Acetic Anhydride → HCID 19813417, compound

Participants

Reaction Steps

In 16 ml of acetic acid was dissolved 1.87 g (5.5 mmol) of 3,5-dimethoxycarbonyl-2-formyl-1,4-dihydro-6-methyl-4-(3 -ethynylphenyl)pyridine obtained in Example 15. Thereto were added 0.45 g (6.5 mmol) of hydroxylamine hydrochloride and 0.67 g (8.2 mmol) of sodium acetate. The admixture was stirred for 2.5 hours at room temperature. Then 1.96 g (19.2 mmol) of acetic anhydride was added thereto, and the admixture was reacted for 1.5 hours at room temperature, further for 4 hours at 95°-100° C. After completing the reaction, the reaction solution was concentrated under reduced pressure, water was added to the residue. After neutralization of the reaction mixture with saturated solution of sodium hydrogencarbonate, the reaction mixture was extracted with ethyl acetate several times. The organic layer thereof was washed with water, dehydrated and concentrated. The residue was purified by subjecting to silica gel column chromatography [eluent: benzene-ethyl acetate (10 : 1)] and recrystallized from the mixture of ethyl acetate and n-hexane to give 1.2 g of the desired compound as yellow prism crystals (yield: 66.7%).

Provenance & Evidence