karbala journal of pharmaceutical sciences

In the present research, a series of Formazans derivatives 7a-j have been prepared by
the condensation of Schiff bases (4,5) and diazonium salt of substituted aromatic amines
Heterocycl, 6a-e. The intermediate Schiff bases (4,5), was itself synthesized by condensation of2-
amino benzothiazole (1), with 4-nitro and dimethylamino benzaldehyde, (2,3). All the reaction
were routinely monitored and purity was determind on thin layer chromatography using coated
aluminum plates and spots were visualized by exposing the dry plates in iodine vapours.The
structures of the compounds have been confirmed by , Mass spectroscopy 1H NMR, U.V, IR
spectral data and melting points. The antibacterial activity of the compounds has also been
screened.

Four n-alkyl azides; n-heptyl azide, n-octyl azide, n-decyl azide and n-dodecyl azide (1a-d) were prepared via SN2 reaction of alkyl halides and sodium azide. In different step, D-fructose was converted to 2,3:4,5-di-O-isopropylidene-D-fructopyranose (3) using acetone and sulfuric acid as catalyst. The reaction of compound (3) with propargyl bromide in DMF afforded the terminal acetylene (4) in very good yield. The derivative (4) was reacted with synthesized n-alkyl azides (1a-d) via cycloaddition reaction using Cu(I) as catalyst afforded D-fructose based 1,2,3-triazoles (5a-d). The acetal groups of triazoles (5a-d) were removed under acidic conditions to give the deprotected triazoles (6a-d). All synthesized compound were identified by TLC, FTIR and most of them were characterized by 1H NMR, 13C NMR, COSY, HSQC and HRMS. The synthesized compounds showed antibacterial activity in vitro against two kinds of bacteria: Escherichia coli (-) and Staphylococcus aureus (+).

Some novel Schiff bases linked to phthalimide moiety have been synthesized via multistep synthesis. The first step involved reaction of phthalic anhydride with aniline producing N-phenyl phthalamic acid which was subsequently dehydrated to the corresponding N-phenyl phthalimide via treatment with acetic anhydride and anhydrous sodium acetate. The synthesized imide was treated with chlorosulfonic acid in the third step producing 4-(N-phthalimidyl)phenyl sulfonyl chloride which on amination with hydrazine hydrate in the fourth step afforded 4-(N-phthalimidyl)phenyl sulfonyl hydrazine and this in turn when introduced in condensation reaction with various aromatic aldehydes and ketones afforded the desirable new Schiff bases.
Structures of the prepared compounds were elucidated on the basis of FTIR, 1HNMR and 13CNMR spectral data which agreed with the proposed structures.
The synthesized compounds were screened for their antibacterial activity against two microorganisms Staphylococcus aureus and Escherichia Coli and they were found to exhibit good to moderate antibacterial activity.