4-Methylmorpholine → N-([4-((2R,3R)-1-(4-Fluorophenyl)-3-{[2-(4-fluorophenyl)-2-oxoethyl]thio}-4-oxoazetidin-2-yl)phenoxy]acetyl}-D-valine

Participants

Reaction Steps

[4-((2R,3R)-1-(4-Fluorophenyl)-3-{[2-(4-fluorophenyl)-2-oxoethyl]thio}-4-oxoazetidin-2-yl)phenoxy]acetic acid, (50.0 mg, 0.10 mmol) was dissolved in DCM (2 ml). tert-Butyl D-valinate hydrochloride (28.4 mg, 0.14 mmol) and N-methylmorpholine (3.0 μl, 0.31 mmol) were added. After 5 minutes, TBTU (43.7 mg, 0.14 mmol) was added and the mixture was stirred overnight. The intermediate tert-butylester of the title compound was confirmed. M/z: 637.1 (M−H). The solvent was removed under reduced pressure. The yellow residue was dissolved in formic acid (1.5 ml) and heated at 50° C. for 5 h. The solvent was evaporated and the residue was purified by preparative HPLC on a C8 column. A gradient from 20 to 50% MeCN in 0.1 M ammonium acetate buffer was used as eluent. After lyophilisation, the title compound was obtained as a white solid (30.5 mg, 51%). 1H-NMR (400 MHz, DMS-d6): 0.74 (t, 6H), 1.98-2.07 (m, 1H), 3.84 (brs, 1H), 4.32 (d, 1H), 4.35 (s, 1H), 4.36 (s, 1H), 4.50 (brs, 2H), 5.16 (d, 1H), 6.96 (d, 2H), 7.10-7.17 (m, 2H), 7.19-7.24 (m, 2H), 7.31-7.38 (m, 4H), 7.66 (brs, 1H), 7.99-8.04 (m, 2H). M/z: 583.0 (M+H) and 581.0 (M−H).

Provenance & Evidence