The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 28, 1990
Filed:
Feb. 14, 1990
Ralf M Devant, Darmstadt-Arheilgen, DE;
Merck Patent Gesellschaft mit Beschraenkter Haftung, Darmstadt, DE;
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.