Cl[C:2]1[C:11]2[C:6](=[CH:7][C:8]([O:12][CH3:13])=[CH:9][CH:10]=2)[N:5]2[CH:14]=[C:15]([C:17]([O:19][CH2:20][CH3:21])=[O:18])[N:16]=[C:4]2[CH:3]=1.C(OCC)(=O)C.C([O-])(=O)C.[Na+]>C(O)C.[Pd]>[CH3:13][O:12][C:8]1[CH:7]=[C:6]2[C:11]([CH:2]=[CH:3][C:4]3[N:5]2[CH:14]=[C:15]([C:17]([O:19][CH2:20][CH3:21])=[O:18])[N:16]=3)=[CH:10][CH:9]=15 g of ethyl 5-chloro-8-methoxyimidazo-[1,2-a]-quinoline-2-carboxylate were suspended in 75 ml of ethanol and 75 ml of ethyl acetate and then 2.5 g of anhydrous sodium acetate and 250 mg of 5% palladium on charcoal were added. The mixture was hydrogenated at 50° C. under atmospheric pressure for 4 hours and the catalyst was filtered off. Then, the solvent was removed under vacuum and the residue was partitioned between chloroform and 2 N sodium carbonate solution. The organic solution was dried over magnesium sulfate and was reduced in volume under vacuum and ether was added to obtain pale cream crystals of ethyl 8-methoxyimidazo-[1,2-a]-quinoline-2-carboxylate melting at 152°-153° C.
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