Hydrochloric Acid → 3-(4-((2-Aminoethyl)amino)-1,2,5-oxadiazol-3-yl)-4-(3-bromo-4-fluorophenyl)-1,2,4-oxadiazol-5(4H)-one hydrochloride

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Reaction Steps

In a 22 L flask was charged hydrogen chloride (4 N solution in 1,4-dioxane, 4 L, 16 mol). tert-Butyl [2-({4-[4-(3-bromo-4-fluorophenyl)-5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl]-1,2,5-oxadiazol-3-yl}amino)ethyl]carbamate (2315 g, 4.77 mol) was added as a solid in portions over 10 min. The slurry was stirred at room temperature and gradually became a thick paste that could not be stirred. After sitting overnight at room temperature, the paste was slurried in ethyl acetate (10 L), filtered, re-slurried in ethyl acetate (5 L), filtered, and dried to a constant weight to afford the desired product as a white solid (combined with other runs, 5 kg starting material charged, 4113 g, 95%). LCMS for C12H11BrFN6O3 (M+H)+: m/z=384.9, 386.9. 1H NMR (400 MHz, DMSO-d6): δ 8.12 (m, 4H), 7.76 (m, 1H), 7.58 (t, J=8.7 Hz, 1H), 6.78 (t, J=6.1 Hz, 1H), 3.51 (dd, J=11.8, 6.1 Hz, 2H), 3.02 (m, 2H).

Provenance & Evidence