Hatem A. Abdel-Aziz

Synthesis and antimicrobial evaluation of 1-(benzofuran-2-yl)-4-nitro-3-arylbutan-1-ones and 3-(benzofuran-2-yl)-4,5-dihydro-5-aryl-1-[4-(aryl)-1, 3-thiazol-2-yl]-1H-pyrazoles

2-Acetylbenzofuran 1 on treatment with substituted aldehydes affords the corresponding chalcones 2a-c. Treatment of the chalcones with nitromethane under Michael addition condition furnished the corresponding Michael adducts 3a-c. Cyclocondensation of the chalcones 2a and 2b with thiosemicarbazide under basic refluxing conditions gave 3-(benzofuran-2-yl)-5-(4-aryl)-4,5-dihydropyrazole-1-carbothioamides 4a,b. The pyrazolines 7a-d were synthesized by treating 4a,b with phenacyl bromides in refluxing ethanol. All the synthesized compounds were screened for their antibacterial and antifungal activities at 100 microg concentration. Some of our compounds showed excellent antimicrobial activities than control drugs.

Nanomolar detection of hypochlorite by a rhodamine-based chiral hydrazide in absolute aqueous media: application in tap water analysis with live-cell imaging.

By employing the oxidation property of hypochlorite (OCl(-)), a novel rhodamine-based hydrazide of the chiral acid ((S)-(-)-2-pyrrolidone-5-carboxylic acid) (RHHP) was designed and synthesized for detection of OCl(-) absolutely in aqueous medium at nanomolar level. The structure of the chiral sensor was also proved by the X-ray crystallography. The bioactivity and the application of the probe for detection of OCl(-) in natural water system have been demonstrated. A plausible mechanism for oxidation of the sensor followed by hydrolysis is also proposed. The sensibility of the receptor toward OCl(-) was studied in absolute aqueous media, and the detection limit of hypochlorite-mediated oxidation to the receptor in nanomolar level makes this platform (RHHP) an ultrasensitive and unique system for OCl(-) oxidation.

Microwave-assisted synthesis and in-vitro anti-tumor activity of 1,3,4-triaryl-5-N-arylpyrazole-carboxamides

Regioselective 1,3-dipolar cycloaddition of nitrilimines with 5-arylidene-2-arylimino-4-thiazolidinones and with 2-(4-arylidene)thiazolo[3,2-a]benzimidazol-3(2H)-ones afforded the corresponding 1,3,4-triaryl-5-N-arylpyrazole-carboxamides and pyrazolylbenzimidazoles. All reactions were carried out under conventional thermal heating and/or microwave irradiation. Both the pyrazole-5-carboxamides and pyrazolylbenzimidazoles were examined for their in-vitro anti-tumor activities against two tumor cell lines, Hep-2 and colon CaCo-2. Most of the obtained compounds exhibited significant activity against CaCo-2 and Hep-2 cell lines.

Convenient synthesis and antimicrobial evaluation of some novel 2-substituted-3-methylbenzofuran derivatives

The reaction of 3-methylbenzofuran-2-carbohydrazide (1) with l-phenyl-2-bromoethanone (2a) or 2-chloro-1-(4-chlorophenyl)ethanone (2b) afforded (Z)-1,2-di[(3-methylbenzofuran-2-carbohydrazido]-1-arylethenes 5a and 5b, respectively. Single crystal X-ray analyses of compound 5a proved that the reaction proceeds in 2:1 molar ratio and ruled out the other possible structures 1,3,4-oxadiazine derivative 6 or E-isomer 7. Furthermore, both of 3-(3-methylbenzofuran-2-yl)-3-oxopropanenitrile (9) and 3-methyl-2-benzofuranoyl chloride (15) were used as starting materials for the synthesis of several compounds, such as pyrazoles 10 and 14, oxime 11, hydrazones 12a, b and 3,1-bezoxazine 19. The newly synthesized compounds were tested for their antimicrobial activity against five fungal species and four bacterial species also their minimum inhibitory concentration (MIC) against most of test organisms was performed. Some of these compounds exhibited a significant antimicrobial activity.

Convenient Synthesis and Antimicrobial Activity of New 3-Substituted 5-(Benzofuran-2-yl)-pyrazole Derivatives

The reaction of ethyl 4‐(benzofuran‐2‐yl)‐2,4‐dioxobutanoate 2 with two moles of hydrazine hydrate afforded 5‐(benzofuran‐2‐yl)‐1H‐pyrazole‐3‐carbohydrazide 4a, while its reaction with equimolar amount of phenylhydrazine gave ester 3b which then converted to 5‐(benzofuran‐2‐yl)‐1‐phenyl‐1H‐pyrazole‐3‐carbohydrazide 4b. Various new compounds such as imides 5 and 6, acyl hydrazones 7 and 8, bi‐pyrazoles 9‐12, and 1,3‐thiazole derivatives 14 and 15 were prepared from carbohydrazide derivatives 4a, b. The new compounds are tested for their antimicrobial activity. Compounds 2, 5, 7, and 8 showed antifungal activities against C. albicans. Also, compounds 2, 6, 8, and 15 showed antibacterial activities.

Stereoselective synthesis and antimicrobial activity of benzofuran-based (1E)-1-(piperidin-1-yl)-N2-arylamidrazones

The reaction of 2-oxo-N-arylpropanehydrazonoyl chlorides 3a-e with 3-methyl-2-benzofurancarboxylic acid hydrazide (7) furnished N-(aryl)propanehydrazonoyl chlorides 8a-e. X-Ray of 8c revealed the (1Z,2E) configuration of structure 8. Nucleophilic substitution reaction of 8a or 8d with piperidine resulted in the formation of 1-(piperidin-1-yl)-N(2)-arylamidrazones 9a, b. The X-ray diffraction of 9b showed its (1E,2E) configuration and it confirmed the stereoselectivity of the latter reaction. (1E,2Z,3E)-1-(Piperidin-1-yl)-1-(arylhydrazono)-2-[(3-methylbenzofuran-2-oyl)hydrazono]-4-arylbut-3-enes 11 were synthesized in stereoselective reaction from 8 or alternatively from 9. X-ray analysis of 11b showed a conversion of configuration respect to 8d or 9b. X-Ray analysis of 9b and 11b revealed the role of hydrogen interactions in the stereochemistry of their solid state structure. The in vitro antimicrobial activity of the newly synthesized compounds demonstrated an excellent growth inhibition of compounds 9 and 11 against clinically isolated strains of human fungal pathogens and exhibited a significant potency against gram-positive bacteria. Griseofulvin and Amoxicilline were used as references for antifungal and antibacterial screening. The effect of most potent antifungal compound 9b on morphological features of Aspergillus fumigatus and Candida albicans using image analyzer was studied. Furthermore, the effect of 9b on the ultra-structures of the latter fungi was occurred by transmission electron microscope.

Carbonic anhydrase inhibitors: Benzenesulfonamides incorporating cyanoacrylamide moieties are low nanomolar/subnanomolar inhibitors of the tumor-associated isoforms IX and XII

A series of benzenesulfonamides incorporating cyanoacrylamide moieties (tyrphostine analogues) have been obtained by reaction of sulfanilamide with ethylcyanoacetate followed by condensation with aromatic/heterocyclic aldehydes, isothiocyanates or diazonium salts. The new compounds have been investigated as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4. 2.1.1), and more specifically against the cytosolic human (h) isoforms hCA I and II, as well as the transmembrane, tumor-associated ones CA IX and XII, which are validated antitumor targets. Most of the new benzenesulfonamides were low nanomolar or subnanomolar CA IX/XII inhibitors whereas they were less effective as inhibitors of CA I and II. The structure-activity relationship for this class of effective CA inhibitors is also discussed. Generally, electron donating groups in the starting aldehyde reagent favored CA IX and XII inhibition, whereas halogeno, methoxy and dimethylamino moieties led to very potent CA XII inhibitors.

Design, synthesis and QSAR study of certain isatin-pyridine hybrids as potential anti-proliferative agents.

A hybrid pharmacophore approach was adopted to design and synthesize new series of isatin-pyridine hybrids. All the newly prepared hybrids (5a-o, 8 and 11a-d) were in vitro evaluated for their anti-proliferative activity against three human cancer cell lines, namely HepG2 hepatocellular carcinoma, A549 lung cancer and MCF-7 breast cancer. Compound 8 emerged as the most active member against HepG2 cell line (IC50 = 2.5 ± 0.39 μM), with 2.7-fold increased activity than the reference drug, doxorubicin (IC50 = 6.9 ± 2.05 μM). Whilst, compound 11c was found to be the most potent counterpart against A549 and MCF-7 cell lines with IC50 values of 10.8 ± 1.15 and 6.3 ± 0.79, respectively. The weightiness of the utilization of non-cleavable linker, as the chalcone linker, and simplification of the first group, was explored via the SAR study. Furthermore, a QSAR model was built to explore the structural requirements controlling the cytotoxic activities. Notably, the predicted activities by the QSAR model were very close to those experimentally observed, hinting that this model could be safely applied for prediction of more efficacious hits comprising the same skeletal framework. Finally, a theoretical kinetic study was established to predict the ADME of the active hybrids.

Isatin-pyrazole benzenesulfonamide hybrids potently inhibit tumor-associated carbonic anhydrase isoforms IX and XII

New series of benzenesulfonamide derivatives incorporating pyrazole and isatin moieties were prepared using celecoxib as lead molecule. Biological evaluation of the target compounds was performed against the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) and more precisely against the human isoforms hCA I, II (cytosolic), IX and XII (transmembrane, tumor-associated enzymes). Most of the tested compounds efficiently inhibited hCA I, II and IX, with KIs of 2.5-102 nM, being more effective than the reference drug acetazolamide. Compounds 11e, 11f, 16e and 16f were found to inhibit hCA XII with Ki of 3.7, 6.5, 5.4 and 7.2 nM, respectively. Compounds 11e and 16e, with 5-NO2 substitution on the isatin ring, were found to be selective inhibitors of hCA IX and hCA XII. Docking studies revealed that the NO2 group of both compounds participate in interactions with Asp132 within the hCA IX active site, and with residues Lys67 and Asp130 in hCA XII, respectively.

Facile synthesis and in-vitro antitumor activity of some pyrazolo[3,4-b]pyridines and pyrazolo[1,5-a]pyrimidines linked to a thiazolo[3,2-a]benzimidazole moiety.

The key precursor E‐3‐(N,N‐dimethylamino)‐1‐(3‐methylthiazolo[3,2‐a]benzimidazol‐2‐yl)prop‐2‐en‐1‐one 4 was synthesized in good yield using Golds reagent. The reaction of enaminone 4 with 5‐amino‐3‐aryl‐1‐phenylpyrazoles 5a, b in refluxing acetic acid in the presence of sulphuric acid, yielded pyrazolo[3,4‐b]pyridines 7a, b. Similarly, pyrazolo[1,5‐a]pyrimidines 10a, b and 14a–f were prepared by reaction of enaminone 4 with 5‐amino‐1H‐pyrazoles 8a, b and 12a–f, respectively. The structure of pyrazolo[1,5‐a]pyrimidine 10b was determined by X‐ray diffraction. The synthesized compounds were tested for their in‐vitro antitumor activity against the colon cancer cell line CaCo‐2; their cytotoxicity against the normal fibroblast cell line BHK was explored as well. Some of the tested compounds exhibited cell growth inhibitory activity. The significant antitumor activity of compound 14f against the CaCo‐2 cell line (IC50 = 0.5 μg/mL) was coupled with a lower toxicity against BHK (IC50 = 2.3 μg/mL).