Method for the preparation of 5-cyanophthalide
US6392060B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 2001 |
| Grant date | May 21, 2002 |
| Priority date | — |
| Expiry date | Jun 22, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D307/88
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A method for the preparation of 5-cyanophthalide in which 5-carboxyphthalide is converted to the corresponding amide of Formula (IV) in which R is hydrogen or C1-6 alkyl, which is then reacted with a dehydrating agent thereby obtaining 5-cyanophthalide. The conversion of 5-carboxyphthalide to the corresponding amide of Formula (IV) may be carried out via the corresponding C1-6 alkyl or phenyl ester or the acid chloride, which is converted to the amide of Formula (IV) by amidation with ammonia or a C1-6 alkylamine. By the process 5-cyanophthalide, an important intermediate used in the preparation of the antidepressant citalopram, is prepared in high yields by a convenient, cost effective procedure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.