Cyclization of the hydrazide of 5-ethoxycarbonyl-2, 6-dimethylpyridine-3-carboxylic acid by acylation with aromatic or aliphatic acid chlorides with subsequent boiling in POCl 3 or heating in orthoformic acid gave the corresponding ethyl 2, 6-dimethyl-5-(5-R-1, 3, 4- oxadiazol-2-yl) pyridine-3-carboxylate. The cyclization of the reaction products with hydrazine hydrate has been studied. Cyclization of the dihydrazide of 2, 6-dimethyl-3, 5- ...
