General procedure for the synthesis of tert-butyl (4-(bromomethyl)thiazol-2-yl)carbamate from tert-butyl (4-hydroxymethylthiazol-2-yl)carbamate: to a stirred solution of tert-butyl (4-hydroxymethylthiazol-2-yl)carbamate (115 mg, 0.50 mmol, 1.0 eq.) in dichloromethane (5 mL) at -78 °C was added sequentially triphenylphosphine ( 135 mg, 0.51 mmol, 1.05 equiv) and N-bromosuccinimide (89 mg, 0.50 mmol, 1.0 equiv). After 15 min of reaction, the reaction mixture was quenched with water (2.5 mL) and slowly warmed to 25 °C. The organic and aqueous phases were separated and the aqueous phase was extracted with ethyl acetate (3 x 5 mL). The organic layers were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was purified by fast column chromatography (silica gel, 20% ethyl acetate/hexane) to afford tert-butyl (4-(bromomethyl)thiazol-2-yl)carbamate (104 mg, 0.35 mmol, 71%) as a colorless oil of the target compound (104 mg, 0.35 mmol, 71%). rf = 0.31 (silica gel, 20% ethyl acetate/hexane); FT-IR (neat) νmax 3164, 3056, 2978, 2933, 2803, 1713, 1553, 1478, 1454, 1432, 1393, 1368, 1332, 1289, 1243, 1215, 1151, 1068, 1033, 977, 910, 865, 791, 763, 701, 655 cm-1; 1H NMR ( 600 MHz, CDCl3) δ 10.08 (br s, 1H), 6.88 (s, 1H), 4.54 (s, 2H), 1.56 (s, 9H) ppm; 13C NMR (151 MHz, CDCl3) δ 161.4, 152.6, 146.8, 111.6, 83.2, 28.4, 27.8 ppm; HRMS (ESI) calculated value [M + H]+ 292.9954, measured value 292.9950.
