A broad scope of aromatic and aliphatic primary amides were converted to their corresponding nitriles in high yields by using polymethylhydrosiloxane (PMHS) in the presence of catalytic amounts of ZnBr₂ and propylphosphonic anhydride (T3P). As an example of dehydration reaction promoted by anhydrides, ZnBr₂ and T3P cooperatively activate the amide substrate and the silane to allow the desired dehydration to occur smoothly under mild conditions. Moreover, this method is suitable for the condensation reaction of carboxylic acids with amines to give the corresponding amide products, including a key intermediate of cinacalcet.