4-Methylmorpholine → n-{[4-((2r,3r)-1-(4-Chlorophenyl)-3-{[2-(4-chlorophenyl)-2-hydroxyethyl]thio}-4-oxoazetidin-2-yl)phenoxy]acetyl}glycyl-3-methyl-d-valine

Participants

Reaction Steps

TBTU (0.020 g, 0.063 mmol) was added to a solution of N-{[4-((2R,3R)-1-(4-chlorophenyl)-3-{[2-(4-chlorophenyl)-2-oxoethyl]thio}-4-oxoazetidin-2-yl)phenoxy]acetyl}glycine (0.030 g, 0.052 mmol) and N-methylmorpholine (0.016 g, 0.157 mmol) in CH2Cl2 (5 ml) at 30° C. After 30 minutes, D-tert-leucine (0.008 g, 0.063 mmol) was added and the mixture was stirred for 30 minutes. The reaction mixture was concentrated. Toluene (2 ml) was added and evaporated. MeOH (3 ml) and sodium borohydride (0.020 g, 0.523 mmol) were added. Full conversion to the corresponding alcohol was obtained after 5 minutes. The reaction was quenched by the addition of 0.1M NH4OAc (1 ml) buffer and the mixture was concentrated. The residue was purified by preparative HPLC using an eluent of 0-50% CH3CN in 0.1M NH4OAc buffer. Freeze-drying of the pure fractions afforded the title compound (0.021 g, 58%) as a colourless solid. 1H NMR [(CD3)2SO), 400 MHz] δ0.85 (s, 9H), 2.82-2.98 (m, 2H), 3.75-3.81 (m, 2H), 3.91-3.96 (m, 1H), 4.29-4.37 (m, 1H), 4.52 (s, 2H), 4.70-4.78 (m, 1H), 5.01-5.06 (m, 1H), 6.97-6.99 (m, 2H), 7.19-7.21 (m, 2H), 7.32-7.36 (m, 8H), 7.52-7.63 (m, 1H), 8.27-8.32 (m, 1H).

Provenance & Evidence