Boron tribromide → HCID 178464670, compound

Participants

Reaction Steps

Under N2 atmosphere, to a solution of 1.05 g N-[ethylamino-(5-phenyl-4,5-dihydro-pyrazol-1-yl)-methylene]-4-methoxy-benzenesulfonamide in 25 mL DCM, 12.91 mL of a 1M solution of boron tribromide in DCM was added. The mixture was stirred overnight at room temperature under N2 atmosphere, quenched with water, and stirred for another 30 minutes. The solids were filtered off and the filtrate was extracted with water. The organic layer was dried over MgSO4 and evaporated to dryness. The residue was purified by flash chromatography (stepwise gradient DCM→DCM/MeOH 95:5). The pure fractions were concentrated and triturated with Et2O. The solids were filtered off and dried in vacuo to give 0.34 g (34%) of N-[ethylamino-(5-phenyl-4,5-dihydro-pyrazol-1-yl)-methylene]-4-hydroxy-benzenesulfonamide as a grey crystalline material, m.p. 158-160° C. 1H NMR (400 MHz, DMSO-d6) δ 1.07 (t, J=7.2 Hz, 3H), 2.69-2.81 (m, 1H), 3.36-3.47 (m, 1H), 3.49-3.59 (m, 2H), 5.40-5.51 (m, 1H), 6.55 (d, J=8.7 Hz, 2H), 7.00 (d, J=8.4 Hz, 2H), 7.04-7.12 (m, 3H), 7.22-7.29 (m, 3H), 9.71 (s, 1H) [guanidine NH invisible].

Provenance & Evidence