Phosphorus oxychloride → 1218765-14-0
Reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[NH:9][C:8](=O)[C:7]([CH3:14])=[N:6]2.COC1C=C2C(N=C(C)C(=O)N2)=CC=1.O=P(Cl)(Cl)[Cl:31]>>[Cl:31][C:8]1[C:7]([CH3:14])=[N:6][C:5]2[C:10](=[CH:11][CH:12]=[C:3]([O:2][CH3:1])[CH:4]=2)[N:9]=1Participants
Procedure
A solution of 6-methoxy-3-methylquinoxalin-2(1H)-one & 7-methoxy-3-methylquinoxalin-2(1H)-one (1.2 g, 6.31 mmol) in POCl3 (10 ml) was refluxed for 3 h. The solvent was evaporated under reduced pressure and the residue was diluted with cold water. The aqueous solution was basified by solid sodium carbonate and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, filtered and evaporated under reduced pressure to get crude compound. The crude compound was purified by silica gel chromatography (20% ethyl acetate in pet ether) to get regioisomers as a mixture. The mixture of regioisomers were separated by SFC purification to afford 2-chloro-6-methoxy-3-methylquinoxaline (0.51 g, 38.7%) and 3-chloro-6-methoxy-2-methylquinoxaline (required isomer) (0.48 g, 36.5%) as off white solids.
Workup
- customThe solvent was evaporated under reduced pressure
- additionthe residue was diluted with cold water
- extractionextracted with ethyl acetate
- dry with materialThe organic layer was dried over anhydrous sodium sulfate
- filtrationfiltered
- customevaporated under reduced pressure
- customto get crude compound
- customThe crude compound was purified by silica gel chromatography (20% ethyl acetate in pet ether)
- customto get regioisomers as a mixture
- additionThe mixture of regioisomers
- customwere separated by SFC purification
Sources & evidence
- ORD record
- ord-bf2a76f011f448bd890b27055ae35106
- Source dataset
- uspto-grants-2015_02
- Patent number
- US08957203B2
Reaction notes
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