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

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Reaction Steps

In 10.5 ml of methanol, is dissolved 1.04 g of 6-cyano-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-t-butyldimethylsilyloxymethyl-1-pyridinyl)-2H-benzo[b]pyran obtained in Example 8. Then, 2.59 ml of a 4N hydrochloric acid in dioxane is added to the solution at 0° C., and the resulting mixture is reacted at room temperature for 2 hours. The reaction mixture is concentrated under reduced pressure, the residue is mixed with ethyl acetate and water and the product is extracted into the ethyl acetate. The organic layer is washed with saturated aqueou solution of sodium chloride and dried over anhydrous sodium 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 1/20 mixture of methanol/methylene chloride as a developing solvent to obtain 0.76 g of 6-cyano-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-hydroxymethyl-1-pyridinyl)-2H-benzo[b]pyran.

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