Aluminium lithium hydride → 2,6-Di-tert-butyl-4-[1-(5-hydroxymethyl-1H-imidazole-2-sulfonyl)-piperidin-4-ylsulfanyl]-phenol

To 2-[4-(3,5-di-tert-butyl-4-hydroxy-phenylsulfanyl)-piperidine-1-sulfonyl]-3H-imid-azole-4-carboxylic acid ethyl ester (Ex. 8b, 190 mg, 0.36 mmol) in 3 mL of THF was added 1 mL of 1 M LiAlH4 solution (1 mmol). The reaction was stirred at room temperature for 1 h and then quenched with saturated NaH2PO4 (20 mL). The mixture was diluted with 30 mL of Ethyl acetate and stirred for 10 min and let sit for 1 h. The layers were separated and the aqueous layer was extracted with Ethyl acetate (30 mL). The combined organic phase was dried over Na2SO4 and concentrated under reduced pressure. Chromatography (1-8% Methanol/dichloromethane) gave the title compound as a white solid (125 mg, 72%), mp 122-123° C. 1H NMR (400 MHz, CDCl3): δ 7.23 (s, 2H), 7.07 (s, 1H), 5.29 (s, 1H), 4.65 (s, 2H), 3.72 (m, 2H), 2.88-2.81 (m, 3H), 1.97 (m, 2H), 1.64 (m, 2H), 1.41 (s, 18H). ESI/CI-MS m/z 482 ([M+H]+), 480 ([M−H]−). Two HPLC (reverse-phase, C, 8) methods were used to determine the purity of the title compound. Method 1: gradient elution, 60% to 85% solvent B (A=aqueous 0.1% H3PO4, B=MeCN) in 15 min. Purity (UV-VIS): 98.3% (238 nm); Method 2: gradient elution, 40% to 95% solvent B (A=10 mM NH4OAc, B=MeCN) in 6 min. Purity (UV-VIS λ): 98.5% (215 nm), 99.5% (254 nm), 99.5% (280 nm).