Hydrochloric Acid → HCID 23513725, compound

Participants

Reaction Steps

A solution of 1-(5-chlorobenzimidazol-2-ylsulphonyl)-4-(t-butyloxycarbonyl)piperazine (860 mg, 2.15 mmol) in dichloromethane/methanol (15 ml of 1:1) was treated with an excess of hydrogen chloride gas as a saturated solution in ethyl acetate. After stirring for 4 hrs. the solvent was removed in vacuo and the residue dried under high vacuum. This was then suspended in DMF and treated sequentially with 4-(4-pyridyl)benzoic acid (428 mg, 2.15 mmol), triethylamine (0.6 ml, 4.3 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDAC, 495 mg, 2.68 mmol). After stirring overnight the solvent was removed in vacuo and the residue taken up in dichloromethane (50 ml). This was washed sequentially with water, saturated sodium bicarbonate solution, water and brine. Evaporation of the solvent gave a residue which was purified by chromatography (MPLC on Merck Art 9385 silica, gradient eluting with ethyl acetate containing 0-8.0% methanol) to give 1-(5-chlorobenzimidazol-2-ylsulphonyl)-4-[4-(4-pyridyl)benzoyl]piperazine as colourless crystals (370 mg) from ethanol, m.p. 242-244° C., 1H NMR (d6DMSO) 3.0-3.4 ppm (broad s, 4H), 3.4-3.8 ppm (broad s, 4H), 7.4 ppm (d, 1H), 7.5 ppm (d, 2H), 7.6-7.8 ppm (m, 4H), 7.85 ppm 2H), 8.6 ppm (d, 2H), 14.0 ppm (broad s, 1H); MS (M+H)+ 482/484.

Provenance & Evidence