A Practical Synthesis of Optically Active Platelet-Activating Factor Antagonist, (+)-6-(2-Chlorophenyl)-3-cyclopropanecarbonyl-8,11-dimethyl-2,3,4,5-tetrahydro-8H-pyrido[4', 3' : 4,5]thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine (E6123), and Its Absolute onfiguration

Optically active platelet-activating factor (PAF) receptor antagonist, (+)-6-(2-chlorophenyl)-3-cyclopropanecarbonyl-8,11-dimethyl-2,3,4,5-tetrahydro-8H-pyrido[4', 3' : 4,5]thieno[3,2-f][1,2,4]triazolo[4,5-a][1,4]diazepine (E6123), was synthesized on large-scale by optical resolution using (+)-dibenzoyl-D-tartaric acid. An X-ray crystallographic analysis clearly indicated that the absolute configuration of the synthesized E6123 was S.