Synthesis and Antimicrobial Activity of Some Novel 2,6,7-Trisubstituted-2H-3,4-dihydro-1,4-benzoxazin-3-one Derivatives

The synthesis of a new serie s of 2/-1-3 ,4-dihydro- 1 ,4-bcnzoxazin-3-one derivatives 1-8 is accomplished in order to determine their antimicrobial activities and study th eir structure -ac tivit y relati onships (SA R). The sy nthesized compounds have bee n tested in virro against two Gram-positive, three Gram-negative bacteria and the fungu s Candida a/bicans. The in vi rro act ivit y results show that the sy nthesized compounds cxibit MIC va lu es between 50- 12.5 J..lg/mL for th e antimi crob ial activity against the tes ted microorga ni sms. The antibacterial and antifungal act ivities or the co mpounds 1-8 are al so compared to several standard drugs. Virtanen et a/ 1 - 4 have iso lated 2,4-dihydroxy-1 ,4benzoxazin-3-one (DIBOA) as a glycos ide from rye pl ant. Since th en a number of analogous of I ,4benzoxazine have been fo und in nature. Only, limited number of compound s containin g I ,4 -benzoxazin c rin g sys tem have been studi ed for th eir chemotherap euti c actiVIt y. The most interesting observation that ofloxacin molecule posseses th e I ,4benzoxazine rin g system in it s structure 5 · 6 , prompted us to investigate thi s heterocyc li c nuclei to ascertain if it would offer any advantage over the other known clini ca ll y used antimi crobial drugs.