Designing and Synthesising Novel Benzophenone Biscyclic Imides Comprising Drug Moity with Investigating their Antimicrobial Activity

: The present work involved designing and synthesizing of a series of new. compounds which their molecules are composed from two biologically active components namely sulfamethoxazole or β-lactam containing drugs and cyclic imides. The target new compounds were synthesized by two steps in the first one a series of six bis ( N- drug phthalamic acid_4-yl) ketone ( 1-6) were prepared from the reaction of sulfamethoxazole or β-lactam containing drugs with benzophenone 3, 3′, 4, 4′ -tetracarboxylic dianhydride. In the second step, compounds (1-6) were introduced in dehydration reaction via fusion process producing the target compounds bis ( N- drug phthalimidyl-4-yl) ketone (7-12). The antibacterial and antifungal high activities of the prepared compounds (7-12) were tested against ( Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas auroginosa and Staphylococcus aurus ) and all compounds showed good to high antibacterial activity. However, the maximum inhibition zone was 38 mm against Staphyloccus aurus , 36 mm against Bacillus subtilis , 35 mm against Pseudomonas auroginosa , 28mm against Klebsiella pneumoniae and 19 mm against Rhizosporium fungi .


Introduction:
Cyclic imides are valuable and important groups in creation of novel pharmaceuticals and bioactive compounds that showed many activities like anti-inflammatory, antitumor, antimicrobial, anticancer and anti-hyperlipidemic activities. In the pharmaceutical industry, cyclic imides are becoming increasingly popular. Cyclic imide structures are seen in several medicinal compounds. Antineoplastic medications include lenalidomide, carmofur, fluorouracil, and aminoglutethimide; antiflu medications include flutamide; and antiepileptic, antiarrhythmic, and sedative-hypnotic medications include phensuximide, phenytoin, and glutethimide [1][2][3][4][5][6][7] . β-Lactam-containing antibiotics are still one of the most important antibiotics 8 that used in treatment of a wide range of different infections. Cefotaxime, ampicillin and amoxicillin are examples for pharmacologically active β-lactam antibiotics used for treatment and prevention of gastrointestinal, skin bacterial and urinary infections 9-12 . In the light of all these facts beside increasing the problem of multidrug resistant micro-organisms and the urgent need for new antibiotics used in treatment of different bacterial and fungal infections, we thought it is very valuable to design and synthesize new developed β-lactams via incorporation of imide cycles in cefotaxime, ampicillin, amoxicillin, cifixime and cephalexin molecules followed by their antimicrobial activity screening. The work involved also incorporation of the well known sulfa drug (sulfamethoxazole) which contain sulfonamide skeleton [13][14][15][16] with cyclic imide in the same molecule and the resulted compound and the other new target β-lactam compounds are anticipated have quite big antimicrobial since theyʹve been involved composed from two biologically energetic segments. In this study, a number of drugs were developed by incorporating imide rings into its composition, which resulted in new compounds with high antibacterial and anti-fungal efficacy.

Materials and Methodologies:
Melting points of the synthesized compounds were determined by Gallen kamp melting point apparatus and were uncorrected. FTIR spectra were recorded as KBr disc on Shimadzu FTIR-8400 Fourier Transform Infrared Spectrophotometer while 1 H-NMR and 13 C-NMR spectra were recorded on Bruker Bio Spin apparatus, GmbH.

Method:
Synthesis of bis (N-drug phthalamic acid-4-yl) ketone (1-6) The titled compounds were synthesized according to literature procedures 17,18 with minor modifications. The solution of β-lactam containing drug (amoxicillin, ampicillin, cefotaxime, cifixime, cephalexin) 0.02 mole or sulfamethoxazole in dry acetone 30mL was added dropwise to the solution of benzophenone 3, 3′, 4, 4′-tetracarboxylic dianhydride 0.01mol, 3.229 g in dry acetone (25mL) with stirring and cooling at 0-5 ℃. After completion of addition the mixture was stirred for 3 hours at room temperature then the formed precipitate was filtered, washed with ether, dried and finally purified by recrystallization from a suitable solvent.

Synthesis of bis (N-drug phthalimide -4-yl) ketone (7-12)
The titled compounds were synthesized via dehydration of compounds (1-6) by fusion method 18 . Compounds (1-6), 1.0 g of was heated in oil bath until complete fusion then oil bath temperature was raised to ten degrees above melting point value of the used compound for additional 3 hours. Finally the product was left at room temperature and the resulted solid was purified by recrystallization from a suitable solvent.

Biological activity
The antimicrobial activity of several of the newly synthesized cyclic imides was tested using the agar diffusion technique using cap plates and incubation at 37 ℃ for 24 hours 19 , with the inhibition zone quantified in micrometers.

Results and Discussion:
Research has been directed towards preparing new biologically active compounds. Thus, by combining two imide cycles with sulfamethoxazole or β-lactam containing medicinal molecules, novel pharmacological combinations can be produced that, by their antibacterial action, can help to solve the problem of multidrug resistant microorganisms.
In order to perform this target in the begining was choose many drugs including (sulfamethaxole, amoxycillin, ampicillin, cefotaxime, cefixim and cephalexin) which contain amino group ready for introducing in reaction with cyclic anhydride producing bis(N-drug phthalamic acid 4-4ʹ) ketone (1-6). In the second step compounds amic acid (1-6) were introduced in dehydration reaction by using fusion method 18 .
During fusion process bis amic molecules (1-6) lose two water molecules followed by ring closure leading to bis cyclic imides formation (7-12) 18 . These steps are indicated in Scheme .1. On the other hand, 1 H-NMR spectrum of imide compounds (7,9,12) showed indication at (δ=2.1-2.75) ppm, (δ=6.72-8.52) ppm and (δ=8.1-9.77) ppm which belong to methyl group protons, aromatic protons and (N-H) protons respectively. The spectra of compounds (7) and (9) showed indication at (δ=4.21-4.85) ppm which belong to the protons in lactam ring while the spectra of compounds (9) and (12) showed indication at (δ=6.1-6.24) ppm belong to vinylic protons. All details of 1 H-NMR spectrum data for imides (7,9,12) are shown in Tab.7 and Fig. 3.         Biological Activity study Biological activity study in this work involved evaluation of antibacterial activity of compounds (7)(8)(9)(10)(11)(12) against several types of bacteria including Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas auroginosa and Staphylococcus aurus bacteria and evaluation of antifungal activity of the same compounds against Rhizosporium fungi. Inhibition zones in (mm) caused by the new compounds (7-12) against the tested organisms (bacteria and fungi) are shown in Tab. 8 and these results compounds (7, 10 and 11) have been identified showed a high level of activity against Pseudomonas auroginosa while compound (12) showed very high activity and compounds (8 and 9) showed moderate regulation against this bacterium. The compounds (9, 10 and 12) exhibited very high regulation against Staphylococcus aurus because the ability of some of these compounds to dissolve the fatty layer of this wall bacteria, which causes cell fluids to drain out and destroy them. The possibility of forming hydrogen bonds between hydroxyl groups, N and S in compounds and water molecules in the cell, which is 80-90% of the cell weight, and this leads to disruption of vital activities cell and destroy it, because the compound kills microorganisms or inhibits their growth by damaging or preventing their formation cell walls or through a defect in the permeability of the cytoplasmic membranes and the physical and chemical structure of protein and nucleic acids in the cell by imbalance in cellular enzymatic activity as well as by preventing protein synthesis and nucleic acids the resistance to any type of bacteria varies its genera of chemical compounds results from the presence of a thick envelope surrounding the cell because it contains a high percentage of fat, which prevents these substances from entering the cell.
Compound (12) showed very high activity against Bacillus subtilis and high activity against Klebsiella pneumoniae while compounds (7, 9, 10 and 11) exhibited high activity against these two types bacteria. Finally Compound (8) showed high activity against Bacillus subtilis bacteria.
On the other hand, the results in Tab .8 indicated that the new compounds (7, 9, 10, 11 and 12) showed high antifungal activity while compound (8) showed moderate activity against the tested fungi.

Conclusion:
In this work were study the changes in various physical properties for Prepared compounds. The properties studied by FTIR, 1 H-NMR and 13 C-NMR spectroscopies. Development was made in some drug molecules through introducing biscyclic imides moieties in original drug molecule. Introducing of these moieties increased antibacterial and antifungal activity of the resulted molecules, thus most of them showed very high antibacterial antifungal activity. These promising results can lead to find new drugs which may fight different bacterial infections.