A ONE-POT PROCESS FOR THE PREPARATION OF ANTIEMETIC AGENT, 1,2,3,9-TETRAHYDRO-9-METHYL-3[(2-METHYL)-1H-IMIDAZOLE-1-YL)METHYL]-4H-CARBAZOL-4-O

摘要

A one-pot industrial process for preparing 1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazole-1-yl)methyl]-4H-carbazol-4-one of Formula-(I) from 1,2,3,9-tetrahydro-9-methyl-4H-carbazol-4-one of Formula-(IV) involves reaction of Formula (IV) with HNR<SUB>1</SUB>R<SUB>2</SUB> salt and paraformaldehyde, where R<SUB>1</SUB>,R<SUB>2</SUB> are independently alkyl groups or together forms a cyclic alkyl group, in a solvent system of acetic acid and hydrocarbon solvent to form a crude mixture of intermediate compounds of Formula (III) and (VIII), which is converted to ondansetron (Formula (I)) without isolation by reaction with 2­methyimidazole in a suitable solvent system in the same pot.