反应详情

Add 2-[(6-methyl-pyridin-2-ylamino)-methylene]-malonic acid diethyl ester (14.8 g) to the refluxing phenyl ether (100 ml) over a period of 5 min under nitrogen. After the addition is complete, keep the reaction under reflux for 3 h. Cool it to room temperature, and then pour the reaction mixture into 1:1 hexane/ethyl acetate (2000 ml). Collect the brown precipitate by filtration to obtain 7-methyl-4-oxo-1,4-dihydro-[1,8]naphthyridine-3-carboxylic acid ethyl ester (8.35 g, 72% for two steps). MS (ES+): 233 (M+H); (ES−): 231 (M−H).

1. additionAfter the addition
2. customthe reaction
3. temperatureunder reflux for 3 h
4. customCollect the brown precipitate
5. filtrationby filtration