approach to the use of racemic amp; alpha; - hydroxy - amp; beta;, amp; beta; dimethyl amp; gamma; - butyrolactone in the optically active and their counterparts.

摘要

A process for resolving D,L-pantolactone uses as the resolving agent a 1,4a -dimethyl-7-isopropyl-octahydro-, dodecahydro-, or per-hydrophenanthrene derivative which is substituted at the 1-position with a -NH2 or -CH2NH2 group. The salts of a ,q -dihydroxy-b b -dimethyl butyric acid with the above bases, formed during the resolution, are claimed per se. Preferably, the sodium salt of a racemic mixture of this acid is first formed from the pantolactone and is reacted with 55 to 57 molar per cent of the phenanthrene derivative hydrochloride. At equilibrium the L-( - )-salt of the phenanthrene derivative precipitates. Thus D-( - )-pantolactone may be formed from the D-( + )-sodium salt left in solution by acidification, and L-( + )-pantolactone may be formed via its sodium salt, and then racemized to form fresh starting material. Exemplified amines of the above formula used for the resolution are the D 5, D 7, D 46-8a octahydro, D 8 dodecahydro and perhydro derivatives.