To a stirred solution of 1-[Bis-(4-hydroxyphenyl)methyl]-1H-[1,2,4]triazole (STX267, 500 mg, 1.87 mmol) in CH2Cl2/MeOH 1:1 (40 ml) at −78° C. under nitrogen, a solution of benzyltrimethylammonium tribromide (1.49 g, 3.74 mmol) in CH2Cl2/MeOH 1:1 (10 ml) was added dropwise over 45 min. The orange mixture was kept at 0° C. for 7 h and then at room temperature overnight, at which time the solution had become colorless. The reaction mixture was evaporated and the residue that obtained was dissolved in a mixture water (100 mL) and EtOAc (100 mL). The aqueous layer was separated and was further extracted with EtOAc (2×50 mL). The organic extracts were combined and washed with brine, dried (Na2SO4) and evaporated. The crude product was fractionated by flash chromatography (hexane/ethyl acetate, 1:3) and the second fraction that collected gave JRL01105 (STX356) (485 mg) as white solid at about 97% purity; δH (400 MHz, DMSO-d6) 6.90 (1H, s, CH), 6.93 (2H, d, J 8.6 Hz), 7.03 (2H, dd, J 2.1 and 8.6 Hz), 7.30 (2H, d, J 2.1 Hz), 8.06 (1H, s), 8.56 (1H, s) and 10.45 (2H, br s, exchanged with D2O, 2×OH). The main impurity was the mono-brominated derivative of STX356. A small quantity of this fraction was further purified by semi-preparative HPLC (Waters PrepLC RP18, 25×10 mm, flow rate: 10 mL/min, mobile phase: MeOH/H2O, 60:40). The fraction with a retention time of 5.5 nm in was collected and upon evaporation gave a white solid; m.p. 198-205° C. (dec.). Found: C, 42.2; H, 2.65; N, 9.79; C15H11Br2N3O2 requires C, 42.38, H, 2.61, N, 9.89.
