81937-39-5

81112-08-5

105-53-3

81937-39-5

Example A29: Diethyl malonate (0.16 mol) was slowly added dropwise to a suspension of anhydrous dimethylformamide (90 mL) containing sodium hydride (7.631 g, 0.159 mol) under nitrogen protection. The reaction mixture was heated to 50 °C and maintained for 90 minutes. Subsequently, 1-(4-acetylaminophenyl)-2-chloro-1-propanone (37.462 g, 0.166 mol) was added to the reaction system and the temperature was raised to 80 °C to continue the reaction for 3 hours. Upon completion of the reaction, the mixture was cooled and poured into ice water (1 L), washed with saturated sodium chloride solution, followed by full extraction with ethyl acetate. The organic phases were combined, dried with anhydrous sodium sulfate, filtered and treated with activated carbon and finally concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to give 45.0 g of a colorless oily product in 80% yield with an Rf value of 0.7 (El:EE).IR (KBr) showed absorption peaks at 1747, 1732, 1676 cm^-1 (CO). Mass spectrometry analysis showed a molecular ion peak M+ of 349.