preparation of natural products and complex biologically active compounds and the construction of selective drugs.' Our current research interest has focused on the reactions of 0-pivaloyl-D-glucopyranosylaldimines, and especially on their use in the stereoselective synthesis of a-amino acids. Opticallyactive a-amino acids may be obtained by the asymmetric Strecker reaction of imines. Kunz' group have reported
New derivatives of 2-(1-amino-1-phenylmethyl)-1,3,4-oxadiazole and 1,2,4-triazin-6-one were synthesised in the reactions of opticallyactive α-aminocarboxylic acid hydrazides and triethyl orthoesters in xylene. The electronic and steric effects of substituents at the α position influencing the formation of five- or six-membered products are discussed.