4-Methylmorpholine → N-({4-[(2R,3R)-3-{[2-(1,3-benzodioxol-5-yl)-2-hydroxyethyl]thio}-1-(4-fluorophenyl)-4-oxoazetidin-2-yl]phenoxy}acetyl)glycine

Participants

Reaction Steps

To a stirred solution of {4-[(2R,3R)-3-{[2-(1,3-benzodioxol-5-yl)-2-oxoethyl]thio}-1-(4-fluorophenyl)-4-oxoazetidin-2-yl]phenoxy}acetic acid (Method 7) 208 mg, 0.41 mmol) in DCM (16 ml) were added N-methylmorpholine (130 μl, 1.18 mmol), tert-butyl glycinate hydrochloride (102.3 mg, 0.61 mmol) and TBTU (180.8 mg, 0.56 mmol). The reaction mixture was stirred at ambient temperature overnight. The formation of the intermediate tert-butyl N-({4-[(2R,3R)-3-{[2-(1,3-benzodioxol-5-yl)-2-oxoethyl]thio}-1-(4-fluorophenyl)-4-oxoazetidin-2-yl]phenoxy}acetyl)glycinate confirmed. M/z: 623.88 (M+1) and 621.84 (M−1). The solvent was removed under reduced pressure and the residue was passed through a short silica gel pad and eluted with DCM:EtOAc 8:2. The collected fractions were concentrated under reduced pressure. The crude oil (0.818 mg) was dissolved in DCM (6 ml) and TFA (4 ml) was added and the mixture was stirred for 1 hour. The formation of the ketone of the title compound was confirmed. M/z: 567.74 (M+1) and 565.79 (M−1). The solvent was co-evaporated with toluene under reduced pressure. The residue was dissolved in methanol (8 ml) and sodium borohydride (128.6 mg, 3.40 mmol) and the mixture was stirred for 40 minutes Ammonium acetate (200 mg) was added and the solvent was removed under reduced pressure. The residue was purified with preparative HPLC on a C8 column, UV 240/260 nm. A gradient from 20 to 50% MeCN in 0.1M NH4OAc buffer was used as eluent. The pure fractions were collected and the MeCN was removed under reduced pressure. The remaining water solution was acidified to pH 1 with HCl (1M) and extracted with DCM. The organic phase was passed through a phase separator and concentrated under reduced pressure. The residue was dissolved in MeCN and water. After lyophilisation, the title compound was obtained. H-NMR (400 MHz, DMSO-d6): 2.78-2.89 (m, 2H), 3.76 (d, 2H), 4.22-4.25 (m, 1H), 4.49 (s, 2H), 4.55-4.64 (m, 1H), 5.01 (d, 0.5H), 5.03 (d, 0.5H), 5.52 (bs, 1H), 5.90-5.94 (m, 2H), 6.70-6.79 (m, 2H), 6.82 (s, 1H), 6.96 (d, 2H), 7.08-7.16 (m, 2H), 7.18-7.24 (m, 2H), 7.34 (d, 2H), 8.34 (t, 1H). M/z: 567.52 (M−1).

Provenance & Evidence