Microwave Assisted Synthesis of phthal and maleimide derivatives with Studying of Antimicrobial Activities.

: A series of phthal and maleimide compounds have been synthesized by the condensation reaction of phthalic and maleic anhydride with four different amino compounds. The structures of all the synthesized compounds were characterized using ( 1 HNMR, 13 CNMR, IR and UV. VIS.) spectral analysis. The synthesized compounds were screened for their anti-microbial activity. The results show that the compounds 1 and 3 exhibited good to moderate activity gainst Gram-positive and negative bacteria. while the compound 8 had no effect organism. Finally, the other compounds exhibit moderate to low activity on all gram-positive and negative bacteria under study.


INTRODUCTION
he preparation of imides has received considerable attention during recent years. Imides are versatile intermediates in the synthesis of nitrogencontaining heterocycles [1,2] . The imide functionality is also an important component in many natural products that exhibit a broad range of activities including immunosuppressants [3] . Imide derivatives are a valuable group of bioactive compounds showing androgen receptor antagonists [4] , anti-inflammatory [5] , anxiolytic [6] , antiviral [7] , antibacterial [8] ,and antitumor [9] properties. Microwave (MW) irradiation has gained popularity in the past decade as a powerful tool for rapid and efficient synthesis of a variety of compounds because of selective absorption of microwave energy by polar molecules. The application of MW irradiation to provide enhanced reaction rate and improved product field in chemical synthesis has been extending to modern drug discovery in complex multistep synthesis and it is proving quite successful in the formation of a variety of carbon-heteroatom bonds [10] . Structures of all synthesized compounds and their in vitro activities were also investigated.

Experimental
All melting points are uncorrected and were determined by open end capillary tube method in Gallen Kamp MFB-600-Melting Point apparatus . The reactions were made by using Microwave Oven Russell hobbs 850 watt. The FTIR spectra were recorded on a Shimadzu FT-IR 8400s spectrophotometer using KBr discs. 1H-NMR spectra were recorded on Burker DMX-500 NMR SPECTROPHOTOMETER on a 300 MHz, with TMS as internal standard and DMSO as solvent . UV-VIS. spectrophotometer using UV-VIS.1650PC spectrophotometer and absolute ethanol as solvent. The physical data of all the synthesized compounds is presented in Table 1.

Synthesis
The synthesis of imides 1-8 was achieved by microwave irradiation technique, which briefly consists of the following. [11,12] Maleic or phthalic anhydride was thoroughly grounded with appropriate solid arylamine in a dry mortar with the help of a pestle to make an easy flowing powder. This material was subsequently taken in a dry conical flask. The mixture was irradiated under microwave for (2-15min) at 800 W, 2450MHz with constant shaking. After completion of the reaction, the contents of the flask were cooled down until the liquid solidified. It was then inverted and the walls were scraped out to give the compounds 1-8. The residue was recrystallised from chloroform.

Antibacterial Activity Tests
The compounds were investigated against Gram-negative (Escherichia coli, Serratia marcescens , and Proteus mirabilis) and Gram-positive (Staphylococcus aureus). The antibacterial activity tests were performed according to agar diffusion method [13] using Cefotaxime (CTX) 30µg, and gentamicin (CN) 10µg as the reference compounds. The sterile cotton swabs were separately dipped into each of the adjusted organism cultures and excess inoculum was removed by pressing and rotating the swab firmly several times against the wall of the tube above the level of the liquid. The swab was streaked all over the surface of the nutrient agar in three dimensions at an angle of 60° to obtain an even distribution of the inoculum.
The plates were then left to dry at room temperature for few minutes. Disks impregnated with DMSO solutions of the compounds under study (75, 150 and 300 µg/disk) were placed on the surface of precultured agar. The plates were then incubated for 24 h at 37ºC and inhibitory zones were recorded.
Structures of all products were confirmed by analytical and spectral methods. IR spectral data showed in general disappearing of (N-H) band and the (C=O) stretching band at (1784, 1674 cm-1). The H 1 -NMR showed dublate in the range δ 6.95-7.98 and δ 6.63 corresponding to C=CH-aromatic ring and C=CH-olifinc ring of both condensation group.
The C 13 -NMR showed 123-134ppm for Aromatic carbon, 133-135ppm for C=CH olifen in malic ring, 162-163ppm for C=O imide and 165-168ppm for C=O carboxylic group. The UV-Visible spectrum of these derivatives showed intense maxima at (256 -276 nm) and (272 -323 nm) which belonged to π→π* and n→π* transitions. The data that give further evidence for the formation of compounds were listed in (table 2).