ChemInform Abstract: 5‐Diazo‐6,6‐dimethyl‐4‐oxo‐4,5,6,7‐tetrahydroindazoles in [3 + 2] Cycloaddition Reactions.

Abstract

Pyrazole derivatives R 0180 5-Diazo-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazoles in [3 + 2] Cycloaddition Reactions. -Employing classical methods diazoindazoles (I) react with maleic anhydride (II) to the spiroindazoles (III). Heating of the pyrazolines (IIIa) and (IIIb) at the melting point gives rise to the release of nitrogen and transformation into spirobicyclohexaneindazoles (IV). Carboxylic acids (V) and (VII) are formed by treatment of anhydrides (IV) with either NaOH or benzylamine. The reaction of diazoindazoles (Ib), (Id) and (X) with dimethyl acetylenedicarboxylate (VIII) yields the spiropyrazoleindazoles (IX) and (XI), respectively. -(STRAKOVA, I.; STRAKOVS*, A.; PETROVA, M.; BELYAKOV, S.; Chem. Heterocycl. Compd. (N. Y.) 43 (2007) 12, 1512-1518; Riga Tech. Univ., Riga 1048, Latvia; Eng.) -H. Hoennerscheid 38-113