What is the patent “spiro synthesis” asking for in rolapitant?
“Rolapitant patent spiro synthesis” is typically a search phrase for the synthetic route in a patent document that builds a spirocyclic intermediate or final spiro-containing structure used to make rolapitant (or a closely related intermediate). In patents, “spiro synthesis” usually refers to the step(s) where a spiro ring system is formed (often via cyclization/annulation), followed by functional group installation and purification described by example procedures.
Which patents actually cover rolapitant spiro intermediates?
To identify the exact “spiro synthesis” section, you need the specific rolapitant patent number (or a document link/Pub. number such as WO/EP/US). Different filings cover different parts of the molecule’s route:
- routes to key intermediates (including spiro building blocks),
- routes to the finished API (rolapitant),
- polymorph/crystal forms (which usually do not include spiro-forming chemistry),
- process improvements (alternative ways to make the same intermediates).
If you share a patent number (or the WO/US/EP publication), I can point you to the relevant claims and the example(s) that contain the spiro-forming step.
What does a spiro-forming step look like in patents (typical mechanisms)?
In rolapitant-related chemistry, a spiro formation step in a patent often comes in the “intermediate preparation” examples and is written as a sequence such as:
- preparing a precursor with the two ring-forming elements,
- activating one part (e.g., with a leaving group or reagent),
- intramolecular cyclization to close one ring,
- conditions that drive formation of a spiro center,
- workup and purification to isolate the spiro intermediate before coupling/derivatization.
Patents differ on the exact reagent set and conditions, so the correct answer depends on the exact document you mean by “Rolapitant patent.”
How to find the spiro synthesis part quickly inside the patent
Once you have the publication:
1. Search within the PDF for terms like “spiro”, “spiro[”, “spirocyclic”, “cyclization”, or the exact intermediate name if it’s defined in the claims.
2. Check “Examples” sections first; spiro chemistry is usually in Example 1/2/3 style intermediate preparations.
3. Match the intermediate numbering in the scheme (e.g., “Intermediate X”) to the table/claim that defines what it’s used for later.
What I need from you to give the exact spiro synthesis steps
Send one of the following:
- the rolapitant patent publication number (WO/EP/US) or link, or
- the patent title + assignee, or
- the intermediate number/name from the patent that contains “spiro”.
Then I can extract the spiro synthesis procedure as written (reagents, order of addition, temperatures, times, yields, and purification), and explain how it fits into the overall rolapitant synthesis route.