Cyanamide → Methyl 4-amino-2-benzamidothiazole-5-carboxylate

Participants

Reaction Steps

To a solution of benzoyl isothiocyanate (4.00 mL, 29.70 mmol) and cyanamide (1.37 g, 32.50 mmol) in tetrahydrofuran (80 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (4.90 mL, 32.80 mmol) at 0° C. The resulting reaction mixture was stirred at ambient temperature for 3 hours. Methyl bromoacetate (3.00 mL, 32.00 mmol) was added to the reaction mixture. The reaction mixture was kept stirring for 1 hour at ambient temperature. Another portion of 1,8-diazabicyclo[5.4.0]undec-7-ene (4.90 mL, 32.80 mmol) was added. The reaction mixture was stirred at ambient temperature for another 16 hours. The solvent was removed in vacuo, and the residue was dissolved in ethyl acetate (200 mL), washed with brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated and the residue was purified by column chromatography to give methyl 4-amino-2-benzamidothiazole-5-carboxylate (0.16 g, 2%); 1H NMR (CDCl3, 300 MHz) δ 7.60-7.41 (m, 5H), 5.43 (s, 2H), 3.95 (s, 3H); MS (ES+) m/z 277.3 (M+1).

Provenance & Evidence