Annulation of 6-aminouracils with 2,3-dimethoxy- and 2-fluorobenzaldehydes and 2-chloro-7-methoxyquinoline-3-carbaldehyde

6-R-Aminouracils reacted with 2,3-dimethoxybenzaldehyde to give 10-R-substituted 9-methoxy-5-deazaflavins. No expected 5-deazaflavins were obtained in analogous reactions of 2,3-dimethoxybenzaldehyde with 6-aminouracil hydrochlorides. On the other hand, the corresponding 5-deazaflavin and naphthyridine hydrochlorides were formed in the reactions of 6-aminouracil hydrochlorides with 2-fluorobenzaldehyde and 2-chloro-7-methoxyquinoline-3-carbaldehyde. The newly synthesized 9,10-substituted 5-deazaflavins and benzo[b]pyrimido[5,4-g][1,8]naphthyridines attract interest as potential biologically active substances and substrates for further structural modifications.