An unusual synthesis of 3-(2-(arylamino)thiazol-4-yl)-2H-chromen-2-ones from ethyl 2-(chloromethyl)-2-hydroxy-2H-chromene-3-carboxylate via benzopyran ring opening.

An unusual and unexpected synthesis of 3-(2-(arylamino)thiazol-4-yl)-2H-chromen-2-ones has been observed by the reaction of ethyl 2-(chloromethyl)-2-hydroxy-2H-chromene-3-carboxylate with various arylthioureas in ethanol under mild reaction conditions with excellent yields. The ambiguity in the structure of the obtained products has been solved by recording its single-crystal X-ray analysis. This protocol has been found to be a novel approach for the preparation of title compounds via benzopyran ring opening.

A Review on Pharmacological Properties of Coumarins.

The coumarin (benzopyran-2-one, or chromen-2-one) ring system, present in many natural products, displays diverse pharmacological properties. It has attracted the attention of chemists and medicinal chemists for decades. Many molecules based on the coumarin ring system have been described utilizing innovative synthetic methods.