General procedure for the synthesis of 2-methylthio-4,6-dichloropyrimidine-5-oxime from 2-methylthio-4,6-dichloro-5-cyanopyrimidine: To 4,6-dichloro-2-(methylthio)-5-pyrimidine carboxaldehyde oxime (2.38 g, 10 mmol) was slowly added dichlorosulfoxide (SOCl2, 21.8 mL, 0.30 mol) at room temperature. Subsequently, the reaction mixture was heated to 75 °C with continuous stirring for about 3 hours. After completion of the reaction, the reaction solution was concentrated under vacuum. The residual dichlorosulfoxide was removed by addition of toluene (5 mL) and evaporated under vacuum. The resulting solid was washed with ethanol/water (10 mL, 1:1 v/v) to afford 4,6-dichloro-2-(methylthio)-5-pyrimidinecarbonitrile (2.04 g, 93% yield). The product was analyzed by LC-MS showing m/z 220 ([M+H]+) with a retention time of 1.99 min; 1H-NMR (CDCl3) δ 2.64 (3H, s).
