CS([Cl:5])(=O)=O.[Cl:6][C:7]1[C:8]([CH:22](O)[CH3:23])=[C:9]2[C:14](=[CH:15][C:16]=1[Cl:17])[N:13]=[C:12]([O:18][CH3:19])[C:11]([O:20][CH3:21])=[N:10]2.C(N(CC)CC)C>ClCCl.[Cl-].C([N+](CCCC)(CCCC)CCCC)CCC.[Cl-].[Na+].O>[Cl:5][CH:22]([C:8]1[C:7]([Cl:6])=[C:16]([Cl:17])[CH:15]=[C:14]2[C:9]=1[N:10]=[C:11]([O:20][CH3:21])[C:12]([O:18][CH3:19])=[N:13]2)[CH3:23]Methanesulphonyl chloride (239 mg, 2.09 mmol) was added to a solution of 6,7-dichloro-2,3-dimethoxy-5-(1-hydroxyethyl)quinoxaline (527 mg, 1.74 mmol) (Preparation 2) and triethylamine (264 mg, 2.61 mmol) in dry dichloromethane (20 mL) at 20° C. The mixture was stirred for 30 minutes, then tetra-n-butyl ammonium chloride (726 mg, 2.61 mmol) was added in portions. After a further 30 minutes at 20° C., brine (20 mL) was added and the organic layer separated. The aqueous layer was extracted with dichloromethane (2×20 mL), and the combined extracts were dried (MgSO4) and concentrated under reduced pressure. Purification by flash chromatography using hexane/dichloromethane (1:1) gave 5-(1-chloroethyl)-6,7-dichloro-2,3-dimethoxyquinoxaline (95 mg, 17%), as a white solid.
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