Sodium borohydride → 1-[2-(3,4,5-Trimethoxyphenyl)-2-hydroxyethyl]-4-(2-oxo-3,4-dihydro-2H-1,3-benzoxazin-3-yl)-piperidine

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Reaction Steps

In this example, 2.8 g of 1-(3,4,5-trimethoxybenzoylmethyl)-4-(2-oxo-3,4-dihydro-2H-1,3-benzoxazin-3-yl)-piperidine obtained in the same manner as in Example 7 is mixed with 150 ml of methanol. While this mixture is stirred at 0° to 10° C., 1.5 g of sodium borohydride is added thereto over a period of 2 hours. Then, the mixture is stirred overnight at room temperature. The mixture is further mixed with 1 g of sodium borohydride and stirred overnight. The white crystals deposited are separated by filtration, washed with methanol and water and dried to obtain 1.96 g of a crude product. The crude product is recrystallized from ethanol to obtain 1.76 g of the desired product.

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