4-Isopropoxybenzenesulfonyl chloride can be used as an organic synthesis intermediate, prepared by reacting isopropoxybenzene with chlorosulfonic acid in the presence of phosphorus pentachloride. It can be used to prepare the compound 5-chloro-3-(2-fluorophenyl)-1-[(4-isopropoxyphenyl)sulfonyl]-6-methoxy-3-[3-(4-methylpiperazin-1-yl)propyl]-1,3-dihydroindole-2-one hydrochloride, which exhibits high affinity and high selectivity for arginine vasopressin (AVP) receptors.
10 g of isopropoxybenzene was cooled to -10C, 21.84 ml of chlorosulfonic acid was added dropwise, followed by 13.68 g of phosphorus pentachloride and the mixture was stirred at -5C for 1 hour. The reaction mixture was poured into 250 ml of ice and water and extracted with DCM, the organic phase was dried over Na2SO4 and the solvent was evaporated off in vacuum. The residue was separated by chromatography on silica gel, eluting with a gradient of cyclohexane/AcOEt mixture from (95/5; v/v) to (85/15; v/v) to obtain the expected compound 4-isopropoxybenzenesulfonyl chloride, Mp=93C.
