Water → (+/-)-5-(2-Methyl-propane-2-sulfinylamino)-2-(6-methyl-2-p-tolyl-imidazo[1,2-a]pyridin-3-yl)-pentanoic acid methyl ester

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Reaction Steps

To a magnetically stirred solution of 2-(6-methyl-2-p-tolyl-imidazo[1,2-a]pyridin-3-yl)-5-oxo-pentanoic acid methyl ester 44a (0.066 g, 0.189 mmol) in THF (2 mL) at room temperature under Ar atmosphere was added 2-methyl-propane-2-sulfinic acid amide (0.023 g, 0.189 mmol) and titanium ethoxide (20 wt % solution in ethanol, 2 mL). The reaction mixture was stirred overnight at room temperature. Water (40 mL) was added, and the aqueous phase was extracted with ethyl acetate (2×40 mL). The combined organic layers were washed with water, dried (MgSO4), and concentrated in vacuo. The reaction mixture was redisolved in MeOH (2 mL) and sodium borohydride (0.014 mg, 0.378 mmol) was added at room temperature. The reaction mixture was stirred for 1 h at room temperature, then water (40 mL) was added, and the aqueous phase was extracted with ethyl acetate (2×100 mL). The combined organic layers were washed with water, dried (MgSO4), and concentrated in vacuo to provide crude product.

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