Synthesis of 1-Indolyl-3,5,8-Substituted γ-Carbolines: One Pot Metal-Solvent Free Protocol and Biological Evaluation

Abstract

1,5-Disubstituted indole-2-carboxaldehyde derivatives (1a–h) and glycine alkyl esters (2a–c) are shown to undergo a novel cascade imination-heterocylisation in the presence of organic base DIPEA to provide 1-indolyl 3,5,8-substituted g-carbolines (3aa–ea) in good yields. The g-carbolines are fluorescent and exhibit anticancer activities against cervical, lung, breast, skin and kidney cancers.

Synthesis of 1-indolyl-3,5,8-substituted γ-carbolines: one-pot solvent-free protocol and biological evaluation

“…Recently, we reported the synthesis of substituted pyrrole-2aldehydes to 5-azaindole transformation during a base-catalyzed imination reaction [31]. However, we envisioned that our methodology might be strategically applied towards the synthesis of substituted γ-carbolines as a C-3 nucleophilic attack is more favored in indoles than in pyrroles.…”