Mesoporous alumina sulphuric acid: A novel and efficient catalyst for on-water synthesis of functionalized 1,4-dihydropyridine derivatives via β-enaminones

A simple, efficient and environmentally benign on-water protocol for the synthesis of novel 1,4-dihydropyridine derivatives via pseudo four component addition and cyclization sequence using mesoporous alumina sulphuric acid as a recyclable and heterogeneous catalyst, has been described. The catalyst showed excellent catalytic activity giving products in high yields and could be reused for seven successive catalytic cycles. The catalyst was characterized by FT-IR, XRD, FE-SEM, EDX and TG analyses. The mesoporosity of alumina was determined by BET and TEM analyses. (C) 2014 Elsevier B.V. All rights reserved.