Hydrochloric Acid → 6-cyano-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-(3-hydroxypropyl)-1-pyridinyl}-2H-benzo[b]pyran

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Reaction Steps

In 16 ml of dioxane, is dissolved 617 mg of 6-cyano-2,2-dimethyl-4-{1,2-dihydro-2-oxo-4-(2-ethoxycarbonylethyl)-1-pyridinyl}-2H-benzo[b]pyran obtained in Example 33. Then, 16 ml of an aqueous solution containing 617 m of sodium borohydride is added at room temperature and reacted first at room temperature for 1.5 hours and then at 60° C. for one hour. After stopping the reaction by adding 20 ml of 2M aqueous hydrochloric acid, the reaction mixture is extracted with ethyl acetate. The organic layer is washed with saturated aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate. The inorganic matter is filtered off and the filtrate is concentrated under reduced pressure. The residue is purified by silica gel column chromatography using 1/10 mixture of methanol/methylene chloride as a developing solvent. Thus, 493 mg of 6-cyano-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-(3-hydroxypropyl)-1-pyridinyl}-2H-benzo[b]pyran is obtained.

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