A one-pot, four-component synthesis of α-carboline derivatives

A one-pot method for the efficient and simple synthesis of novel 1H-indolo[2,3-b]pyrazolo(4,3-e)pyridines via a four-component condensation reaction of indolin-2-one, 3-oxo-3-phenylpropanenitrile, and various hydrazines and aldehydes in the ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) is reported. (C) 2009 Elsevier Ltd. All rights reserved.