Acetone → {4-[(2r,3r)-3-{[2-(4-Ethoxyphenyl)-2-oxoethyl]thio}-1-(4-fluorophenyl)-4-oxoazetidin-2-yl]phenoxy}acetic acid

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Reaction Steps

tert-Butyl (4-{(2R,3R)-1-(4-fluorophenyl)-3-[(3-nitropyridin-2-yl)dithio]-4-oxoazetidin-2-yl}phenoxy)acetate (0.25 g, 0.45 mmol) was dissolved in acetone (10 ml) at room temperature. Water (2.5 ml) and triphenyl phosphine (0.12 g, 0.45 mmol) were added. The mixture was stirred at room temperature for 15 minutes and then concentrated under reduced pressure to afford the crude thiol as a brown oil. This crude thiol was immediately dissolved in CH2Cl2 (10 ml) and (2-bromo-3′-ethoxy acetophenone (0.22 g, 0.90 mmol) was added, followed by Et3N (0.13 ml, 0.90 mmol). The mixture was stirred at room temperature for 19 hours, concentrated under reduced pressure and purified by flash-chromatography (Hex:EtOAc 3:1). This afforded a colourless oil that was dissolved in formic acid (10 ml) and stirred at ambient temperature for 18 hours. Concentration under reduced pressure and purification by flash-chromatography (hex:acetone:formic acid 60:40:0.1) afforded 0.13 g (57%) of the desired product as a pale yellow solid.

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