Reactivity of 1,1-disubstituted indazol-3-ylio oxides: synthesis of some substituted indazolols and indazolinones

Abstract

Some aspects of the reactivity of 1,1-disubstituted indazol-3-ylio oxides (indazolol-derived aminimides) have been studied. Treatment of these compounds with hydrochloric acid gave the corresponding indazolium salts which, through elimination of an alkyl chloride, afforded 1-substituted indazol3-ols. Treatment with alkoxides yielded N′,N′-disubstituted 2-alkoxybenzohydrazides or 1-substituted indazolols (aryl or alkyl ether elimination products, respectively). The thermal rearrangements of indazolylio oxides gave 1-substituted indazolols. 1,2-disubstituted indazolinones and 3-alkoxy-1alkylindazoles depending on the substituents. The direct cyclization of N′,N′-disubstituted 2-chloro5-nitrobenzohydrazides to indazole derivatives as well as the reactivity of some of the above mentioned compounds are also reported.