Abstract
Reaction of the 3-dimethylamino-2,2-dimethyl-2H-azirine (1) with salicylic acid hydrazide (2c) in acetonitrile at room temperature gives the amidrazone 3a as a primary product in 78% yield. Cyclization of 3c in methanol leads to the 1,2,5,6-tetrahydro-1,2,4-triazin-6-one 4, whereas the cyclization in DMSO gives a mixture of 4 and the 5-dimethylamino-2,4-dihydro-1,2,4-triazine 5. Benzoic acid hydrazides of type 6 react with 1 in acetonitrile at 80 °C to give the 1,3,4-oxadiazoles of type 7 in good yield.
Chaloupka, Stanislav