One-Pot Condensation Approach for the Synthesis of Tetrahydrobenzo [b] pyran Derivatives Utilizing Salicylic Acid as an Efficient and Ecofriendly Catalyst

In recent years, the synthesis of pyran derivatives, especially tetrahydrobenzo[b]pyrans, hasreceived an increasing interest because of attractive pharmacological and biological properties[1]. These compounds are also used in the industry as optical brighteners, laser dyes, pigments,cosmetics and potent biodegradable agrochemicals [1-3]. In a continuation of our endeavorstowards the development of new catalytic protocol, we wish to report an efficientone-pot, three-component strategy for the rapid synthesis of dimedone (1 mmol), malononitrile(1 mmol), aldehyde (1 mmol) in the presence of a catalytic amount (20 mol %) of salicylicacid in EtOH/H2O at 70 °C. The advantages of this protocol are higher product yields inshorter reaction times, easy work-up, and available of the catalyst (Fig .1)