Details for Patent: 5,587,497

US Patent 5,587,497: Scope, Claims, and US Landscape

What does US Patent 5,587,497 claim in plain chemical terms?

US 5,587,497 claims a family of “vitamin D” analog compounds defined by a broad structural Markush scaffold. The core claim language covers:

• A compound with a defined set of substitutions (variables X1, X2, R, R1-R7, n) on a vitamin D-like secosteroid framework (the structures are provided as embedded formula images in the claim text you supplied).
• A special proviso that changes the independence of substituents when n takes values 2 to 5.
• Multiple dependent claims that narrow to specific substitution patterns.
• Final dependent claims that identify specific marketed-style structures (names) corresponding to 1α-hydroxy / 1α,25-dihydroxy-19-nor vitamin D series, including D3, D2, and 24-epi variants.

How broad is Claim 1?

Claim 1 is the main scope driver. It is broad because it is written as a Markush set across multiple substitution points and functional classes:

Variable framework and permitted classes (Claim 1)

Claim 1 defines a compound of formula (IMAGE: “##STR10##”) where:

A) X1 and X2

• Each of X1 and X2 is independently selected from:
  • hydrogen
  • acyl
  • alkylsilyl
  • alkoxyalkyl

B) R

• R is selected from:
  • alkyl
  • hydrogen
  • hydroxyalkyl (with 4 to 5 carbons)
  • fluoroalkyl
  • and a substituted “side chain” group of formula (IMAGE: “##STR11##”)

C) Side chain substitutions (IMAGE “##STR11##”) Within that side chain group:

• R1 = hydrogen, hydroxy, or O-acyl
• R2 and R3 = alkyl, hydroxyalkyl, or fluoroalkyl
  • or, when taken together, R2 and R3 represent --(CH2)m-- where m = 2 to 5
• R4 = hydrogen, hydroxy, fluorine, O-acyl, alkyl, hydroxyalkyl, or fluoroalkyl
  • or R4 and R5 taken together represent double-bonded oxygen
• R5 = hydrogen, fluorine, alkyl, hydroxyalkyl, or fluoroalkyl
• R6 and R7 = each hydrogen, hydroxy, O-acyl, fluorine, or alkyl
  • or R6 and R7 taken together form a carbon-carbon double bond
• n = integer 1 to 5
• Two linked stereochemical/positional modifications:
  • Any of the groups -CH(CH3)-, -CH(R7)-, or -CH(R6)- at positions 20, 22, 23 may be replaced by an oxygen atom
• Proviso (key narrowing mechanism)
  • When n is 2 to 5:
  • each R4 is independently selected from hydrogen, hydroxy, fluorine, O-acyl, alkyl, hydroxyalkyl, fluoroalkyl
  • each R5 is independently selected from hydrogen, fluorine, alkyl, hydroxyalkyl, fluoroalkyl

Practical effect: Claim 1 is “broad-by-design,” not just “generic”

The breadth comes from (i) multiple independent selection variables and (ii) allowance for structural “toggle points”:

• Side-chain diversity (R plus R1-R5 and m controls)
• Ring oxygen substitution option at positions 20, 22, 23
• Degree of saturation/unsaturation via R6/R7 double bond option
• n controls the side chain length or related scaffold parameter across 1 to 5

How does Claim 2 narrow scope?

Claim 2 is a heavily constrained subset of Claim 1:

• X1 and X2 = hydrogen
• R1 = hydroxy
• R2 and R3 each selected from methyl, trifluoromethyl, ethyl, propyl
• R6 and R7 are hydrogen or together form a carbon-carbon double bond
• R4 and R5 = hydrogen
• n = 1, 2, or 3

This converts the general Claim 1 breadth into a defined set of side-chain and oxygen/unsaturation patterns.

What do Claims 3–6 do?

Claims 3–6 are additional Markush selections that narrow “R” to specific side chain structural images:

• Claim 3: R is the side chain of ##STR12##
• Claim 4: R is the side chain of ##STR13##
• Claim 5: R is the side chain of ##STR14##
• Claim 6: R is the side chain of ##STR15##

Even without the images expanded in text, their function is clear: they select among the Claim 1 side-chain alternatives to land on particular classes intended to cover particular vitamin D analogs.

What do Claims 7–12 actually cover (specific compounds)?

Claims 7–12 are explicit compound claims as dependent claims to Claim 1.

Enumerated vitamin D analogs in Claims 7–12

Scope implication

These named compounds are effectively “anchor points” for the patent:

• If a competitor’s molecule fits the Claim 1 scaffold parameters, Claims 7–12 operate as captured specific embodiments.
• If a competitor’s molecule misses Claim 1 but matches the named compounds, the key question becomes whether the named structures are indeed within Claim 1’s Markush limits. Given they are dependent claims, the examiner and drafter treat them as covered embodiments of Claim 1.

Claim-set structure: where infringement risk concentrates

From a risk mapping perspective, infringement for US 5,587,497 will typically hinge on Claim 1’s scaffold fit first, then the exact match to a dependent claim if a generic structure is alleged.

Claim 1 coverage hotspots (high value for freedom-to-operate)

The most litigation-sensitive portions of the claim language are:

1. Side chain identity and allowed substitutions
   • Broad selection via R and side-chain formula options (R1-R5, m, fluoroalkyl/hydroxyalkyl classes)
2. Oxygen replacement at positions 20, 22, 23
   • Any of -CH(CH3)-, -CH(R7)-, -CH(R6)- at those positions may be replaced by oxygen
3. n parameter controlling the scaffold option
   • n = 1 to 5, with an explicit proviso for n = 2 to 5 that affects R4/R5 selection independence
4. Double bond toggles
   • R6/R7 can form a carbon-carbon double bond
   • R4/R5 can represent a double-bonded oxygen situation

What is the patent landscape around 19-nor vitamin D analogs in the US?

A complete, accurate landscape for US 5,587,497 requires citations to specific US patents, prosecution history, and/or patent family members. Your prompt provides the claim text but does not provide bibliographic data, priority date, assignee, inventors, filing/publication numbers, or the specification content needed to reliably connect this patent to the correct families and competing filings.

Because of that, no defensible competitive map, claim overlap analysis, or “who else owns what” can be produced without adding uncited external sources, which you have not provided.

How to interpret landscape value without other patents in hand

Even without the broader citation set, the patent’s internal structure indicates how it is likely positioned:

• It is written to cover both monohydroxy and dihydroxy 19-nor vitamin D variants in both D2 and D3 backbones.
• It includes a 24-epi subgroup (Claims 11–12), which typically narrows to stereochemical variants that can otherwise be treated as distinct IP targets.
• The heavy use of Markush variables suggests the patent is built to capture multiple side-chain analogs beyond the named final embodiments.

Key takeaways

• US 5,587,497 Claim 1 is the broad core: it uses Markush variables across X1/X2, side-chain classes (R, R1-R5, m), oxygen replacement at positions 20/22/23, and optional unsaturation patterns.
• Claims 2 and 3–6 progressively narrow to defined substitution patterns and specific side-chain images.
• Claims 7–12 lock specific named compounds: the patent explicitly claims 1α-hydroxy and 1α,25-dihydroxy 19-nor vitamin D variants including D3, D2, and 24-epi D2.
• Infringement risk analysis should start with Claim 1 scaffold fit, then check whether the competitor’s structure is encompassed by the proviso logic for n = 2 to 5, the oxygen replacement option at 20/22/23, and the double-bond toggles.

FAQs

1. Is Claim 1 limited to vitamin D2 or vitamin D3?
   No. Claim 1 is broad enough to include embodiments that map to both 19-nor vitamin D3 and 19-nor vitamin D2 series, as shown by dependent Claims 7–12.

2. What does the oxygen replacement language at positions 20, 22, and 23 change?
   It expands coverage by allowing certain carbon groups at those positions to be replaced with oxygen, creating additional structural variants within the same claim.

3. Does Claim 1 require hydroxy at R1?
   Not generally. Claim 1 allows R1 = hydrogen, hydroxy, or O-acyl, while Claim 2 tightens this to R1 = hydroxy.

4. Are double bonds optional in the claimed compounds?
   Yes. Claim 1 includes options where R6 and R7 together form a carbon-carbon double bond, and where R4 and R5 together can represent a double-bonded oxygen.

5. Which claims identify the most specific compounds?
   Claims 7–12 are the most specific because they name particular molecules (1α-hydroxy and 1α,25-dihydroxy-19-nor vitamin D variants, including 24-epi D2).

References

[1] US Patent 5,587,497 (claim text provided in prompt).