Theophylline as the catalyst for the diastereoselective synthesis of trans-1,2-dihydrobenzo[a]furo[2,3-c]phenazines in water

An efficient, convenient and environmentally benign procedure for the synthesis of novel 1,2-dihydrobenzo[a]furo[2,3-c]phenazine derivatives with high diastereoselectivity has been developed by a domino four-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines, aromatic aldehyde and pyridinium ylide in the presence of a catalytic amount of theophylline as an expedient, eco-friendly and reusable solid base catalyst in water. This one-pot process produces biologically and pharmacologically significant heterocycles with the formation of five new bonds (two C-C, two C = N and one C-O) and two new rings in a single operation and this effective green process provides considerable advantages such as: operational simplicity, short reaction time, high yields, reusability of catalyst, absence of any tedious workup or purification and avoiding hazardous reagents/solvents.