Synthesis of Tetrahydrobenzo[b]Pyran Derivatives Catalysed by Aliquat®336 in Water Under Microwave Irradiation

Abstract

A series of 4 H-5,6,7,8-tetrahydrobenzo[ b]pyran derivatives has been synthesised in excellent yield in a single pot using trioctylmethylammonium chloride (Aliquat®336) as phase-transfer catalyst in water under microwave irradiation. This method provides a clean access to the desired products. The structures of the products were confirmed by IR, 1H NMR, 13C NMR in all cases and HRMS in several cases, and supported by single crystal X-ray diffraction analysis of 2-amino-4-(3-benzyloxy-4-methoxyphenyl)-3-cyano-7,7-dimethyl-5-oxo-4 H-5,6,7,8-tetrahydrobenzo[ b]pyran and 2-amino-3-cyano-4-(3-iodo-4-hydroxy-5-methoxyphenyl)-7,7-dimethyl-5-oxo-4 H-5,6,7,8-tetrahydrobenzo[ b] pyran.