反应详情

5.0 g. (14.64 mmoles) of 6-methyl-9-(N-methylanilino)-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-3-carboxylic acid ethyl ester are dissolved in 100 ml. of chloroform. The solution is heated for 9 hours under reflux and air is bubbled into the reaction mixture. The solvent is distilled off in vacuo. The residue is crystallized from ethanol. 2.9 g. (58.4%) of 6-methyl-9-(N-methyl-anilino)-4-oxo-6,7-dihydro-4H-pyrido[I,2-a]pyrimidine-3-carboxylic acid ethyl ester is obtained which does not give a melting point depression when admixed with the product of Example 7. Melting point: 140°-142° C.

1. temperatureThe solution is heated for 9 hours
2. temperatureunder reflux
3. customair is bubbled into the reaction mixture
4. distillationThe solvent is distilled off in vacuo
5. customThe residue is crystallized from ethanol