ChemInform Abstract: A New Method for Introducing the 2,2-Dichloroethyl Group at the 3 Position of the 2-Quinolone System, and the Synthesis of Dictamnine

A novel method is described for the introducing the 2, 2-dichloroethyl group at the 2-quinolone ring. The method from 4-substituted 2-quinolone consists of 1) photoaddition of the quinolone to 1, 1-dichloroethylene, 2) base treatment of the cross adduct giving a bicyclobutane, and 3) conversion of the latter to the final product with hydrogen chloride. By applying this reaction to 4-methoxy-2-quinolone, a short-step synthesis of dictamnine is accomplished.