Trifluoroacetic acid → N-{[4-((2R,3R)-1-(4-Fluorophenyl)-3-{[2-(4-fluorophenyl)-2-oxoethyl]thio}-4-oxoazetidin-2-yl)phenoxy]acetyl}-L-alanine

Participants

Reaction Steps

A solution of [4-((2R,3R)-1-(4-fluorophenyl)-3-{[2-(4-fluorophenyl)-2-oxoethyl]thio}-4-oxoazetidin-2-yl)phenoxy]acetic acid (0.020 g, 0.041 mmol), L-Alanine tert-butyl ester hydrochloride (0.009 g, 0.050 mmol) and N-Methylmorpholine (0.018 ml, 0.163 mmol) in DCM (4 ml) was stirred for 5 min. TBTU (0.017 g, 0.053 mmol) was added. The formation of the ester was confirmed after 3 h. M/z: 611.1. TFA (3 ml) was added. After 2 h, the mixture was diluted with toluene (2 ml) and the solvent was removed under reduced pressure. The residue was purified by preparative HPLC, using a gradient of 20-50% MeCN in 0.1M ammonium acetate buffer as eluent. After freeze-drying, 0.023 g (>98%) of the title product was obtained as a white solid. M/z: 555.1. 1H NMR (DMSO, 400 MHz): δ 1.17 (d, 3H), 3.73-3.82 (m, 1H), 4.33 (d, 1H), 4.35 (ABq, 2H), 4.43 (s, 2H), 5.15 (d, 1H), 6.92-7.98 (m, 2H), 7.10-7.24 (m, 4H), 7.29-7.39 (m, 4H), 7.84 (d, 1H), 7.97-8.04 (m, 2H).

Provenance & Evidence