Optical resolution of threo-2-hydroxy-3-(2-aminophenylthio)-3-(4-methoxyphenyl)-propionic acid
US5302741A · kind A · utility
1Cited by
4References
15Claims
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Key dates
| Filing date | Jul 12, 1993 |
| Grant date | Apr 12, 1994 |
| Priority date | — |
| Expiry date | Jul 12, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C323/56
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
D(+)-threo-2-hydroxy-3-(2-aminophenylthio)-3-(4-methoxyphenyl)propionic acid, an important intermediate in the synthesis of diltiazem hydrochloride, is obtained in better yields and high optical purity by a novel resolution process comprising the reaction of 2 moles of the (.+-.) racemic acid with 1 mole of quinine and 1 mole of a base in a suitable polar solvent system to form a salt of the D(+) acid and quinine which precipitates; separating said salt and decomposing it with a strong base.
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