Synthesis of pyranopyrazoles, benzopyrans, amino-2-chromenes and dihydropyrano[c]chromenes using ionic liquid with dual Br?nsted acidic and Lewis basic sites

Article abstract of DOI:10.1515/chempap-2015-0066

An efficient ionic liquid with both Br?nsted acidic and Lewis basic sites, namely 1,4-dimethyl-1- (4-sulphobutyl)piperazinium hydrogen sulphate (IL1), was synthesised and characterised. IL1 is a "green", homogeneous and reusable catalyst for: i) the synth