Silica-ZnCl₂: An Efficient Catalyst for the Synthesis of 4-Methylcoumarins

Abstract

Silica-ZnCl2 has been found to be an efficient and eco-friendly catalyst for the synthesis of substituted 4-methylcoumarins from ethyl acetoacetate and substituted phenols under “neat” conditions in an oil bath at 80°C. The experimental procedure is simple, includes shorter reaction times (15–65 min), compatible with sensitive functional groups, and results in excellent yield of the products.

An SiO2/ZnBr2mediated expeditious approach to 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one derivatives in water under microwave irradiation

“…5). Further there is no weight loss upto 800 C. Therefore it can be concluded that physiosorbed and chemisorbed ZnBr 2 on silica surfaces is stable upto 800 C. 37…”