Reaction of alkyl 3-bromo-3-nitroacrylates with substituted hydrazines. Synthesis of N′-substituted alkyl 3-nitropyruvate hydrazones

The reaction of alkyl 3-bromo-3-nitroacrylates with substituted phenylhydrazines and hydrazides of aromatic acids proceeds through the formation of aza-Michael adducts. Their subsequent dehydrohalogenation with Et3N affords N′-substituted hydrazones of alkyl 3-nitropyruvates. A one-pot synthesis of these compounds was developed. The synthesized hydrazones have a Z configuration, which was confirmed by 1H NMR spectroscopy and X-ray diffraction.