To a solution of [(3-benzyloxy-phenyl)-(3-chloro-pyrazin-2-yl)-methyl]-thiocarbamic acid S-methyl ester (200 mg, 0.0005 mol) in MeCN (10 mL) and DMF (0.12 mL, 0.0015 mol) was added POCl3 (0.14 mL, 0.0015 mol); the resulting mixture was stirred at 55° C. overnight. The mixture was quenched with 2N NH3/iPrOH, then diluted with EtOAc, washed with brine and dried over anhydrous sodium sulfate. The residue was purified by silica gel chromatography (Hex.: EtOAc=80:20→70:30) to give a yellow solid. 1H-NMR (CDCl3) confirmed a mixture of the desired product and starting material in ca. 1:1 ratio, which was taken on to next step.
