Process for the preparation of high-purity 1-(3-chloro-phenyl)-4-methyl-7,8-dimethoxy-5H-2,3-benzodiazepine
US5288863A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 4, 1992 |
| Grant date | Feb 22, 1994 |
| Priority date | — |
| Expiry date | May 4, 2012 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61P25/00
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a process for the preparation of 1-(3-chlorophenyl)-4-methyl-7,8-dimethoxy-5 H-2,3-benzodiazepine of formula (I) ##STR1## in high purity and in a quality suitable for pharmaceutical purposes. According to the invention the reaction of 1 mole of 2-acetonyl-3'-chloro-4,5-dimethoxybenzophenone of formula (II) ##STR2## with 3-7 moles of hydrazine hydrate in an organic solvent or in a mixture of organic solvents at a temperature between 15.degree. C. and 85.degree. C. is carried out in the absence of air oxygen, optionally in the presence of water. The crude product is then recrystallized from an aliphatic alcohol containing 1 to 5 carbon atom(s).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.