Vilsmeier-Haack Reaction with 2,3,3-Trimethyl-3H-benzo[g]indole and Its Conversion into 2-(1-aryl-1H-pyrazol-4-yl)-3,3-dimethyl-3H-benzo[g]indoles

Abstract

Vilsmeier-Haack reaction of 2,3,3-trimethyl-3<em>H</em>-benzo[<em>g</em>]indole, then aqueous basic work-up, leads to benzo[g]indol-2-ylidene- malondialdehydes. These react with various arylhydrazines and quinolin-2-ylhydrazine to form 3,3-dimethyl-2-(1-aryl-1<em>H</em>-pyrazol-4-yl)- 3<em>H</em>-benzo[<em>g</em>]indoles in good yields.