Graphene oxide as a catalyst for one-pot sequential aldol coupling/aza-Michael addition of amines to chalcones through in situ generation of Michael acceptors under neat conditions

Graphene oxide (GO) in conjunction with tetra n-butyl ammonium bromide (TBAB) was found to function as an efficient catalyst for one-pot sequential aldol coupling/aza-Michael addition of amines to chalcones in a single reaction vessel. Benzaldehydes and acetophenone were coupled in situ to produce their corresponding chalcones which underwent a subsequent aza-Michael addition under solvent-free condition. This procedure avoids the use of precious metals and the heterogeneous nature of the GO simplifies purification and isolation of the products by simple filtration of the catalyst. (C) 2019 Elsevier Ltd. All rights reserved.