Acetic Anhydride → HCID 59643928, compound

Participants

Reaction Steps

(3R,4S)-4-(4-Bromo-2-hydroxyphenyl)-3-[(3S)-3-{[tert-butyl(dimethyl)silyl]oxy}-3-(4-fluorophenyl)propyl]-1-phenylazetidin-2-one (293 mg, 0.50 mmol) was dissolved in anhydrous dichloromethane (3 mL). 4-Dimethylaminopyridine (183 mg, 1.5 mmol) was added followed by acetic anhydride (280 μL, 302 mg, 3.0 mmol). After 1 h the reaction was filtered through a plug of silica gel and eluted with dichloromethane. The solvent was concentrated, azeotroped with toluene and purified by chromatography (40 g silica gel, 1% to 85% ethyl acetate-hexane) to afford 5-bromo-2-{(2S,3R)-3-[(3S)-3-{[tert-butyl(dimethyl)silyl]oxy}-3-(4-fluorophenyl)propyl]-4-oxo-1-phenylazetidin-2-yl}phenyl acetate (245 mg, 78% yield); Rf 0.47 (1:4 ethyl acetate-hexane); 1H NMR (300 MHz, CDCl3) δ 7.38-7.16 (m, 9H), 7.14-6.94 (m, 3H), 4.69 (t, J=5.4 Hz, 1H), 4.64 (d, J=2.3 Hz, 1H), 3.06 (ddd, J=4.7, 2.3, 2.2 Hz, 1H), 2.30 (s, 3H), 1.97-1.78 (m, 4H), 0.89 (s, 9H), 0.032 (s, 3H), −0.14 (s, 3H) ppm; MS [M−OSi(CH3)2C(CH3)3]+ 493.8.

Provenance & Evidence