To 5-[4-(3,5-di-tert-butyl-4-hydroxy-phenylsulfanyl)-piperidine-1-sulfonyl]-1-methyl-1H-pyrrole-2-carboxylic acid methyl ester (Ex. 4a, 436 mg, 0.83 mmol) in 3 mL of DMF was added 3-bromo-propan-1-ol (127 mg, 0.91 mmol) and K2CO3 (343 mg, 2.5 mmol). The mixture was heated to 75° C. for 16 h. Upon cooling to room temperature it was poured into saturated NH4Cl (30 mL). The mixture was extracted with Ethyl acetate (3×30 mL) and the organic extracts were dried over Na2SO4 and concentrated under reduced pressure. Chromatography (3-40% Ethyl acetate/hexanes) gave 5-{4-[3,5-di-tert-butyl-4-(3-hydroxy-propoxy)-phenylsulfanyl]-piperidine-1-sulfonyl}-1-methyl-1H-pyrrole-2-carboxylic acid methyl ester as a pale-yellow thick oil (203 mg). ESI/CI-MS m/z 581 ([M+H]+).
