A direct synthesis of β-carbolines via a three-step one-pot domino approach with a bifunctional Pd/C/K-10 catalyst

A rapid, microwave-assisted synthesis of beta-carbolines via a Successive condensation/cyclization/dehydrogenation approach is described. This methodology involves the coupling of various tryptamines with aromatic aldehydes/glyoxals. The product imine undergoes a Pictet-Spengler cyclization followed by a final dehydrogenation to yield beta-carbolines in a three-step domino reaction. The use of the bifunctional catalyst Pd/C/K-10 combined with microwave irradiation enabled the synthesis of beta-carbolines in short reaction times and in good to excellent yields. (C) 2009 Elsevier Ltd. All rights reserved.