Synthesis and pharmacological activities of 1,8-naphthyridine derivatives

In the present study, a series of 2-substituted-4-methyl-7-amino/4,7-dimethyl-1,8-naphthyridines were synthesized and characterized by IR, H-1-NMR and elemental analysis. The compounds were investigated for anticonvulsant (125. 250 mg/kg), cardiac and antimicrobial activities. The compounds were screened for antibacterial activity against gram (+) bacteria (Staphylococcus epidermidis, Bacillus subtilis, Enterococcus faecalis and Micrococcus luteus) and gram (-) bacteria (Proteus vulgaris, Pseudomonas aeruginosa. Escherichia coli and Salmonella 4-phi). All the compounds except 2-(3'-phenylaminoproploxy)-4-methyl-1-7-amino-1,8-naphthyridine exhibited significant anticonvulsant activity. The anticonvulsant activity of 2-(3-morpholino-2'-hydroxyproploxy)-4methyl-1-7-amino-1,8-naphthyridine, 2-(3'-diphenylamino-2'-hydroxypropyloxy)-4-methvI-7-amino- 1,8-naphthyridine and 2-(3'-diethanolamino-propyloxy)-4,7-dimethy-1,8-naphthyridine at the dose of 250 mg/kg were found to p. be equivalent to diazepam (5 mg/kg). Sympathetic blocking activity ss as observed with 2-(3'-phenylamino-2'-hydroxyproploxy-4-methyl-7-amino-1,8-naphthyridine, 2-(3'-diethanolamino-2'-hydroxypropyloxy)-4-methyl-1-7-amino-1,8-naphthyridine and 2-(3'-diphenylamino-2'-hydroxyproploxy)-4-methyl-7-amino-1,8-naphthyridine only. All the compounds were devoid of antibacterial activity against the tested bacteria.