4-Methylmorpholine → (2R)-({[4-((2R,3R)-1-(4-Fluorophenyl)-3-{[2-(4-fluorophenyl)-2-oxoethyl]thio}-4-oxoazetidin-2-yl)phenoxy]acetyl)amino)(phenyl)acetic acid

Participants

Reaction Steps

[4-((2R,3R)-1-(4-Fluorophenyl)-3-{[2-(4-fluorophenyl)-2-oxoethyl]thio}-4-oxoazetidin-2-yl)phenoxy]acetic acid (0.40 g, 0.827 mmol) was dissolved in CH2Cl2 (40 ml) and tert-butyl (2R)-amino(phenyl)acetate (0.206 g, 0.993 mmol) and N-methylmorpholine (0.251 g, 2.48 mmol) were added. After 10 minutes, TBTU (0.345 g, 1.076 mmol) was added. The reaction was stirred overnight. The resulting tert-butyl ester was concentrated and purified on silica gel (eluted with EtOAc/CH2Cl2 25/75). The pure fractions were collected and concentrated. CH2Cl2 (25 ml) and TFA (3 ml) were added. The mixture was stirred for 5 days and the solvent was removed under reduced pressure. The residue was purified by preparative HPLC using a gradient of 20-70% CH3CN in 0.1M NH4OAc buffer. Freeze-drying of the pure fractions gave the title compound as a colourless solid. M/z: 615.50 (M−1). 1H NMR [(CD3)2SO), 400 MHz] δ 4.35 (d, 1H), 4.36 (d, 1H), 4.40 (d, 1H), 4.53 (d, 1H), 4.58 (d, 1H), 4.94 (d, 1H), 5.19 (d, 1H), 6.97-7.40 (m, 15H), 8.02-8.06 (m, 2H), 8.26-8.32 (m, 1H).

Provenance & Evidence