1-(Ethoxycarbonyl)-3-butylidene-(6-chloro-3-pyridazinyl)hydrazine 4-(2-(6-Chloro-3-pyridazinyl)hydrazinylidene)valeric acid ethyl ester 5-25-17-00363 (Beilstein Handbook Reference) 69579-23-3 BRN 0920285 GYKI 11628 Pentanoic acid, 4-((6-chloro-3-pyridazinyl)hydrazono)-, ethyl ester Valeric acid, 4-(2-(6-chloro-3-pyridazinyl)hydrazinylidene)-, ethyl ester