ENZYMATIC OPTICAL RESOLUTION OF DIBENZOXEPINS AND ITS APPLICATION TO AN OPTICALLY-ACTIVE ANTIALLERGIC AGENT WITH THROMBOXANE-A2 RECEPTOR ANTAGONISTIC ACTIVITY

Methyl l)thio-6,11-dihydrodibenzb,e!oxepin-2-carboxylate (5) was enan tio-selectively acylated with acetic anhydride in an organic medium by Lipase Amano P to give methyl l)thio-6,11-dihydrodibenzb,e!oxepin-2- carboxylate (8), and the (+)-enantiomer by Lipase Sigma Type VII. Usin g Lipase Amano P, (+)- and (-)-(5) could be prepared with high optical purity (84-94% e.e.). These products were respectively converted to ( +)- and (-)-KW-4099, which had antiallergic activity with complete ret ention of the optical purity.