Phosphorus oxychloride → 7-chloro-2-hexylthio-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one
Reaction equation
[CH2:1]([S:7][C:8]1[S:18][C:11]2=[N:12][C:13](O)=[CH:14][C:15](=[O:16])[N:10]2[N:9]=1)[CH2:2][CH2:3][CH2:4][CH2:5][CH3:6].P(Cl)(Cl)(Cl)(Cl)[Cl:20].P(Cl)(Cl)(Cl)=O>>[Cl:20][C:13]1[N:12]=[C:11]2[S:18][C:8]([S:7][CH2:1][CH2:2][CH2:3][CH2:4][CH2:5][CH3:6])=[N:9][N:10]2[C:15](=[O:16])[CH:14]=1Participants
4
Procedure
A mixture of 23.5 g of the thus obtained 2-hexylthio-7-hydroxy-5H-1,3,4-thiadiazolo[3,2-a]-pyrimidin-5-one, 17.8 g of phosphorus pentachloride and 50.4 g of phosphorus oxychloride was heated to 65°~90° C. and was stirred for 2 hours. The reaction mixture was concentrated under reduced pressure. The residue was dissolved in toluene. The solution was washed with a potassium carbonate aqueous solution and water respectively, and dried over anhydrous sodium sulfate. The solvent was distilled off, and the residue was separated by silica gel column chromatography using an ethyl acetate/toluene mixture as an eluent, and 10.2 g of 7-chloro-2-hexylthio-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one was obtained. m.p. 95°~96° C. Yield 41%.
Workup
- temperaturewas heated to 65°~90° C.
- concentrationThe reaction mixture was concentrated under reduced pressure
- dissolutionThe residue was dissolved in toluene
- washThe solution was washed with a potassium carbonate aqueous solution and water respectively
- dry with materialdried over anhydrous sodium sulfate
- distillationThe solvent was distilled off
- customthe residue was separated by silica gel column chromatography
Sources & evidence
- ORD record
- ord-c788b6ad0aca4b15b1c826d2fdff386b
- Source dataset
- uspto-grants-1990_11
- Patent number
- US04971971
Reaction notes
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