Synthesis and biological studies of triazolo-/thiadiazolo-benzoxazines.

Diethyl bromomalonate (2) with an equimolar amount of 2-aminophenol (1) in the presence of sodium fluoride undergoes a cyclization reaction to form 2H,4H-2-ethoxycarbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (3). Furthermore, compound 3 undergoes a condensation reaction with hydrazine hydrate in the presence of methanol to yield 2H,4H-2-hydrazinocarbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (4), which on further reaction with aryl isothiocyanates gave 2H,4H-2-[ (4'-substituted)-phenylthiosemicarbazino]-carbonyl-3,4-dihydro-3-oxo-1,4-benzoxazine (5). Compound 5 on treatment with NaOH, cone.

Synthesis and biological studies of bis (thiadiazole/triazole) by sonication.

5,5-Dimethylcyclohexane-1,3-dione was treated with semicarbazide to yield its acid hydrazide, which on further reaction under ultrasound condition with aryl isothiocyanates gave 1,3-bis-imino-[1-(carboxy)-4-substituted phenylthiosemicarbazide]-5,5-dimethylcyclohexane. This compound in acidic medium gave 1,3-bis-imino-[5-(substituted) phenylamino-1,3,4-thiadiazol-2-yl-]-5,5-dimethylcyclohexane, whereas in basic medium 1,3-bis-imino-[4-(substituted) phenyl-5-mercapto-1,2,4-triazol-3-yl-]-5,5-dimethylcyclohexane was obtained. The synthesized compounds were investigated for their antibacterial activities.