Pyrrolidine-based acidic ionic liquid: An efficient and recyclable catalyst for the synthesis of 5-arylidene barbituric acid derivatives in aqueous media

Since many years, acid-catalyzed organic transformations have been used extensively to produce numerous organic products. In such transformations, mineral acids have mainly been employed. These acids are highly corrosive, toxic, and are responsible for environmental hazards. In order to solve these problems the subject of ionic liquids with acidic properties as potential green alternatives has been attended by organic researchers.1,2 Barbituric acids and their derivatives have been widely used as sedative, hypnotic, anesthetic, anticonvulsant, antiosteoporosis, as well as antitumor agents. Arylidene barbituric acids as well as their 2-thio analogues are useful intermediates in the synthesis of important heterocyclic compounds.3As a part of our continuing interest on designing environmentally benign methods for various chemical transformations, 4,5 herein we have described an efficient route for the synthesis of 5-arylidene barbituric acid derivatives using pyrrolidine-based acidic ionic liquid as an affordable and recyclable catalyst (Figure 1). The present protocol show some advantages such as high yields, reduced reaction times, no by-product, clean and simple work-up.

Keywords:

Pyrrolidine , Brönsted acidic ionic-liquid , Barbituric acid , Aqueous media , Green organic synthesis.