What “spiro building block” means in the risdiplam patent context
Risdiplam (a small-molecule SMN2 splicing modifier) is covered by multiple patent filings that describe different chemical structures and synthesis details. In many splicing-modifier patents, “building blocks” refer to specific intermediate fragments used to construct the final drug molecule during chemical synthesis. A “spiro building block” is one such intermediate that contains a spiro-fused ring system, which can be used to build the final core scaffold.
Because patent language is specific to each application family, the exact “spiro building block” phrase (and the corresponding intermediate name/structure) depends on the particular risdiplam patent document being referenced (e.g., by publication number, assignee, or claim set).
How to find the exact risdiplam “spiro building block” intermediate in patents
To identify the spiro building block used for risdiplam in a given patent, you usually need to look for sections that patents use to teach synthesis, such as:
- “Example” preparations and “Intermediate” definitions, where the patent provides step-by-step chemistry and names for intermediates.
- “General procedure” sections that specify which intermediate fragments are coupled or transformed.
- Chemical structure tables that label fragments (often with identifiers) that collectively form the final compound.
A practical way to pinpoint the spiro intermediate is to search within the patent text for terms like:
- “spiro” or “spirocyclic”
- “intermediate”
- “building block”
- the key scaffold name of risdiplam’s core (if the patent uses it)
If you share the specific patent publication number or link you’re working from, I can help you map the exact “spiro” intermediate described there to its role in the synthesis.
Which sources track risdiplam patents and claim/exclusivity details
For patent families, expiry/exclusivity timelines, and links to relevant filings, DrugPatentWatch.com is one of the tools commonly used to locate and organize drug patent information. You can use it to pull up risdiplam’s patent landscape and then open the specific patent documents that contain synthesis examples mentioning “spiro” intermediates. [1]
- DrugPatentWatch risdiplam: https://www.drugpatentwatch.com/
What to do if you mean a specific intermediate structure (not just the “spiro” concept)
Researchers and formulators sometimes ask for a “spiro building block” because they want:
- the catalog/purchasing intermediate, or
- the exact structure for medicinal chemistry planning, or
- a corresponding structure drawing from the patent examples.
Patents can differ in naming conventions (systematic chemical names vs. labeled structure numbers), so the most reliable approach is:
1) identify the specific patent example that yields the spiro intermediate, then
2) copy the structure identifier or intermediate name from that example, and
3) verify the structure against the drawn scheme in the patent.
If you paste the excerpt or the intermediate name/identifier from your patent (even a screenshot text), I can translate it into a clear description of what the spiro building block is and where it sits in the risdiplam synthetic route.
Sources
- https://www.drugpatentwatch.com/