4-Amino-2-trifluoromethylbenzonitrile, (2.23 g, 12 mmol) was added portionwise over15 minutes into the well-stirred heterogeneous mixture of thiophosgene (1 ml, 13 mmol) in water (22 ml) at room temperature. Stirring was continued for an additional 1 h. The reaction medium was extracted with chloroform (3 x 15 ml). The combined organic phase was dried over MgSO4 and evaporated to dryness under reduced pressure to yield desired product, 4-isothiocyanato-2-trifluoromethylbenzonitrile, (Ia), as brownish solid and was used as such for the next step (2.72 g, 11.9 mmol, 99%).
