Synthesis of chromene-3-carbonitrile and pyrano[2,3-d]pyrimidines, starting from cyclic active methylene compounds in the presence of novel deep eutectic solvents as promoter

A simple and efficient protocol with environmental, has been developed for the One-Pot , multicomponent synthesis of fused six membered highly saturated chromene and pyrano[2,3-d]pyrimidines derivatives. These compounds have shown diverse medicinally [1] important effects such as anti-coagulant [2], anti-espasmodic [3], anti-bacterial[4], anti-cancer [5], The use of deep eutectic solvents for the preparation of organic molecules has been emerged as a vital and progressive area of research in recent years [6]. In the recent work, the condensation of various aldehydes, dimedone and mlononitrile in the ratio of 1: 1: 1.2 mmol respectively in the presence of three different deep eutectic solvents is reported. The eutectic solvents applied in this protocol include Choline chloride:urea (1:2), Choline chloride:L-proline (1:1) and Choline chloride:Glucose (1:1). The reactions were well performed at ambient temperatures (30-40oC) and the 2-amino-7,7-dimethyl-8-oxo-4-phenyl-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile and pyrano[2,3-d]pyrimidine-3-carbonitrile products were easily separated from eutectic solvent by dissolving the reaction mixture in water and vacuum filtration. Relatively short reaction times, no need to extra harmful organic solvent, high yields and simple work-up procedure were among the other advantages of the present protocol.