcement against formulated products that use covered actives.
Expected competition pattern
In the US landscape, patents like this typically face challenge and narrowing via:
- generic substitution within the genus for E/D’/sidechain nitrogen
- stereochemistry swaps between (S)/(R) placements
- prodrug or salt strategies (though Claim 1 covers compounds; Claim 5 covers compositions)
Because Claim 2/3 contain many explicit members, enforcement can proceed not only on the genus interpretation but on the named exemplars.
Where the claims provide litigation-ready leverage
For an accused product or candidate:
- if its active maps to one of the named species in Claim 2/3, a defendant can face “direct” infringement arguments with fewer interpretive steps.
- if it maps to a genus variant, the breadth of permissible groups becomes the central claim-construction issue.
Claim coverage map (practical reading for infringement assessment)
| Claim element |
What must be present |
How infringement can occur |
| A |
fixed 3-tetrahydrofuryl-O-C(O)- |
If active includes this oxycarbonylated THF moiety, Claim 1 scope begins |
| D’ |
C1-C4 alkyl (optionally substituted) |
If D’ is isobutyl, tert-butyl, propyl, methyl, etc., likely captured depending on optional substituent allowance |
| E |
C6-C10 aryl optional substituents |
If E is phenyl/benzene-type with substituents from the listed set, Claim 1 scope likely includes it |
| R2 / R3 / Z |
defined by broad substituent classes |
Many “common medicinal chemistry” groups are explicitly allowed |
| Dependent compositions |
pharmaceutically acceptable carrier; active is a covered compound |
Products using covered actives in antiviral formulations trigger Claims 5–8 |
This claim architecture makes the patent a blend of:
- genus protection for chemical space around the fixed core
- species protection via enumerated compound lists
- product protection via formulation claims
Key Takeaways
- Claim 1 is a broad genus built on a fixed 3-tetrahydrofuryl-O-C(O)- “A” motif, with wide permissible variability on E aryl substitution, and defined substitution classes for D’, R2, R3, Z, and Ar.
- Claims 2 and 3 materially strengthen enforcement by listing many specific stereodefined compounds by name, including multiple fluorinated and chlorinated aryl variants and different N-substituent patterns (isobutyl, cyclopentylmethyl, cyclohexylmethyl).
- Claim 4 is a narrow fallback for the isobutyl / 4-aminophenyl / (S)-A configuration.
- Claims 5–8 create formulation hooks for “viral infection” and single out compound 168 as a dedicated composition claim, supporting continued patent leverage even if genus interpretation narrows.
FAQs
1) Does US 5,585,397 claim a single molecule or a chemical class?
It claims a chemical class (genus) in Claim 1 and then provides numerous specific named compounds in Claims 2 and 3.
2) What is the strongest structural anchor for infringement analysis?
The fixed fragment A = 3-tetrahydrofuryl-O-C(O)- is the most constrained element in Claim 1.
3) How do the named compounds in Claim 2 change the risk profile?
They create a more direct infringement path if an accused active matches any named compound in the lists.
4) Do the claims cover formulations or only compounds?
They cover pharmaceutical compositions for viral infection (Claims 5–8), not only the chemical entities.
5) What is Claim 4 designed to capture?
A specific configuration with D’ = isobutyl and E = 4-aminophenyl (plus fixed A stereochemistry).
References
[1] United States Patent No. 5,585,397. “A compound of formula XXII” and pharmaceutical compositions effective against viral infection. United States Patent and Trademark Office.
