Regioselective Synthesis of 1,6‐Dihydropyrrolo[2,3‐g]indazole Derivatives via Three‐Component Domino Reaction

Abstract

A series of 1,6-dihydropyrrolo[2,3-g]indazole derivatives have been obtained by a three-component domino reaction of 1H-indazol-6-amine, arylglyoxal monohydrates, and cyclic 1,3-dicarbonyl compounds in ethanol medium at 60°C catalyzed by acetic acid. The notable features of this synthesis are excellent regioselectivity, operational simplicity, relative mild reaction conditions, and good yields.

Synthesis and activities of tricyclic pyrido[3,4-g]quinazolines, pyrazolo[3,4-g]quinoxalines and pyrroloindazole regioisomers

“…nucleus could also be achieved by reaction of 6-aminoindazoles 83 with arylglyoxal hydrates and cyclic 1,3dicarbonyl compounds to give 86 41 , or by condensation of 83 or 87 with benzoin, to give 7,8-diphenyl derivatives 85 and 86 42 , (Scheme 15). The pyrrolo [3,2-f]indazole scaffold could also be formed using this reaction, starting from 6-amino-7-chloroindazole.…”

“…40 Three-component reaction using 6aminoindazole 83, arylglyoxal hydrates and cyclic 1,3-dicarbonyl compounds. 41 Condensation of indazoles 83 and 87 with benzoin. 42 In 2011, we reported the preparation of diversely substituted pyrrolo[2,3-g]indazoles.…”