Phosphorus oxychloride → Ethyl 4-chloro-2-(pyrimidin-2-yl)pyrimidine-5-carboxylate
Reaktionsgleichung
[CH2:1]([O:3][C:4]([C:6]1[C:7](O)=[N:8][C:9]([C:12]2[N:17]=[CH:16][CH:15]=[CH:14][N:13]=2)=[N:10][CH:11]=1)=[O:5])[CH3:2].C([O-])(O)=O.[Na+].O=P(Cl)(Cl)[Cl:26]>>[CH2:1]([O:3][C:4]([C:6]1[C:7]([Cl:26])=[N:8][C:9]([C:12]2[N:17]=[CH:16][CH:15]=[CH:14][N:13]=2)=[N:10][CH:11]=1)=[O:5])[CH3:2]Komponenten
4
Versuchsvorschrift
A suspension of 1.62 g (6.5 mmol) 4-hydroxy-[2,2′]bipyrimidinyl-5-carboxylic acid ethyl ester in 16 ml POCl3 was heated at reflux for lh. The solution was cooled to RT and poured into 100 ml ice-water. The pH of the solution was adjusted to 8 with sat. NaHCO3-solution. The water phase was extracted three times with 80 ml CH2Cl2. The combined organic phases were dried (Na2SO4), filtered and evaporated. The residue was purified by chromatography (SiO2, CH2Cl2/MeOH 95:5) to give 1.43 g (82%) 4-chloro-[2,2′]bipyrimidinyl-5-carboxylic acid ethyl ester as a light brown solid, MS (EI): 264.1 (M+).