Phosphorus oxychloride → 7-chloro-2-heptylthio-6-methyl-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one
Reaktionsgleichung
[CH2:1]([S:8][C:9]1[S:20][C:12]2=[N:13][C:14](O)=[C:15]([CH3:18])[C:16](=[O:17])[N:11]2[N:10]=1)[CH2:2][CH2:3][CH2:4][CH2:5][CH2:6][CH3:7].P(Cl)(Cl)([Cl:23])=O.P(Cl)(Cl)(Cl)(Cl)Cl>>[Cl:23][C:14]1[N:13]=[C:12]2[S:20][C:9]([S:8][CH2:1][CH2:2][CH2:3][CH2:4][CH2:5][CH2:6][CH3:7])=[N:10][N:11]2[C:16](=[O:17])[C:15]=1[CH3:18]Komponenten
4
Versuchsvorschrift
A mixture of 19.5 g of the thus obtained 2-heptylthio-7-hydroxy-6-methyl-5H-1,3,4-thiadiazolo-[3,2-a]pyrimidin-5-one, 38 g of phosphorus oxychloride and 13.6 g of phosphorus pentachloride was warmed to 77°~88° C. and was stirred for 2 hours. The reaction solution was concentrated under reduced pressure, thereafter the residue was dissolved in toluene, and the solution was washed with a potassium carbonate aqueous solution and water respectively. After the solution was dried over anhydrous sodium sulfate, the solvent was distilled off and the residue was purified by column chromatography on a silica gel with an ethyl acetate/n-hexane (2:3) mixture as an eluent. After the solvent was distilled off, 19.0 g of 7-chloro-2-heptylthio-6-methyl-5H-1,3,4-thiadiazolo-[3,2-a]pyrimidin-5-one was obtained.