Basic $Al_2O_3$ as a recyclable reagent for the protection of carbonyl groups with phenylhydrazine derivaties and semicarbazides

Abstract

Basic alumina is employed as an inorganic basic solid catalyst for the clean and less hazardous protection of carbonyl compounds, such as phenylhydrazones, 2,4-dinitrophenylhydrazones, semicarbazones,and thiosemicarbazones, under solvent-free conditions. The reactions proceed smoothly and require a short reaction time with good to excellent yields, and the alumina used can be recycled.