D-CYCLOHEXYLGLYCINOL

Step 1: To a stirred mixture of LiAlH4 (724 mg, 19.08 mmol) in anhydrous THF (20 mL) at rt was addedportionwise 2-cyclohexyl-D-glycine (1 g, 6.36 mmol). The mixture was heated at 80 °C for 4 h. The mixture was cooled to 0 °C and then water (1 mL), 1M aq NaOH (1 mL), and water (3 mL) were added sequentially. The mixture was filteredand the filtrate was partitioned between a mixture of DCM, 1M aq NaOH, and saturated aq sodium potassium tartrate.The organic layer was separated and further washed with 1M aq NaOH. The organic was separated, dried over MgSO4filtered, and concentrated under reduced pressure to afford (R)-2-amino-2-cyclohexylethanol (400 mg) which was notpurified further. LCMS (ESI) m/z 144 (M+H)+.General procedure: To a stirred suspension of aminoalcohol1 (0.63 mmol) in acetic acid/acetate sodium [1 M] pH = 5(9 mL), was added 1, 4-dithiane-2, 5-dithiol 2 (0.750 mmol). Themixture was heated at reflux for 1 h, cooled and extracted withEtOAc (4 30 mL), then dried (Na2SO4) and filtered. The organiclayer was evaporated under reduced pressure. The crude was purifiedby column chromatography using (n-hexanes/EtOAc) to obtaincompounds 3 and/or 4.Step 2: To a stirred solution of 6-((3H-imidazo[4, 5-b]pyridin-3-yl)methyl)-2-(methylthio)benzo[d]thiazole (670mg, 2.15 mmol) in DCM (25 mL) at 0 C was added 70% meta-chloroperbenzoic acid (582 mg, 2.36 mmol) and themixture was stirred at 0 C for 1 h. To the mixture was added saturated aqueous NaHCO3 and the organic layer wasseparated. The aqueous layer was extracted with DCM and the combined organic layers were washed with saturatedaq NaHCO3. The organic layer was separated, dried over MgSO4 filtered, and under reduced pressure to afford 670mg of a 4:1 mixture of 6-((3H-imidazo[4, 5-b]pyridin-3-yl)methyl)-2-(methylsulfinyl)benzo[d]thiazole and 6-((3H-imidazo[4, 5-b]pyridin-3-yl)methyl)-2-(methylsulfonyl)benzo[d]thiazole as a solid that was not purified further. LCMS (ESI) m/z329 (M+H)+ (consistent with 6-((3H-imidazo[4, 5-b]pyridin-3-yl)methyl)-2-(methylsulfinyl)benzo[d]thiazole) and m/z 345(M+H)+ (consistent with 6-((3H-imidazo[4, 5-b]pyridin-3-yl)methyl)-2-(methylsulfonyl)benzo[d]thiazole). Step 2: A 4:1 mixture of 6-((3H-imidazo[4, 5-b]pyridin-3-yl)methyl)-2-(methylsulfinyl)benzo[d]thiazole and6-((3H-imidazo[4, 5-b]pyridin-3-yl)methyl)-2-(methylsulfonyl)benzo[d]thiazole (120 mg) from Step 2 of Example 63 wasdissolved in anhydrous DMA (2 mL), and then