STEREOCHEMICAL ASPECTS OF THE FORMATION OF DIASTEREOISOMERIC 3-ACETYL-2-(POLYACETOXYALKYL)-5-PHENYL-2,3-DIHYDRO-1,3,4-OXADIAZOLES

Article abstract of DOI:10.1016/0008-6215(88)84088-6

The synthesis of D- and L-3-acetyl-2--<(-)-and (+)-4a, (-)-4b> and 3-acetyl-2--5-phenyl-2,3-dihydro-1,3,4-oxadiazoles <(+)-4d> via cyclisation of the corresponding (O-acetylating conditions is described.The stereochemical aspects of the formation of C-2 epimeric oxadiazolines are discussed on the basis of optical rotation and n.m.r. data.The acetylation of methylglyoxal bis(benzoylhydrazone) (8) was found to give diastereoisomeric 1,3,4-oxadiazolines (12a and 12b) insteadof the bis(acetylbenzoylhydrazone) 9 claimed in the literature.