Mohamed Fares

Design, Synthesis and In Vitro Antiproliferative Activity of Novel Isatin‐Quinazoline Hybrids

Using a molecular hybridization approach, a new series of isatin‐quinazoline hybrids 15a–o was designed and synthesized via two different synthetic routes. The target compounds 15a–o were prepared by the reaction of quinazoline hydrazines 12a–e with indoline‐2,3‐diones 13a–c or by treating 4‐chloroquinazoline derivatives 11a–e with isatin hydrazones 14a–c. The in vitro anticancer activity of the newly synthesized hybrids was evaluated against the liver HepG2, breast MCF‐7 and colon HT‐29 cancer cell lines. A distinctive selective growth inhibitory effect was observed towards the HepG2 cancer cell line. Compounds 15b, 15g and 15l displayed the highest potency, with IC50 values ranging from 1.0 ± 0.2 to 2.4 ± 0.4 μM, and they were able to induce apoptosis in HepG2 cells, as evidenced by enhanced expression of the pro‐apoptotic protein Bax and reduced expression of the anti‐apoptotic protein Bcl‐2, in addition to increased caspase‐3 levels.

Amido/ureidosubstituted benzenesulfonamides-isatin conjugates as low nanomolar/subnanomolar inhibitors of the tumor-associated carbonic anhydrase isoform XII

By using a molecular hybridization approach, two series of amido/ureidosubstituted benzenesulfonamides incorporating substituted-isatin moieties were synthesized. The prepared derivatives were in vitro evaluated for their inhibitory activity against human carbonic anhydrase (hCA, EC 4.2.1.1) I, II (cytosolic) and IX, XII (transmembrane, tumor-associated) isoforms. All these isoforms were inhibited in variable degrees by the sulfonamides reported here. hCA I was inhibited with KIs in the range of 7.9-894 nM, hCA II in the range of 7.5-1645 nM (with one compound having a KI > 10 μM); hCA IX in the range of 5.0-240 nM, whereas hCA XII in the range of 0.47-2.83 nM. As all these isoforms are involved in various pathologies, in which their inhibition can be exploited therapeutically, the derivatives reported here may represent interesting extensions to the field of CA inhibitors of the sulfonamide type.

Design, Synthesis and Antitubercular Activity of Certain Nicotinic Acid Hydrazides

Three series of 6-aryl-2-methylnicotinohydrazides 4a–i, N′-arylidene-6-(4-bromophenyl)-2-methylnicotino hydrazides 7a–f, and N′-(un/substituted 2-oxoindolin-3-ylidene)-6-(4-fluorophenyl)-2-methylnicotinohydrazides 8a–c were synthesized and evaluated for their potential in vitro antimycobacterial activity against M. tuberculosis. The results showed that isatin hydrazides 8a–c are remarkably more active than the parent hydrazide 4c. Hydrazides 8b and 8c exhibited the highest activity among all the tested compounds (MIC = 12.5 and 6.25 µg/mL, respectively). Compounds 8b and 8c were also devoid of apparent cytotoxicity to HT-29, PC-3, A549, HepG2 and MCF-7 cancer cell lines. Besides, 8b and 8c showed good drug-likeness scores of 0.62 and 0.41, respectively. Those two isatin hydrazides could offer an excellent framework for future development to obtain more potent antitubercular agents. The SAR study suggested that lipophilicity of the synthesized derivatives is a crucial element that accounts for their antimycobacterial activity. Finally, a theoretical kinetic study was established to predict the ADME of the active derivatives.

Synthesis and cytotoxic activity of biphenylurea derivatives containing indolin-2-one moieties

In our endeavor towards the development of potent anticancer agents, two different sets of biphenylurea-indolinone conjugates, 5a–s and 8a,b were synthesized. The in vitro cytotoxicity of the synthesized compounds was examined in two human cancer cell lines, namely MCF-7 breast cancer and PC-3 prostate cancer cells using the sulforhodamine B (SRB) colorimetric assay. In particular, the MCF-7 cancer cell line was more susceptible to the synthesized compounds. Compound 5o (IC50 = 1.04 ± 0.10 μM) emerged as the most active member in this study against MCF-7, with 7-fold increased activity compared to the reference drug, doxorubicin (IC50 = 7.30 ± 0.84 μM). Compounds 5l, 5q and 8b also exhibited superior cytotoxic activity against MCF-7 with IC50 values of 1.93 ± 0.17, 3.87 ± 0.31 and 4.66 ± 0.42 μM, respectively. All of the tested compounds were filtered according to the Lipinski and Veber rules and all of them passed the filters. Additionally, several ADME descriptors for the synthesized compounds 5a–s and 8a,b were predicted via a theoretical kinetic study performed using the Discovery Studio 2.5 software.

Synthesis, Biological Evaluation and Molecular Docking of Certain Sulfones as Potential Nonazole Antifungal Agents.

We reported herein the synthesis, antifungal activity, docking and in silico ADME prediction studies of four novel series of sulfones 6a–f, 8a–c, 10a–f and 12a–c. All the newly synthesized sulfones were tested against four strains of Candida (including fluconazole-resistant Candida), two strains of Aspergillus, two dermatophytic fungi (Trichophytons mentagrophyte and Microsporum canis) and Syncephalastrum sp. with fluconazole as a reference drug. In general, compounds 8a and 10b showed selective and potent anticandidal activity (MIC: 0.19–0.81 µM) relative to fluconazole (MIC = 1.00 µM). Furthermore, 10e and 12a elicited a remarkable and selective antifungal activity against Aspergillus sp. and the dermatophytic fungi (MIC: 0.16–0.79 µM) relative to fluconazole (MIC: 2–2.6 µM). Moreover, the docking results of the sulfones 6a, 8a, 10a and 10b at the active site of CYT P450 14α-sterol demethylase showed a comparable binding interaction (interaction Energy = −34.87 to −42.43 kcal/mol) with that of fluconazole (IE = −40.37 kcal/mol).

Synthesis of bulky-tailed sulfonamides incorporating pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-1(5H)-yl) moieties and evaluation of their carbonic anhydrases I, II, IV and IX inhibitory effects

Using celecoxib as lead, two novel series of sulfonamides incorporating the pyridotriazolopyrimidine scaffold have been synthesized and evaluated in vitro as inhibitors against four relevant human (h) carbonic anhydrases (CAs, EC 4.2.1.1), the cytosolic and ubiquitous hCA I and II as well as the transmembrane hCA IV and hCA IX. Most of the reported sulfonamides acted as efficient, low micromolar inhibitors of hCAI, II and IV, whereas they displayed higher efficacy in inhibiting the tumor-associated isoform hCA IX. Many derivates herein reported showed better hCA IX versus hCA II selectivity ratios compared to celecoxib or acetazolamide. Considering isoform IX is a validated target for the diagnosis and treatment of hypoxic tumors, discovery of selective CA IX inhibitors represents a promising step to unveil more effective anticancer therapies.

Synthesis, Biological Evaluation and 2D-QSAR Study of Halophenyl Bis-Hydrazones as Antimicrobial and Antitubercular Agents

In continuation of our endeavor towards the development of potent and effective antimicrobial agents, three series of halophenyl bis-hydrazones (14a–n, 16a–d, 17a and 17b) were synthesized and evaluated for their potential antibacterial, antifungal and antimycobacterial activities. These efforts led to the identification of five molecules 14c, 14g, 16b, 17a and 17b (MIC range from 0.12 to 7.81 μg/mL) with broad antimicrobial activity against Mycobacterium tuberculosis; Aspergillus fumigates; Gram positive bacteria, Staphylococcus aureus, Streptococcus pneumonia, and Bacillis subtilis; and Gram negative bacteria, Salmonella typhimurium, Klebsiella pneumonia, and Escherichia coli. Three of the most active compounds, 16b, 17a and 17b, were also devoid of apparent cytotoxicity to lung cancer cell line A549. Amphotericin B and ciprofloxacin were used as references for antifungal and antibacterial screening, while isoniazid and pyrazinamide were used as references for antimycobacterial activity. Furthermore, three Quantitative Structure Activity Relationship (QSAR) models were built to explore the structural requirements controlling the different activities of the prepared bis-hydrazones.

Synthesis, in Vitro and in Silico Studies of Some Novel 5-Nitrofuran-2-yl Hydrazones as Antimicrobial and Antitubercular Agents

In this study, we synthesized two series of novel 5-nitrofuran-2-carbohydrazides 21a-h and 22a-e in addition to a third series of thiophene-2-carbohydrazides 23a-g to develop potent antimicrobial and/or antitubercular agents. The newly synthesized compounds were evaluated in vitro for their antimicrobial and antimycobacterial activities. Most of the 5-nitrofuran-2-carbohydrazides 21a-h and 22a-e displayed variable activity against Aspergillus fumigates, Staphylococcus aureus, Streptococcus pneumonia, Bacillis subtilis, Salmonella typhimurium, Klebsiella pneumonia, Escherichia coli and Mycobacterium tuberculosis. The sulfonamide derivative 21f exhibited superior potency and broad-spectrum antimicrobial activity with minimum inhibitory concentration (MIC)=0.06-0.98 µg/mL and antimycobacterial activity with MIC=3.9 µg/mL. The 5-nitrofuran-2-carbohydrazides 21a, b, g, h and 22a-c exhibited significant antibacterial activity with MIC values in the range of 0.12-7.81 µg/mL. The significances of the 5-nitrofuran moiety and sulfonamide function were explored via the structure-activity relationship (SAR) study. In addition, docking studies revealed that the p-amino benzoic acid (PABA) and binding pockets of the dihydropteroate synthase (DHPS) were successfully occupied by compound 21f. Furthermore, two quantitative structure-activity relationship (QSAR) models were built to explore the structural requirements which controlled the activity.

A Facile Synthesis of Pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidine and Pyrido[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]triazine Bearing a Thiophene Moiety

Pyridinone derivative 8 was synthesized and transformed into the respective chloropyridine 9, which was allowed to react with hydrazine hydrate to afford pyrazolo[3,4-b]pyridin-3-amine derivative 11. Compound 11 was used as a key intermediate for a facile synthesis of the title compounds 14, 15, 17, 21a,b, and 24a–c where the reaction of 11 with some 1,3-dielecrophiles resulted in the formation of pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidines 14, 15, and 17, whereas diazotization of compound 11 gave the respective diazonium salt 18 which was coupled with some active methylene-containing compounds to give the corresponding hydrazones 19a,b and 22a–c. Cyclization of the latter hydrazones yielded the pyrido[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]triazines 21a,b and 24a–c, respectively.

An improved synthesis of pyrido[2,3-d]pyrimidin-4(1H)-ones and their antimicrobial activity

The screening of a small library of diverse chemical structures resulted in the identification of 2-thioxodihydropyrido[2,3-d]pyrimidine 10a as having broad spectrum antibacterial activity (MIC 0.49-3.9 μg mL-1), and reasonable antifungal activity (MIC 31.25 μg mL-1). An expeditious synthesis of 10a was optimized by varying solvents, catalysts and the use of microwave irradiation with the best conditions using DMF as a solvent, I2 (10 mol%) and a 30 minutes reaction time compared to 15 h for classic conventional heating. The pharmacokinetic properties and calculation of drug likeness of 10a suggested good traditional drug-like properties and led to the synthesis of a small library with seven compounds 10a and 10d-i showing broad antimicrobial activity (MIC = 0.49-7.81 μg mL-1) and selectivity indices of more than 5.6 against the normal colon cell line (CCD-33Co). The antifungal activity of compounds 10d-i was moderate to strong with MIC values of 1.95-15.63 μg mL-1.