Methyl iodide → 5-{[tert-butyl(dimethyl)silyl]oxy}-3-methyl-1,3-benzoxazol-2(3H)-one

Participants

Reaction Conditions

Reaction Steps

To a cooled (0° C.) solution of 5-{[tert-butyl(dimethyl)silyl]oxy}-1,3-benzoxazol-2(3H)-one (1.45 g, 5.4 mmol) in anhydrous N,N-dimethylformamide (10 mL) was added sodium hydride (0.26 g, 60% dispersion in mineral oil, 6.6 mmol). The reaction mixture was stirred at 0° C. for 15 min followed by the addition of iodomethane (1.0 mL, 16 mmol). The reaction mixture was stirred at ambient temperature for 16 h and diluted with water (20 mL) and ethyl acetate (20 mL). The phases were separated and the aqueous phase was extracted with ethyl acetate (2×20 mL). The combined organic solution was washed with water (5×20 mL) and brine (2×20 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product was purified by column chromatography with ethyl acetate in hexanes (0 to 25% gradient) to afford 5-{[tert-butyl(dimethyl)silyl]oxy}-3-methyl-1,3-benzoxazol-2(3H)-one (1.26 g, 83%) as a pale yellow solid: 1H NMR (300 MHz, CDCl3) δ7.02 (d, J=8.6 Hz, 1H), 6.55 (dd, J=8.6, 2.4 Hz, 1H), 6.44 (d, J=2.4 Hz, 1H), 3.35 (s, 3H), 0.99 (s, 9H), 0.20 (s, 6H).

Provenance & Evidence