Synthesis of Some Hydrazone Derivatives Structurally Related to the Insecticide Pymetrozine

Reaction of pyridine-3-carbaldehyde methylhydrazone with 1,1'-carbonylbis-1H-imidazole afforded (E)-1'-methyl-2'-(3"-pyridyl) methylidene ]-1H-imidazole-1-carbohydrazide (2). Reaction of (2) with ethylamine, ethanol, ethanethiol, hydrazine monohydrate and methoxyamine afforded the corresponding semicarbazide, carbazate, thiocarbazate, carbonohydrazide and 4-methoxysemicarbazide derivatives (3a-d,g). Reaction of (2) with methylhydrazine gave the carbonohydrazide derivative (3f) together with 2,4-dimethyl-6-(3'-pyridyl)-1,4,5,6-tetrahydro-1,2,4,5-tetrazin-3(2H)-one (4a). The preparation of (E)-3-[(3'-pyridyl) methylideneamino ]oxazolidin-2-one (5a) and (E)-3-[(3'-pyridyl) methylideneamino ]tetrahydro-2H-1,3-oxazin-2-one (5b) is described.