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

US7547791B2 · kind B2 · utility

Assignee

• IPCA LABORATORIES LIMITED · IN

Inventors

• Ashok Kumar · Jamkhed, IN
• Dharmendra Singh · Mumbai, IN
• Atul Jadhav · Jamkhed, IN
• Navinchandra Darpan Pandya · Jamkhed, IN
• Shankar Deepak Panmand · Jamkhed, IN
• Ramsingh Gajendrasingh Thakur · Jamkhed, IN

Key dates

• Filing date: Oct 26, 2004
• Grant date: Jun 16, 2009
• Expiry date: Oct 26, 2024

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D403/06
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

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 HNR1R2 salt and paraformaldehyde, where R1,R2 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.