Synthesis, Characterization and Antimicrobial Screening of Some Bioactive 1,8-Naphthalimide Derivatives.

Abstract

This research include developing new heterocyclic derivatives of 1,8-naphthalimides bearing oxazoline, thiazoline, oxadiazole, thiadiazole and aminotriazole moieties as the following steps: N-ester-1,8-naphthalimide (1) was obtained by direct imidation of 1,8- naphthalic anhydride with ethylglycinate in dimethylsulfoxide. Compound (1) was treated with hydrazine hydrate in absolute ethanol to give N-acetohydrazide-1,8-naphthalimide (2).
N-Acetophenylsemicarbazide-1,8-naphthalimide (3) and N-Aceto phenylthiosemicarbazide- 1,8-naphthalimide (7) were synthesized via reaction of compound (2) with phenylisocyanate and phenylisothiocyanate in absolute ethanol respectively.
Cyclization of compounds (3) and (7) with p-substituted phenacyl bromide gives the oxazoline derivatives (4-6) and thiazoline derivatives (9-11) respectively. N-Methyl-[(5- (phenyl amino)-1,3,4-thiadiazol-2-yl)]-1,8-naphthalimide (8) prepared via treatment of compound (7) with phosphoric acid. Reaction of the prepared hydrazide (2) with carbon disulfide in the presence of potassium hydroxide producing N-Methyl-[potassium dithiocarbazate]-1,8-naphthalimide (12). Acidifying of the obtained salt (12) with 4N hydrochloric acid give N-Methyl-[1,3,4-oxadiazol-2-yl-5-thiol]-1,8-naphthalimide (13). The obtained salt (12) also treated with hydrazine hydrate to afford the desirable N-Methyl-[1,2,4- triazol-3-yl-4-amino-5-thiol]-1,8-naphthalimide (14).
All the prepared compounds in this research were characterized by recording their melting points, FTIR, 1HNMR, 13CNMR spectra, checked by TLC, physical properties and some specific chemical tests also. Some of the new prepared compounds were evaluated for the antimicrobial screening in vitro against two types of Gram positive bacteria including (Staphylococcus aureus, Bacillus subtilis) and two types of Gram negative bacteria including (Escherichia coli, Pseudomonas aeuroginosa).
More, antifungal activities of some prepared compounds performed against the yeastlike pathogenic fungus (Candida albicans). The antimicrobial screening carried out in three concentrations of prepared compounds. Sulfamethoxazole/Clotrimazole was used as standard drugs. The results showed that most of the tested compounds have good biological activity against the mentioned organisms compared with standard drugs above