Hydrogen Peroxide → [(R)-1-Methyl-1-(3-oxo-1,5-dihydro-benzo[e][1,3,2]dioxaphosphepin-3-yloxymethyl)-3-(2-pentyl-benzoxazol-5-yl)-propyl]-carbamic acid tert-butyl ester

Participants

Reaction Steps

Under an atmosphere of argon a solution of [(R)-1-Hydroxymethyl-1-methyl-3-(2-pentyl-benzoxazol-5-yl)-propyl]-carbamic acid tert-butyl ester (151 mg, 0.387 mmol) and tetrazole (85 mg, 1.21 mmol) in dry THF (3 ml) was treated with N,N-diethyl-1,5-dihydro-2,4,3-benzo-dioxaphosphepin-3-amine (185 mg, 0.77 mmol) and stirred for 1 hours at RT. After cooling the reaction mixture to 0° C., aqueous hydrogen peroxide (0.4 ml of a 30 w/w % solution) was added and the reaction was allowed to stir for one hour at RT. The reaction mixture was distributed between a 10% aqueous Na2S2O3 solution and AcOEt. The organic layer was dried over MgSO4, concentrated in vacuum and purified over silica gel (eluent (DCM/methanol 30/1). The title compound was obtained as an colorless amorphous solid. 1H-NMR (DMSO-d6) δ: 7.52 (d, J=8.3 Hz; 1H), 7.50-7.40 (m; 5H), 7.15 (dd, J=8.3, 1.5 Hz; 1H), 6.8 (bs; 1H), 5.32-5.26/5.16-5.04 (m; 4H), 4.17/4.06 (AB-system, J=9.5, 4.5 Hz; 2H), 2.88 (t, J=7.5 Hz; 2H), 2.71-2.58 (m; 2H), 2.14-2.08 (m; 1H), 1.81-1.68 (m; 3H), 1.38 (s; 9H); 1.28 (s; 3H), 1.38-1.28 (m; 4H), 0.85 (m; 3H).

Provenance & Evidence