Water → trans-3-acetoxy-6-cyano-3,4-dihydro-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-t-butyldimethylsilyloxymethyl-1-pyridinyl)-2H-benzo[b]pyran

Participants

Reaction Steps

In 15 ml of anhydrous methylene chloride, is dissolved 1.32 g of trans-3-hydroxy-6-cyano-3,4-dihydro-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-t-butyldimethylsilyloxymethyl-1-pyridinyl)-2H-benzo[b]pyran obtained in Example 1. Then, 0.49 ml of pyridine and 73 mg of 4-dimethylaminopyridine are added. Then, 0.43 ml of acetic anhydride is dropped thereinto at 0° C. and reacted at room temperature for 30 minutes. After stopping the reaction by adding water to the reaction mixture, it is extracted with ether. The organic layer is successively washed with water and saturated aqueous 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 1/3 mixture of ethyl acetate/methylene chloride as a developing solvent to obtain 1.45 g of trans-3-acetoxy-6-cyano-3,4-dihydro-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-t-butyldimethylsilyloxymethyl-1-pyridinyl)-2H-benzo[b]pyran.

Provenance & Evidence