Simple microwave-assisted method for the synthesis of primary thioamides from nitriles

Primary thioamides are prepared in excellent yield from the corresponding nitrile by treatment with ammonium sulfide in methanol. at room temperature for electron-deficient aromatic nitriles or under microwave irradiation at 80 degreesC or 130 degreesC in 15-30 minutes for other aromatic and aliphatic nitriles. This procedure avoids the use of gaseous H,S under high pressure, proceeds in the absence of base and provides thioamides usually without the need for chromatographic purification.