3973-08-8

75-65-0

1235406-42-4

Under nitrogen protection, 5.80 mL (41.84 mmol) of triethylamine and 9.10 mL (42.19 mmol) of azido azide phosphate were sequentially added to a solution of 4.85 g (37.55 mmol) of thiazole-4-carboxylic acid dissolved in 180 mL of tert-butanol and the reaction mixture was cooled in an ice bath. Subsequently, the reaction system was heated to reflux for 16 hours. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was dissolved in dichloromethane and washed twice sequentially with water and saturated sodium chloride solution. The organic phase was dried over anhydrous sodium sulfate and concentrated. The resulting crude product was purified by silica gel column chromatography (eluent: cyclohexane/ethyl acetate, 1:1, v/v) to afford 7.07 g (35.30 mmol, 94% yield) of N-Boc-4-aminothiazole as beige crystals.ESI-MS: m/e 201 ([M + H]+).