Abstract:To improve and optimize the synthetic process of 3-amino-2(1H)-quinolone ring, 3-amino-7,8-dimethoxyl-2(1H)-quinolone (VII) was synthesized by the reduction of 3-nitro-7,8-dimethoxyl-2(1H)-quinolone (IV), which was prepared by the cyclization of 2-amino-3,4-dimethoxylbenzaldehyde (V) with methyl nitroacetate. The compound V was successively prepared from vanillin via actylation, nitrolation, methylation and reduction. The results showed that preferred synthetic conditions were as following: the piperidine catalyzed the cyclization reaction in the mixed solvent of toluene and cyclohexane in volume ratio 7: 3, the 5% Pd/C and ammonium formate were used as the reduced system to reduce the compound VI. The synthetic yield of the 3-amino-7,8-dimethoxyl-2(1H)-quinolone could reach higher than 70%, calculated from the O-aminobenzaldehyde V.