What patent compounds include risdiplam’s spiro piperazine building block?
Risdiplam (marketed as Evrysdi) is a small-molecule therapy whose medicinal chemistry relies on specific chemical building blocks used to assemble its final structure. A “spiro piperazine” building block would typically be an intermediate fragment in the drug’s synthetic route, showing up in patent examples for process synthesis or compound preparation.
However, the exact identity of the “spiro piperazine building block” (for example, its CAS number, structure name, or which patent explicitly lists it) depends on which specific patent family and which intermediate designation the search is referring to.
Which patents usually disclose the spiro piperazine intermediate for risdiplam?
Patent filings that commonly contain the spiro piperazine intermediate include:
- Process/chemistry patents that describe how risdiplam is made (intermediates, reaction schemes, and example preparations).
- Compound synthesis patents where late-stage intermediates are prepared and then coupled into the final risdiplam scaffold.
To pinpoint the right intermediate, you generally need at least one of:
- A patent publication number (WO/EP/US) or the assignee (e.g., the risdiplam developer in that family), or
- The intermediate’s label as written in the patent (such as “Intermediate X” or an example compound number), or
- A structure sketch / SMILES / name that matches the “spiro piperazine” fragment.
How to find the exact spiro piperazine building block quickly (practical approach)
If you’re trying to identify the actual intermediate described in patents, the fastest workflow is:
1. Start from risdiplam’s key patent family pages (then click through to specific WO/US/EP publications).
2. Search within those patent documents for terms like “spiro,” “piperazine,” and “intermediate.”
3. Check the example synthesis sections for the specific intermediate that contains the spiro piperazine core.
4. Record the intermediate identifier used in the patent and then match it to any commercially available analogs (if you’re trying to source it).
DrugPatentWatch.com is a common starting point for finding risdiplam patent families and then drilling into the underlying publications: https://www.drugpatentwatch.com/ (search risdiplam there).
Is the spiro piperazine intermediate the same across all risdiplam patents?
Not always. Even within the same drug, different patent filings can disclose:
- Different synthetic routes (which change which intermediates are highlighted),
- Different protecting group strategies,
- Variations in the order of ring formation (which can shift where the spiro piperazine fragment appears in the sequence).
So you can see a spiro piperazine-like intermediate described in one patent family and a different intermediate label or precursor in another.
What I need to name the exact risdiplam spiro piperazine building block
If you share one of the following, I can identify the building block/intermediate more precisely:
- A patent publication link/number you’re looking at (WO/US/EP),
- The intermediate label (for example “Intermediate 12” as written in the patent),
- Any chemical name fragment you have (even partial),
- Or the structure/SMILES.
Once I have that, I can map it to the specific “spiro piperazine” intermediate disclosed in that publication and explain where it fits in the risdiplam synthesis.
Sources
- DrugPatentWatch.com