[I-].[Na+].C(=O)([O-])[O-].[Na+].[Na+].[NH2:9][C:10]1[C:11]2[N:12]([C:16]([CH3:20])=[C:17]([CH3:19])[N:18]=2)[CH:13]=[CH:14][CH:15]=1.[CH3:21][C:22]1[C:27]([CH2:28]Cl)=[C:26]([N+:30]([O-:32])=[O:31])[CH:25]=[CH:24][CH:23]=1>CC(C)=O>[CH3:21][C:22]1[C:27]([CH2:28][NH:9][C:10]2[C:11]3[N:12]([C:16]([CH3:20])=[C:17]([CH3:19])[N:18]=3)[CH:13]=[CH:14][CH:15]=2)=[C:26]([N+:30]([O-:32])=[O:31])[CH:25]=[CH:24][CH:23]=115.0 g of sodium iodide and 31.0 g of sodium carbonate are added at RT to a solution of 8-amino-2,3-dimethylimidazo[1,2-a]pyridine (14.7 g) and 6-methyl-2-nitrobenzyl chloride (18.6 g) in 100 ml of acetone and the mixture is then heated at boiling under reflux for 6 h. After cooling the solution to RT and concentrating, the residue is dissolved in a mixture of 200 ml of ethyl acetate and 200 ml of water and the organic phase is separated off. After three further extractions with 100 ml of ethyl acetate each, the combined organic phases are dried over magnesium sulfate and then concentrated to 80 ml. 12.1 g of the title compound crystallize as a slightly yellow solid. The mother liquor is concentrated. Chromatographic purification of the residue on silica gel (eluent: toluene/dioxane=6:1) gives a further 14 g of the crystalline product. Recrystallization of both fractions from ethyl acetate gives 21.5 g (76%) of the title compound of m.p. 160-162° C.
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