Mohamed A. Abdelgawad

Synthesis, cyclooxygenase inhibition, anti-inflammatory evaluation and ulcerogenic liability of novel triarylpyrazoline derivatives as selective COX-2 inhibitors.

A new series of triarylpyrazoline derivatives 8a-p containing the most important COX-2 pharmacophore (SO2CH3 or/and SO2NH2) were synthesized by reaction of propen-1-one derivatives 6a-h with different phenyl hydrazine hydrochloride derivatives 7a-b in aqueous ethanol. All prepared compounds were evaluated for their in vitro COX-1/COX-2 inhibitory activity and the in vivo anti-inflammatory activity. All compounds were more selective for COX-2 isozyme than COX-1 isozyme and showed good in vivo anti-inflammatory activity. Compounds 8g, 8j and 8o showed the highest anti-inflammatory activity and were less ulcerogenic (Ulcer Index=6.85, 7.7, 5.92, respectively) than indomethacin (Ulcer Index=12.3) and comparable to celecoxib (Ulcer Index=4.85).

Synthesis and anticancer activity of some new pyrazolo[3,4-d]pyrimidin-4-one derivatives.

3,6-Dimethyl-1-phenyl-1H-pyrazolo[3,4-d][1,3]oxazin-4-one (3) was prepared by hydrolysis of ethyl 5-amino-3-methyl-1-phenyl-1H-pyrazole-4-carboxylate (1) to afford the corresponding carboxylic acid 2, which was reacted with acetic anhydride to give 3. The pyrazolo[3,4-d][1,3]oxazin-4-one 3 was reacted with hydroxylamine hydrochloride, urea, thiourea, thiosemicarbazide, phenylhydrazine and aromatic amines to afford the corresponding pyrazolo[3,4-d]pyrimidin-4-ones 4, 5a,b, 6, 7, 8a–e, respectively. Condensation of pyrazoloxazine derivative 3 with 99% hydrazine hydrate afforded the 5-aminopyrazolo[3,4-d]pyrimidine derivative 9. Coupling of 9 with aromatic aldehydes yielded a series of 3,6-dimethyl-5-(4-substitutedbenzylideneamino)-1-phenyl-1,5-dihydropyrazolo[3,4-d]pyrimidin-4-ones 10a–e. The new compounds were tested for their antitumor activity on the MCF-7 human breast adenocarcinoma cell line. Almost all the tested compounds revealed antitumor activity, especially 3,6-dimethyl-5-(4-nitrobenzylideneamino)-1-phenyl-1,5-dihydropyrazolo[3,4-d]pyrimidin-4-one (10e) which displayed the most potent inhibitory activity with a half maximal inhibitory concentration (IC50) of 11 µM.

Design, synthesis and biological screening of new 4-thiazolidinone derivatives with promising COX-2 selectivity, anti-inflammatory activity and gastric safety profile

Two series of new thiazolidin-4-one derivatives 4a-c and 8a-e were designed and prepared. All the synthesized compounds were evaluated for their in vitro COX-2 selectivity and anti-inflammatory activity in vivo. Compounds 8c and 8d showed the best overall in vitro COX-2 selectivity (selectivity indexes of 4.56 and 5.68 respectively) and in vivo activities (edema inhibition %=61.8 and 67 after 3h, respectively) in comparison with the reference drug celecoxib (S.I.=7.29, edema inhibition %=60 after 3h). In addition, 8c and 8d were evaluated for their mean effective anti-inflammatory doses (ED50=27.7 and 18.1 μmol/kg respectively, celecoxib ED50=28.2 μmol/kg) and ulcerogenic liability (reduction in ulcerogenic potential versus celecoxib=85%, 92% respectively. Molecular docking studies were performed and the results were in agreement with that obtained from the in vitro COX inhibition assays.

Design, synthesis and antitumor activity of novel pyrazolo[3,4-d]pyrimidine derivatives as EGFR-TK inhibitors.

A novel series of 2-(3,6-dimethyl-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)-N-(4-substitutedbenzylidene)acetohydrazide (12a-g) was prepared and their structures were confirmed by spectral and elemental analyses. The cytotoxic activity of the newly synthesized compounds was evaluated against breast carcinoma (MCF-7), non-small cell lung cancer (A549) and human colorectal adenocarcinoma (HT-29) cell lines using MTT and colony formation assays. The tested compounds showed a marked anticancer activity against all the tested cell lines, especially compound 12g, which was the most potent anticancer agent with half maximal inhibitory concentrations (IC50) between 5.36 and 9.09μM. Docking studies into ATP binding site of EGFR protein tyrosine kinase were performed to predict their scores and mode of binding to amino acids, In addition, the inhibitory activity of the target compounds against epidermal growth factor receptor tyrosine kinase (EGFR-TK) was evaluated. Results indicated the ability of the target compounds to inhibit EGFR-TK with half maximal inhibitory concentrations (IC50) in the range of 4.18-35.88μM. Furthermore, The most active compounds 12g, 12c and 12d were assayed against Fibroblast Growth Factor Receptor (FGFR), Insulin Receptor (IR) and Vascular Endothelial Growth Factor Receptor (VEGFR). The activity of the reported compounds warrants further optimization as novel members in cancer treatment protocols.

Synthesis, Anti-Breast Cancer Activity, and Molecular Modeling of Some Benzothiazole and Benzoxazole Derivatives

A new series of benzothiazoles and benzoxazoles was synthesized using 4‐benzothiazol‐2‐yl‐phenylamine and 4‐benzoxazol‐2‐yl‐phenylamine as starting materials. All the prepared compounds were evaluated for their antitumor activities against human breast cancer cell lines, MCF‐7 and MDA‐231, using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) cell viability analysis. Almost all the tested compounds revealed potent antitumor activity, especially the N‐methyl piperazinyl substituted derivatives 6f and 6c, which displayed the most potent inhibitory activity with IC50 values ranging from 8 to 17 nM. Docking the synthesized compounds into the epidermal growth factor receptor (EGFR), which is highly expressed in breast cancer, was employed to explore the possible interactions of these compounds with the EGFR. The activity of the reported compounds supports its clinical promise as a component of therapeutic strategies for cancer, for which high concentrations of chemotherapeutic agents are always a major limitation.

New benzothiazole/benzoxazole-pyrazole hybrids with potential as COX inhibitors: design, synthesis and anticancer activity evaluation

Ten new hybrids were designed and synthesized, their chemical structures were confirmed through spectral and elemental analysis. The new hybrids were screened against lung, breast and liver cancer cell lines (A549, MCF7 and Hep3B), in addition to normal fibroblast cells. Compound 13a was the most active and selective one on the lung cancer cell line (A549), its IC50 and S.I. values were 2.4 µM and 83.2, respectively. Compound 14b was active on MCF7 with the best selectivity towards this cell line. The new derivatives were screened for their inhibitory activity against COX enzymes, the obtained results revealed that compound 13a and 14b were more active inhibitors for COX-2 than celecoxib. This finding encourages us to consider COX-2 inhibitory activity as a proposed mechanism for their anticancer activity.

Design, Synthesis and Anticancer Screening of Novel Pyrazole DerivativesLinking to Benzimidazole, Benzoxazole and Benzothiazole

Substituted aromatic amines were diazotized followed by coupling with malononitrile to afford substituted phenyl hydrazono-malononitrile compounds 2a-c. Compounds 3a-c were prepared through the reaction of substituted phenyl hydrazono-malononitriles 2a-c with phenyl hydrazine, while the reaction of compounds 2a-c with hydrazine hydrate afforded diamino compounds 4a-c. The diamino compounds 4a-c was condensed with different substituted aromatic aldehydes to yield N-benzylidine pyrazole diamines 5a-i. The structure of the newly synthesized compounds was confirmed by IR, 1H NMR, MS spectral data and elemental analysis. Twelve novel compounds 3a-c and 5a-i were screened for their anticancer activities against breast carcinoma (T47D) and human hepatocarcinoma cell lines (Huh- 7) compared with Doxorubicin. The detailed synthesis, spectroscopic data and anticancer activities of the synthesized compounds were reported.

Design, synthesis and biological evaluation of some novel benzothiazole/benzoxazole and/or benzimidazole derivatives incorporating a pyrazole scaffold as antiproliferative agents

In an aim at developing new antiproliferative agents, new series of benzothiazole/benzoxazole and/or benzimidazole substituted pyrazole derivatives 11a-c, 12a-c and 13a-c were prepared and evaluated for their antiproliferative activity against breast carcinoma (MCF-7) and non-small cell lung cancer (A549) cell lines. The target compound, 2-acetyl-4-[(3-(1H-benzimidazol-2-yl)-phenyl]-hydrazono-5-methyl-2,4-dihydropyrazol-3-one (12a) was the most active compound against both MCF-7 and A549 cell lines with half maximal inhibitory concentrations (IC50)=6.42 and 8.46μM, respectively. Furthermore, the inhibitory activity of the all the target compounds against COX enzymes was recorded as a proposed mechanism for their antiproliferative activity. The obtained results revealed that the benzothiazolopyrazolone derivative 13c was the most potent COX-2 inhibitor (IC50=0.10μM), while the 5-acetylbenzimidazolylpyrazolone derivative 12a was the most COX-2 selective (S.I.=104.67) in comparison with celecoxib (COX-2 IC50=1.11μM, S.I.=13.33). Docking simulation on the most active compounds 12a and 13c had been performed to investigate the binding interaction of these active compounds within the binding site of COX-2 enzyme.Collectively, this work demonstrated the promising activity of the newly designed compounds as leads for further development into antiproliferative agents.

Synthesis and anti-inflammatory evaluation of new 1,3,5-triaryl-4,5-dihydro-1H-pyrazole derivatives possessing an aminosulphonyl pharmacophore

A novel series of 2-pyrazoline derivatives 13a–l was synthesized via aldol condensation of 4-substituted acetophenones with appropriately substituted aldehydes followed by cyclization of the formed chalcones with 4-hydrazinobenzenesulfonamide hydrochloride. The chemical structures of the target pyrazoline derivatives were proved by means of IR, 1H NMR, 13C NMR, mass spectroscopy and elemental analyses data. All the synthesized compounds were evaluated for their cyclooxygenase selectivity, anti-inflammatory and ulcerogenic liability. While compounds 13e, 13h and 13i showed moderate COX-2 selectivity in vitro and good anti-inflammatory activity in vivo, compound 13i showed the highest anti-inflammatory activity that is very close in potency to the reference drug (celecoxib) with better gastric profile than celecoxib.

Design, synthesis, analgesic, anti-inflammatory activity of novel pyrazolones possessing aminosulfonyl pharmacophore as inhibitors of COX-2/5-LOX enzymes: Histopathological and docking studies

A series of newly synthesized 4-aryl-hydrazonopyrazolones were designed and their structures were confirmed by spectral and elemental analyses. All synthesized compounds were evaluated for their in vitro COXs, 5-LOX inhibition, in vivo analgesic and anti-inflammatory activities. Compounds 5d, 5f and 5i were found to be the most potent COX-2/5-LOX inhibitors with superior COX-2 selectivity index values (SI = 5.29-5.69) to reference standard celecoxib (SI = 3.52). Four compounds; 5b, 5c, 5d and 5f showed excellent anti-inflammatory activity (% edema inhibition = 72.72-54.54%) and perfect ED50 values (ED50 = 0.044-0.104 mmol/kg) relative to celecoxib (ED50 = 0.032 mmol/kg). To explore the most active compounds, ulcerogenic effect on stomach in comparison with indomethacin and celecoxib in addition to histopathological investigations were performed. Compound 5f showed better gastric profile (UI = 2.33) than celecoxib (UI = 3.00). Also, 5f caused 50% increase in thermal pain threshold close to reference drug indomethacin (53.13%). Docking study of all the target compounds into COX-2 and 5-LOX active sites was performed to rational their anti-inflammatory activities.