What is rolapitant, and what does “spiro” refer to in its patent landscape?
Rolapitant is an NK1 (neurokinin-1) receptor antagonist used as an antiemetic, typically in the setting of chemotherapy-induced nausea and vomiting. Patent documents about rolapitant often describe the drug’s chemical structure and how it is synthesized, including the formation of ring systems.
In this context, “spiro” usually points to a “spiro” ring motif in the chemical structure—i.e., a spiro-fused ring arrangement where two rings share a single atom. That motif matters for patents because it typically drives the key steps in synthetic routes (forming the spiro center and building the fused ring geometry).
How do patents usually describe rolapitant “spiro” synthesis?
Patent synthesis sections typically do three things relevant to “spiro” references:
- They define the specific intermediate numbering and exact structural form for the spiro-containing scaffold.
- They specify how the spiro center is constructed (often through cyclization or ring-forming steps using a suitably functionalized precursor).
- They state conditions for key transformations (reagents, catalysts, solvents, temperatures) that control regio- and stereochemical outcomes needed to match the rolapitant scaffold.
If you’re looking for a specific patent synthesis write-up, the term “spiro” will usually appear close to descriptions of those cyclization/intermediate-forming steps rather than in salt-forming or final purification.
Which patents are most likely to contain rolapitant “spiro” synthetic procedures?
The strongest chance of finding “spiro” synthesis language is in:
- Original composition-of-matter filings that describe the full chemical structure and include representative preparations.
- Process patents or granted patents focused on improved manufacturing routes, especially for hard-to-make intermediates.
- Claims and examples that cover “intermediates” leading to the final spiro-containing core.
To pinpoint the exact documents, you generally need at least one of: a patent family name, assignee, application number, or an exact quote/snippet containing “spiro”.
What does a “spiro” motif change in the chemistry (and why patents care)?
A spiro center and spiro-fused geometry can materially affect:
- The feasibility of cyclization steps (different precursors are required to reach the shared atom and ring closure geometry).
- Yield and impurity profile (side reactions often increase when forming spiro junctions).
- Stereochemical control and conformational constraints (enzymatic and receptor-binding properties can depend on the exact 3D arrangement).
Patents care because process claims and intermediate claims can hinge on how the spiro scaffold is made and which intermediates are used.
Can you paste the specific text you saw (or the patent number) so I can synthesize it accurately?
Your query is too fragmentary to identify the exact rolapitant patent and the specific “spiro” synthesis being referenced. If you share any of the following, I can produce a precise synthesis-style patent summary:
- Patent publication number (e.g., WO/EP/US + number) or application number
- Assignee/company name
- A short excerpt that contains “spiro”
- The intermediate name/number used in the example (patents often label intermediates as “Intermediate X”)
Sources
No sources were provided in your message, and there’s not enough information to reliably cite specific rolapitant “spiro” patents.