Triethylamine → 2-[[4-[4-(3-Bromo-4-fluorophenyl)-5-oxo-1,2,4-oxadiazol-3-yl]-1,2,5-oxadiazol-3-yl]amino]ethyl methanesulfonate

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-(3-bromo-4-fluorophenyl)-3-{4-[(2-hydroxyethyl)amino]-1,2,5-oxadiazol-3-yl}-1,2,4-oxadiazol-5(4H)-one (1.5 kg, 3.9 mol, containing also some of the corresponding bromo-compound) in ethyl acetate (12 L) was added methanesulfonyl chloride (185 mL, 2.4 mol) dropwise over 1 h at room temperature. Triethylamine (325 mL, 2.3 mol) was added dropwise over 45 min, during which time the reaction temperature increased to 35° C. After 2 h, the reaction mixture was washed with water (5 L), brine (1 L), dried over sodium sulfate, combined with 3 more reactions of the same size, and the solvents removed in vacuo to afford the desired product (7600 g, quantitative yield) as a tan solid. LCMS for C13H11BrFN5O6SNa (M+Na)+: m/z=485.9, 487.9. 1H NMR (400 MHz, DMSO-d6): δ 8.08 (dd, J=6.2, 2.5 Hz, 1H), 7.72 (m, 1H), 7.58 (t, J=8.7 Hz, 1H), 6.75 (t, J=5.9 Hz, 1H), 4.36 (t, J=5.3 Hz, 2H), 3.58 (dd, J=11.2, 5.6 Hz, 2H), 3.18 (s, 3H).

Provenance & Evidence