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

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Reaction Steps

In 15.0 ml of methanol, is dissolved 1.45 g of trans-3-acetoxy-6-cyano-3,4-dihydro-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-t-butyldimethylsilyloxy-1-pyridinyl)-2H-benzo[b]pyran obtained in Example 4. Then, 3.00 ml of 4N hydrochloric acid in dioxane is added thereto at 0° C. and reacted at room temperature for 2 hours. The reaction mixture is concentrated under reduced pressure, the residue is mixed with water and ethyl acetate, and the product is extracted by ethyl acetate. The organic layer is washed with saturated aqueous solution of sodium chloride and dried over anhydrous sodium sulfate. Then, the inorganic matter is filtered off and the filtrate is concentrated under reduced pressure. The residue is purified by silica gel column chromatography using ethyl acetate as a developing solvent to obtain 1.06 g of trans-3-acetoxy-6-cyano-3,4-dihydro-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-hydroxymethyl-1-pyridinyl)-2H-benzo[b]pyran.

Provenance & Evidence