General procedure for the synthesis of 2-bromothiazole-4-methanol from ethyl 2-bromothiazole-4-carboxylate: In a dry reaction flask, ethyl 2-bromothiazole-4-carboxylate (10.0 g, 42.4 mmol, 1 eq.) was dissolved in tetrahydrofuran (200 mL), and sodium borohydride (4.81 g, 127 mmol, 3 eq.), lithium chloride (5.4 g, 130 mmol, 3 eq.), and water (40 mL) were added in sequence. 130 mmol, 3 equiv) and water (40 mL). The resulting two-phase mixture was stirred vigorously at room temperature for 2 h. The progress of the reaction was monitored by thin layer chromatography (TLC, unfolding agent 20% ethyl acetate/hexane) to confirm complete consumption of the raw materials. Upon completion of the reaction, the reaction was quenched with saturated aqueous ammonium chloride solution (200 mL), diluted with the addition of ethyl acetate (200 mL), and the organic and aqueous layers were separated. The aqueous layer was extracted with ethyl acetate (100 mL), the organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 2-bromothiazole-4-methanol as a yellow semi-solid (7.82 g, 95% yield). The Rf value of the thin-layer chromatography was 0.2 (silica gel plate, unfolding agent was 20% ethyl acetate/hexane); the 1H NMR and 13C NMR spectra of the product were consistent with those reported in the literature (Wipf and Wang, 2007).
