A cascade reaction for the new and direct synthesis of indolofuroquinoxalines

Abstract

The 7H-indolo[3′,2′:4,5]furo[2,3-b]quinoxaline derivatives are synthesized directly from methyl 2-(2-chloro-1H-indol-3-yl)-2-oxoacetate or its N-alkyl derivatives under neutral or mildly acidic conditions. This new one-pot methodology was found to be general and greener as it avoids the use of environmentally harmful POCl₃ and strong alkali required for the previously reported method. It is also amenable for scale-up.