Regioselective synthesis of ethyl pyrazolecarboxylates from ethyl 3??[(dimethylamino) methylidene] pyruvate and diethyl 3??[(dimethylamino) methylidene]??2?? …

…, J Svete, A Golobič, B Stanovnik

Index: Hanzlowsky, Andrej; Jelencic, Blanka; Recnik, Simon; Svete, Jurij; Golobic, Amalija; Stanovnik, Branko Journal of Heterocyclic Chemistry, 2003 , vol. 40, # 3 p. 487 - 498

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Citation Number: 30

Abstract

Abstract Reactions of ethyl 3-[(E)-(dimethylamino) methylidene] pyruvate (3) and 3- [(dimethylamino) methyl-idene]-2-oxosuccinate (4) with hydrazine monohydrochloride (5a) and (hetero) arylhydrazines (5b-i) afforded, regioselectively, 1-substituted ethyl 1H-pyrazole- 5-carboxylates 9a-f and diethyl 1H-pyrazole-3, 4-dicarboxylates, 11a-i, respectively. Upon treatment of 3 with pyridazinylhydrazines 5d-f, the stable intermediates, 1-substituted ethyl ...