A clean, simple and efficient synthesis of 1-[N-(5-hydroxybenzo[d][1,3]dioxol-4- yl] (aryl)methyl)acetamides via chlorosulfonic acid as catalyst: A green protocol

We reported a green, simple and efficient method for the synthesis of 1-[N-(5-hydroxybenzo[d][1,3]dioxol-4- yl](aryl)methyl)acetamides employing a multi-component and one-pot condensation reaction of aryl aldehydes, benzo[1,3]dioxol-5-ol, and acetonitrile in the presence of catalytic amounts of chlorosulfonic acid at ambient temperature. To a magnetically stirred solution of benzo[1,3]dioxol-5-ol (2 mmol) and aldehyde in acetonitrile was added chlorosulfonic acid at room temperature. The reaction mixture was then stirred for 1 h. The mixture was poured into 50 mL ice-water. The solid product was filtered, washed with ice-water to give the pure product. The structures of compounds were deduced from elemental analysis and their IR, 1H NMR, 13C NMR spectra. This new protocol offers advantages such as mild reaction conditions, short reaction time, easy work-up, and use of an inexpensive and non-toxic catalyst, high yields of biological active products and does not involve any hazardous solvent. Therefore, this procedure could be classified as green chemistry.