1, 2-Diaza-1, 3-butadienes have been obtained from readily available 3-hydroxy-2- arylhydrazonopropanoates under various reaction conditions including pyrolysis, dehydration under Mitsunobu conditions or with acetic anhydride or acetic acid. According to their method of synthesis these 1, 2-diaza-1, 3-butadienes underwent subsequent reactions to give interesting products, and in the presence of proper dienophiles gave the ...