2-Butanone, (1-methylpropylidene)hydrazone 2-Butanone, azine 4-01-00-03252 (Beilstein Handbook Reference) 5921-54-0 BRN 0906883 Ethyl methyl ketone azine Methyl ethyl ketone azine Methyl ethyl ketone ketazine Methylethyl ketazine