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US 10,329,254 B2Granted
Process for the preparation of 6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide and intermediates thereof
AssigneeAop Orphan Pharmaceuticals AG
InventorsEnrica Diodato, Katia Marcucci, Russell Thomas, Paul Wiedenau, Martin Rettig, Huw Roberts
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Abstract
The invention relates to a novel process for the preparation of rac-6-Chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide (I) in pharmaceutically acceptable polymorphic form, through the conversion of a 3-bromo-2-oxo-cyclohexanecarboxylic acid alkyl ester into 6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxylic acid alkyl ester, which in turn is processed to yield the final product.
Claims18
A process for the preparation of compound (I′-b) on a kg-scale and larger, wherein compound (I′-b) is prepared according to the following scheme:
- wherein R is a C1-C6 linear alkyl chain, C1-C6 branched alkyl chain, or cycloalkyl,
- said process being characterised in that the reaction between (I′-a) and 4-chloroaniline is performed under heating in a solvent which forms an azeotropic mixture with water, and wherein the ensuing water is removed by azeotropic distillation.
Dependencies are inferred from the claim text.