"Process for preparing the cyclohexylamine salt of (+) - threo-2-hydroxy-3-(2'-aminophenylthio) -3-(4""-methoxyphenyl) -propionic acid and of its (-) -antipode"""
US5710321A · kind A · utility
0Cited by
3References
5Claims
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Key dates
| Filing date | Apr 15, 1996 |
| Grant date | Jan 20, 1998 |
| Priority date | — |
| Expiry date | Apr 15, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C2601/14
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The present invention relates to a process for preparing the cyclohexylamine salt of (+)-threo-2-hydroxy-3-(2'-aminophenylthio)-3-(4"-methoxyphenyl)-propionic acid and of its optical (-)-antipode, by starting from the racemate acid by means of a first crystallization from a suitable chiral base and a second crystallization from a cyclohexylamine-containing solvent. Said salt is an intermediate in the synthesis of diltiazem, a well-known calcium-antagonist drug.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.