Process for resolving the enantiomers of a benzopyran derivative
US4952696A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 14, 1990 |
| Grant date | Aug 28, 1990 |
| Priority date | — |
| Expiry date | Feb 14, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D405/04
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a process for resolving the enantiomers of trans-3-hydroxy-3,4-dihydro-2,2-dimethyl-4-(2-oxo-1,2-dihydropyridin-1-yl) -2H -1-benzopyran-6-carbonitrile (I), characterized in that racemic I, together with a small amount of (-)-I [or (+)-I], is dissolved in an inert solvent or solvent mixture, the solution is seeded with (-)-I [or (+)-I], the (-)-I [or (+)-I] which has precipitated is isolated, further racemis I is dissolved in the filtrate, the mixture is seeded with (+)-I [or (-)-I], the (+)-I [or (-)-I] which has precipitated is isolated, and if desired this crystallization cycle is repeated once or several times.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.