Synthesis and Reactions of Some 4-Chloro-4-alkoxycarbonyl-1,2-diaza-1,3-butadienes

The synthesis and some reactions of unknown 4-chloro-4-alkoxycarbonyl-1,2-diaza-1,3-butadienes are reported. In particular, the preparation of new 4,4-dichloro- and 4,4-dimethoxy-1H-pyrazol-5(2H)-one, as well as 4-chloro-5-alkoxypyrazole derivatives is described.