4-Methylmorpholine → N-([4-((2R,3R)-1-(4-fluorophenyl)-3-{[2-(4-fluorophenyl)-2-hydroxyethyl]thio)-4-oxoazetidin-2-yl)phenoxy]acetyl}-D-valyl-D-lysine

Participants

Reaction Steps

N-{[4-((2R,3R)-1-(4-Fluorophenyl)-3-{[2-(4-fluorophenyl)-2-oxoethyl]thio}-4-oxoazetidin-2-yl)phenoxy]acetyl}-D-valine (14.7, 0.025 mmol), tert-butyl N6-(tert-butoxycarbonyl)-D-lysinate hydrochloride (10.3, 0.03 mmol) and N-methylmorpholine (10 μl, 91 μmol) were dissolved in DCM (1.5 ml). After 5 min, TBTU (9.8 mg, 0.03 mmol) was added and the reaction mixture was stirred overnight. Additional N6-(tert-butoxycarbonyl)-D-lysinate hydrochloride (3.4 mg, 0.01 mmol), N-methylmorpholine (5 μl, 45/μmol) and TBTU (3.3 mg, 0.01 mmol) were added and the mixture was stirred for 2 h. Aqueous KHSO4 (3 ml) was added and the mixture (pH of 3) was extracted with DCM (3×5 ml). The combined organic phases were washed with water (2×5 ml) and dried over Na2SO4. The solvent was removed under reduced pressure. The crude residue (17.1 mg) was dissolved in DCM (1.5 ml) and TFA (1 ml). The solution was stirred for 1.5 h. The solvent was removed under reduced pressure. Toluene was added and evaporated to assist the removal of TFA. The residue was dissolved in methanol (2 ml) and sodium borohydride (11.5 mg, 0.30 mmol) was added. The mixture was for ca 15 minutes. After removal of the solvent under reduced pressure, the residue was purified with preparative HPLC on a C8 column. A gradient from 20% to 50% MeCN in 0.1M ammonium acetate buffer was used as eluent. After lyophilisation, the title compound was obtained as a white solid. (7.8 mg, 43%). 1H-NMR (400 MHz, DMSO-d6): 0.75 (d, 3H), 0.79 (d, 3H), 1.17-1.63 (m, 4H), 1.96-2.06 (m, 1H), 2.61-2.69 (m, 2H), 2.85-2.93 (m, 2H), 3.72-3.80 (m, 1H), 4.12 (t, 1H), 4.27 (s, 0.5H), 4.30 (s, 0.5H), 4.53-5.64 (m, 2H), 4.67-4.76 (m, 1H), 5.01-5.05 (m, 1H), 6.94 (d, 2H), 7.03-7.16 (m, 4H), 7.29-7.39 (m, 4H), 7.50-7.57 (brs, 1H), 8.05 (d, 1H). M/z: 713.1.

Provenance & Evidence