Present study describes a novel, one-pot synthesis of amides of carboxylic acids that involves sequential addition of diphenyl carbonate, an amine catalyst to a carboxylic acid at 60-80 °C to generate a carbonic anhydride (in-situ) that rearranges to a phenyl ester, and is followed by addition of another amine to yield an amide in good to excellent isolated yield. This methodology has successfully been applied to the synthesis of drug molecules (acetaminophen, moclobemide, vorinostat) and intermediates of glipizide, glibenclamide, gedatolisib and enzalutamide drug molecule.