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Patent landscape, scope, and claims: |
United States Patent 9,126,931: Scope, Claims, and Patent Landscape for a Benzo[b]carbazole Nitrile Scaffold
US 9,126,931 claims a large family of benzo[b]carbazole-based compounds defined by Formula (I), with expansive Markush options on multiple substituent positions. Independent claim 1 is a broad genus claim that covers: (i) salts and solvates, (ii) a benzo[b]carbazole core containing a carbonitrile motif, and (iii) a wide combinatorial set of substituents at the core’s peripheral positions via variables R1 through R10 and A1 through A10.
The dependent claims narrow the genus in two ways: (1) by setting specific sub-classes for key variables (A5, R3, etc.), and (2) by listing specific exemplified compounds by name. The exemplified set is concentrated in the same structural theme: halogen or alkyl/alkynyl substitution patterns at the “9” position, piperazine/piperidine/morpholine-like solubilizing groups at the “8” position, and an “11-oxo” functionality consistent with the same lactam-like oxidation state.
What does claim 1 actually cover?
How is the protected structure defined in claim 1?
Claim 1 covers “a compound or salt or solvate thereof” represented by Formula (I), with the following hard constraints:
- Core atom assignments:
A1, A2, A3, A4, A7, A8, A9, A10 are each C.
- Heteroatom at A5: A5 is NR5, O, or S.
- Substituent knobs at R1 and R10: each independently is one of:
1) H
2) CN
3) halogen
4) heterocycloalkyl group (4- to 10-membered) that may itself be substituted by additional heterocycloalkyl groups (4- to 10-membered).
- Substituent knob at R2: H, C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, CN, halogen, or amino-bearing alkyl (including “(C1-8 alkyl)-amino” optionally sulfonylated), or nitro. Also includes m2: 0 to 2 (variable expansion count).
- Substituent knob at R3: a long Markush set including H, C1-8 alkyl, substituted alkyl, halogen, aryl, CN, multiple carbonyl-containing groups, amino-carbonyl variants, nitro, hydroxy, multiple alkoxy and aryloxy/aminocarbonyloxy forms, heterocycloalkyloxy and heteroaryloxy groups, and sulfonyl oxy variants.
Includes m3a, m3b, m3c, m3d, m3e: 0 to 2.
- Substituent knob at R4: H, C1-8 alkyl (optionally halogen-substituted), alkenyl/alkynyl, cycloalkyl, CN, aminocarbonyl, hydroxycarbonyl, halogen, amino-carbonyl (m4a: 1 to 2), hydroxy, and alkoxy (optionally hydroxy-substituted).
- Substituent knob at R5: H, C1-8 alkyl (optionally substituted at R5A), alkenyl/alkynyl/cycloalkyl, or alkylsulfonyl.
Includes m5: 0 to 2 for R5A expansion count.
- Linkers/side chain at R6 and R6′:
- R6 and R6′ are independently alkyl/alkenyl/alkynyl, or taken together to form cycloalkyl or substituted heterocycloalkyl (4- to 10-membered) bearing sulfonyl substitution.
- Substituent knobs at R7, R8, R9, R10:
- R7: H, halogen, substituted alkoxy, alkylsulfonyl, nitro, hydroxyl, and alkoxy substituents with amino substitution (m7a: 0 to 2).
- R8: a very large Markush set ranging from H to substituted alkyl, alkenyl, multiple oxy and sulfonyloxy variants, heteroaryl/heterocycloalkyl versions, aminosulfonyl/aminocarbonyl forms, and oxo/hydroxy.
Includes m8a, m8b, m8c, m8d, m8e, m8f, m8g, m8h, m8i, m8j, m8k1, m8k2, m8k3, m8l1: 0 to 2 where specified.
- R9: H, substituted alkyl, alkenyl/alkynyl (with further substitutions via R9B/R9C), cycloalkyl/heterocycloalkyl (substituted), aryl, heteroaryl, CN, alkanoyl, nitrogen-containing heterocycloalkylcarbonyl, halogen, amino sulfonyl and carbonyl variants, nitro/hydroxy, and multiple alkoxy and alkoxycarbonyl/heterocycloalkyloxy forms, including sulfonyloxy and amino-substituted thio/sulfonyl variants.
Includes m9a, m9b, m9c, m9d, m9e, m9f, m9g, m9h: 0 to 2 where specified.
- R10: H or a substituted 4- to 10-membered heterocycloalkyl (in dependent claim 4 it is restricted; in claim 1 it is broader with CN, halogens, and heterocycloalkyl).
What does this mean in practical coverage terms?
The claim reads like a defensive publication of “peripheral substituent latitude” on a fixed benzo[b]carbazole-lactam/carbonitrile core. The independent claim 1 is not limited to one target molecule family member; it is a genus across many thousands of possible analogs, constrained only by the Markush definitions and the fixed core structural logic embedded in Formula (I).
How broad is claim 1 compared with dependent claim 2 to 4?
What do the independent narrowing dependent claims do?
- Claim 2: narrows claim 1 by setting R3 to either cyano or halogen.
- Claim 3: narrows by setting A5 = NR5 and R5 = hydrogen.
- Claim 4: narrows multiple variables at once:
- A1, A2, A3, A4, A7, A8, A9, A10 fixed as C; A5 in NR5/O/S (same high-level constraint but re-specified)
- R1 restricted to H, CN, or halogen
- R2 restricted to H, C1-8 alkyl, CN, halogen, and (C1-8 alkyl)-amino optionally sulfonylated (with m2: 0 to 2)
- R3 constrained relative to claim 1’s full set (still large but trimmed)
- R4 trimmed: H, C1-8 alkyl (with halogen option), cycloalkyl, CN, aminocarbonyl, hydroxycarbonyl, halogen, (alkyl)m4b-amino (m4b: 0 to 2), hydroxy, and alkoxy (with hydroxy option)
- R5 trimmed: H, alkyl (with R5A including hydroxycarbonyl/alkoxycarbonyl/hydroxy/alkoxy/(alkyl)m5-amino/alkylthio where m5: 0 to 2), or alkylsulfonyl
- R6/R6′ constrained to alkyl or cycloalkyl or heterocycloalkyl
- R7 constrained to H, halogen, substituted alkoxy (with amino substitution via m7a: 0 to 2)
- R8 constrained to a still-large subset but more bounded than claim 1
- R9 constrained to a subset
- R10 restricted to H or substituted heterocycloalkyl (4 to 10-membered), optionally substituted by additional heterocycloalkyl groups
Bottom line: Claim 1 is the genus. Claims 2 and 3 define sub-genuses by selecting two high-impact positions (R3 and A5/R5). Claim 4 locks additional positions to narrower sets while maintaining a broad analog space.
What do the listing-dependent claims cover?
Claims 5 through 29 list named exemplars, each defined as a benzo[b]carbazole carbonitrile compound with:
- a “6,6-dimethyl” motif (present in every named claim),
- an “11-oxo” motif (present in every named claim),
- a specific substituent pattern at “9” and “8,” and
- either a nitrile at “3-carbonitrile” (implied by the name fragment “-3-carbonitrile” / “-carbonitrile”).
What is common across claims 5-29?
All listed compounds contain the benzo[b]carbazole core fragment:
- “6,6-dimethyl-…-6,11-dihydro-5H-benzo[b]carbazole-3-carbonitrile”
and most include:
- “11-oxo”
and variable “8-(substituted piperazine/piperidine/morpholine/pyrrolidine/cyclobutyl/piperidinyl/oxetanyl)**” and “9- substituent (bromo/ethyl/ethynyl/cyclopropylethynyl/cyclobutyl-based etc.)”
Exemplars (claims 5-29)
| Claim |
Example compound name (key structural points) |
“8” substituent class |
“9” substituent class |
| 5 |
9-(4-isopropyl-piperazin-1-yl)-6,6-dimethyl-11-oxo-…-benzo[b]carbazole-3-carbonitrile |
Piperazine substituted with iPr |
4-isopropyl piperazine at 9 |
| 6 |
6,6-dimethyl-8-(4-oxetan-3-yl-piperazin-1-yl)-11-oxo-9-prop-1-ynyl-…-carbonitrile |
Oxetane-3-yl substituted piperazine |
Prop-1-ynyl |
| 7 |
9-cyclopropylethynyl-…-8-(4-oxetan-3-yl-piperazin-1-yl)-… |
Oxetane-3-yl piperazine |
Cyclopropylethynyl |
| 8 |
6,6-dimethyl-8-(1-oxetan-3-yl-piperidin-4-yl)-11-oxo-…-carbonitrile |
Oxetane-3-yl substituted piperidinyl |
(implicit none, since 9 position not shown) |
| 9 |
9-bromo-…-8-(4-oxetan-3-yl-piperazin-1-yl)-… |
Oxetane-3-yl piperazine |
Bromo |
| 10 |
9-bromo-8-(4-cyclopropyl-piperazin-1-yl)-…-carbonitrile |
Cyclopropyl-piperazine |
Bromo |
| 11 |
9-chloro-8-(4-morpholin-4-yl-piperidin-1-yl)-…-carbonitrile |
Morpholinyl piperidinyl |
Chloro |
| 12 |
8-(4-cyclobutyl-piperazin-1-yl)-…-9-prop-1-ynyl |
Cyclobutyl piperazine |
Prop-1-ynyl |
| 13 |
6,6,9-trimethyl-8-(4-morpholin-4-yl-piperidin-1-yl)-… |
Morpholinyl piperidinyl |
Methyl at 9 |
| 14 |
9-ethyl-8-(4-oxetan-3-yl-piperazin-1-yl)-… |
Oxetane-3-yl piperazine |
Ethyl |
| 15 |
9-ethyl-8-(4-morpholin-4-yl-piperidin-1-yl)-… |
Morpholinyl piperidinyl |
Ethyl |
| 16 |
9-ethynyl-8-(4-oxetan-3-yl-piperazin-1-yl)-… |
Oxetane-3-yl piperazine |
Ethynyl |
| 17 |
8-(4-cyclobutyl-piperazin-1-yl)-9-ethyl-… |
Cyclobutyl piperazine |
Ethyl |
| 18 |
9-ethynyl-8-(4-pyrrolidin-1-yl-piperidin-1-yl)-… |
Pyrrolidinyl piperidinyl |
Ethynyl |
| 19 |
6,6-dimethyl-11-oxo-8-(4-pyrrolidin-1-yl-piperidin-1-yl)-… |
Pyrrolidinyl piperidinyl |
(implicit none) |
| 20 |
8-(4-cyclobutyl-piperazin-1-yl)-9-ethynyl-… |
Cyclobutyl piperazine |
Ethynyl |
| 21 |
8-(4-cyclobutyl-piperazin-1-yl)-…-9-propyl |
Cyclobutyl piperazine |
Propyl |
| 22 |
8-(1-isopropyl-piperidin-4-yl)-… |
Isopropyl piperidinyl |
(implicit none) |
| 23 |
8-(4-isopropyl-piperazin-1-yl)-… |
Isopropyl piperazine |
(implicit none) |
| 24 |
8-(4-cyclobutyl-piperazin-1-yl)-9-cyclopropyl-… |
Cyclobutyl piperazine |
Cyclopropyl |
| 25 |
8-(2-tert-butylamino-ethoxy)-… |
Amino-ethoxy substituent |
(implicit none) |
| 26 |
9-ethynyl-8-(4-methanesulfonyl-piperazin-1-yl)-… |
Methanesulfonyl piperazine |
Ethynyl |
| 27 |
9-bromo-8-(4-cyclobutyl-piperazin-1-yl)-… |
Cyclobutyl piperazine |
Bromo |
| 28 |
6,6-dimethyl-8-(4-oxetan-3-yl-piperazin-1-yl)-11-oxo-9-propyl |
Oxetane-3-yl piperazine |
Propyl |
| 29 |
9-ethynyl-8-morpholin-4-yl-… |
Morpholinyl (directly on core) |
Ethynyl |
Interpretation for freedom-to-operate: The exemplars show that the “real” commercial chemistry expected by the applicant sits in a narrow chemical design space within the far broader Markush genus. If you are evaluating competitive entry with close analogs, these named compounds tell you which combinations the drafter treated as the most relevant.
Scope mapping: which variables appear to drive the medicinally relevant differentiation?
Which substituent families dominate the named compounds?
Across claims 5 to 29, the differentiators repeatedly fall into four buckets:
-
9-position substituents
halogens (Br, Cl), unsaturated linkers (ethynyl, prop-1-ynyl), and small alkyl/cycloalkyl (ethyl, propyl, cyclopropyl, cyclopropylethynyl).
-
8-position “solubilizing” amine-bearing substituents
piperazine derivatives (including oxetane-3-yl, cyclobutyl, cyclopropyl, methanesulfonyl, isopropyl), piperidine/pyrrolidinyl piperidines, morpholine/morpholinyl piperidine, and an ether-linked tert-butylamino motif.
-
Fixed polarity/structural motifs
6,6-dimethyl and 11-oxo appear invariant, consistent with a pharmacophore element rather than a variable.
-
Backbone unsaturation patterns
ethynyl/prop-1-ynyl appear paired with the oxetane-3-yl piperazine in multiple examples, suggesting a favored electronic/geometric arrangement.
Patent landscape analysis: what can be concluded from the provided record?
No filing history, publication number, assignee, priority data, prosecution events, claim set evolution, family members, or cited documents are provided for US 9,126,931. Without those, a complete landscape analysis (competing patents, overlap families, continuation coverage, blocking patents, or coexistence zones) cannot be produced from the claim text alone.
The only landscape conclusions that can be stated from the claim set you provided are structural and strategic:
What is the likely “center of gravity” of IP coverage?
Given the genus claim (1) with the expansive Markush definitions and the set of 25+ named compounds (5-29), the patent is built to defend:
- both direct structural variants (substitute at 8 and 9 positions with different amine solubilizers and halo/alkyl/alkynyl groups), and
- broader formal genus coverage that captures additional analogs beyond the named exemplars, as long as they fit the variable definitions in Formula (I).
Where do design-arounds likely fail quickly?
Design-arounds likely fail when they:
- retain the benzo[b]carbazole core with carbonitrile motif and the 11-oxo/6,6-dimethyl scaffold, and
- keep the same type of peripheral substitution patterns mapped by R variables (particularly the 8-position amine-bearing heterocycles and 9-position halogen or small unsaturation/alkyl).
Where design-arounds can create real legal distance
To create meaningful legal distance, an alternative would need to fall outside the structural restrictions implicit in Formula (I) and/or outside multiple R-variable ranges simultaneously. From the claim alone, “simple” changes like swapping one halogen for another may still land within R1/R3/R4/R7/R9 option sets depending on the specific position mapping.
Claim strength indicators for enforceability (based on claim drafting only)
What drafting characteristics increase the enforceable reach?
- Genus breadth in claim 1: the claim uses large Markush sets across nearly every peripheral position.
- Explicit inclusion of salts and solvates: expands practical coverage.
- Dependent claims lock specific embodiments: claim 5-29 list concrete structures, which often helps support enablement and written description for at least those members.
What drafting characteristics create litigation friction?
The claim’s Markush density is high. In practice, disputes often shift to:
- claim construction over position mapping within Formula (I), and
- whether particular alleged products fit the Markush definitions exactly.
Key Takeaways
- US 9,126,931 is a broad genus patent on benzo[b]carbazole carbonitrile compounds with “6,6-dimethyl” and “11-oxo” motifs, covering compounds, salts, and solvates through Formula (I) Markush variables.
- Claim 1 drives coverage via expansive substituent latitude at positions mapped by R1 through R10 and A1 through A10, including heteroatom option at A5 (NR5, O, S).
- Claims 2-4 narrow sub-genuses by fixing high-impact variables (R3; A5/R5; and a multi-variable restriction set in claim 4).
- Claims 5-29 focus exemplars on substituent patterns at the 8 and 9 positions, dominated by piperazine/piperidine/morpholine-like amine-bearing substituents and 9-position halogens or alkyl/alkynyl groups.
- Landscape limitations: without family/prosecution/publication/assignee/citation data, no complete cross-patent landscape can be built from the provided record. The landscape that can be inferred from this patent is structural: the design space it blocks is the Formula (I) genus anchored on this scaffold.
FAQs
Is claim 1 limited to any single benzo[b]carbazole substitution pattern?
No. Claim 1 is a Markush genus defined by Formula (I) with many substituent options at R1-R10 and heteroatom option at A5. It is only constrained by those definitions and the fixed A1/A2/A3/A4/A7/A8/A9/A10 = C assignments.
Do the listed claims (5-29) narrow the patent coverage or just provide examples?
They do both. They are dependent claims that narrow within the scope of claim 1 to specific named embodiments, while also providing concrete coverage anchors that reflect preferred substitution patterns (notably at the 8 and 9 positions).
Which variables are most strategically important for potential design-arounds?
R1/R3/R4/R7/R8/R9 are the primary levers because they govern peripheral substituent types (including halogens, cyano, hydroxy/alkoxy, heterocycles, and multiple carbonyl/aminosulfonyl/aminocarbonyl oxy groups) across the Formula (I) scaffold.
Does the patent cover salts and solvates?
Yes. The preamble of claim 1 and the dependent structure in claims 2-4 and the embodiment claims explicitly include “a compound or salt or solvate.”
Can the broader claim be considered to cover only what is exemplified?
No. The genus in claim 1 is not restricted to the exemplified list. The exemplars inform the likely intended scope, but the legal scope follows the Markush definitions in claim 1.
References
[1] US Patent 9,126,931 (claims text provided in prompt).
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