Design, Synthesis and Biological Evaluation of Spiro Cyclohexane-1,2- Quinazoline Derivatives as Potent Dipeptidyl Peptidase IV Inhibitors.

OBJECTIVE: Inhibition of dipeptidyl peptidase IV (DPP-4) is currently one of the most valuable and potential chemotherapeutic regimes for the medication of Type 2 Diabetes Mellitus (T2DM). METHOD: Based on linagliptin, this study discusses the design, synthesis and biological evaluation of spiro cyclohexane-1,2'-quinazoline scaffold hybridized with various heterocyclic ring systems through different atomic spacers as a highly potent DPP-4 inhibitors. DPP-4 enzyme assay represented that most of the target compounds are 102-103 folds more active than the reference drug linagliptin (IC50: 0.0005-0.0089 nM vs 0.77 nM; respectively). Moreover, in vivo oral hypoglycemic activity assay revealed that most of the tested candidates were more potent than the reference drug, sitagliptin, producing rapid onset with long duration of activity that extends to 24 h. Interestingly, the derivatives 11, 16, 18a and 23 showed evidence of mild cytochrome P450 3A4 (CYP3A4) inhibition (IC50; > 210 µM) and their acute toxicity (LD50) was more than 1.9 gm/kg. Molecular simulation study of the new quinazoline derivatives explained the obtained biological results. CONCLUSION: Finally, we conclude that our target compounds could be highly beneficial for diabetic patients in the clinic.

SYNTHESIS OF NOVEL 1,4,5,6,7,8-HEXAHYDROQUINOLINES OF POTENTIAL ANTIMICROBIAL ACTIVITY.

A number of 2,3-disubstituted-1-cyclohexyl 4-(3,4-dimethoxyphenyl-1,4,5,6,7,8)-hexahydroquinolines and 5-(3,4-dimethoxyphenyl-10-cyclohexyl-3,4,5,6,7,8,9,10-octahydro)-3H-pyrimido[4,5-b]quinolines were synthesized and evaluated for antimicrobial activities. Preliminary results indicated that most compounds tested in this study demonstrated considerable activity against Gram positive, Gram negative bacteria and fungi.

Synthesis, cytotoxic evaluation and molecular docking study of novel quinazoline derivatives as PARP-1 inhibitors.

Novel series of spiro[(2H,3H)-quinazoline-2,1'-cyclohexane] derivatives (I-XVI) were synthesized and biologically evaluated as cytotoxic agents against human breast carcinoma cell lines (MCF-7) using doxorubicin as a reference drug. Most of the tested compounds displayed promising cytotoxic activity, especially derivatives V, VIb and XIb. The most active compounds were docked into the PARP-1 enzyme binding site to predict the ligand-protein binding modes. Lipinski rule of five and ADME profile suggested strongly that compounds V and VIb are promising agents as breast cancer inhibitors with drug likeness approach that have PARP-1 inhibitory activity. The structures of all newly synthesized compounds were confirmed by microanalysis and IR, 1H-NMR and mass spectral data.

A novel class of substituted spiro [quinazoline-2,1'-cyclohexane] derivatives as effective PPAR-1 inhibitors: molecular modeling, synthesis, cytotoxic and enzyme assay evaluation.

Molecular docking simulation study was carried out to design a novel series of spiro [(2H, 3H)quinazoline-2,1'-cyclohexan]-4(1H)-one derivatives as a new class of effective PARP-1 inhibitors. Spiro [2H-3,1-benzoxazine-2,1'-cyclohexan]-4(1H)-one (5) was the starting compound to synthesize the target proposed analogues. The derivatives that showed the top scores and had the best fitting in the binding sites of the target protein were selected to evaluate their in vitro anti-proliferative activity against the cultured human breast carcinoma cell line (MCF-7) using doxorubicin as a standard drug. Additionally, the compounds that exhibited the highest cytotoxic efficiency were further subjected to PARP-1 enzyme assay taking 3-aminobenzamide as the reference drug. The structures of the novel derivatives were confirmed on the bases of microanalytical and spectral data.

Synthesis, biological evaluation and molecular docking of quinazoline-4(1H)-one derivatives as anti-inflammatory and analgesic agents.

Two series of 2-phenyl-4(3H) quinazolinone derivatives have been synthesized. Most of the tested quinazolinone derivatives showed considerable potent anti-inflammatory and analgesic activity of superior GIT safety profile in experimental rats in comparing to indomethacin as reference drug. Compounds VIa, VIb were the most potent anti-inflammatory in experimental rats in comparing to indomethacin as reference drug. Docking study into COX-2 has been made for derivatives of anti-inflammatory activity.

Novel 6,8-dibromo-4(3H)quinazolinone derivatives of anti-bacterial and anti-fungal activities.

Starting from 4-(6,8-dibromo-2-phenyl-4-oxo-(4H)-quinazolin-3-yl)-benzoic acid ethyl ester (II) and its acid hydrazide III, a new series of Schiff bases IV and their cyclized products, thiazolidinones V, oxadiazole VIII, pyrazoles X-XII, pyrroles XIII-XV and other related products were synthesized. These compounds were screened for their anti-bacterial activity against Gram-positive bacteria (Staphylococcus aureus, Legionella monocytogenes and Bacillus cereus) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) and anti-fungal activity (Candida albicans and Aspergillus flavus) using paper disc diffusion technique. The minimum inhibitory concentrations (MICs) of the compounds were also determined by agar streak dilution method. Among the synthesized compounds 2-(4-(2-phenyl-6,8-dibromo-4-oxo-(4H)quinazolin-3-yl)-N-ethylamido benzoic acid hydrazide VIIa was found to exhibits the most potent in vitro anti-microbial activity with the MICs of 1.56, 3.125, 1.56, 25, 25 and 25 microg/ml against E. coli, S. typhimurium, L. monocytogenes, S. aureus, P. aeruginosa, and B. cereus respectively. Compound 2-(4-(2-phenyl-6,8-dibromo-4-oxo-(4H)quinazolin-3-yl)-N-methyl thioamido benzoic acid hydrazide VIIc was found to exhibit the most potent in vitro anti-fungal activity with MICs 0.78 and 0.097 microg/ml against C. albicans and A. flavus.

Synthesis, antitumor activity and molecular docking study of novel sulfonamide-Schiff's bases, thiazolidinones, benzothiazinones and their C-nucleoside derivatives.

A series of sulfapyridine-polyhydroxyalkylidene (or arylidene)-imino derivatives (Schiff's bases) 2a-c and 4a-e were prepared by condensation of 4-amino-N-pyridin-2-ylbenzenesulfonamide (1) with different monosaccharides or with aromatic aldehydes. Treatment of 2a-c with thioglycolic acid led to the formation of the C-nucleosides (3a-c), while treatment of 4a-e with thioglycolic and/or thiosalicylic acids afforded the corresponding 2-arylthiazolidin-4-one or 2-arylbenzothiazin-4-one derivatives 5a-e and/or 6a-e, respectively. Some representative examples of the newly prepared compounds showed considerable cytotoxic effect against breast carcinoma cell line MCF7 and cervix carcinoma cell line HELA in comparison with 5-flurouracil and doxorubicin. AutoDock molecular docking into PTK has been done for lead optimization of the compounds in study as potential PTK inhibitors.

Novel 3-(p-substituted phenyl)-6-bromo-4(3H)-quinazolinone derivatives of promising antiinflammatory and analgesic properties.

A new series of the title compounds incorporated into diverse N and O heterocyclic moieties of pharmacoavailability as anti-inflammatory or analgesic agents, were synthesized starting with 6-bromo-2-phenyl-4H-3,1-benzoxazin-4-one (I) by its fusion with p-aminoacetophenone to give the intermediate compound, 6-bromo-2-phenyl-3-(4-acetylphenyl)-4(3H)quinazolinone (II). The one pot reaction of II with the appropriate aromatic aldehydes and anhyd. ammonium acetate in the presence of either ethyl cyanoacetate or malononitrile afforded the corresponding 2(1H)-pyridone derivatives III or 2(1H)- iminopyridine derivatives IV, respectively, while its reaction with malononitrile and aromatic aldehydes in piperdine gave the 2-aminopyrans V. Also reaction of the acetyl derivative II with different aromatic aldehydes afforded the corresponding 1,3-propen-1-one derivatives VI which underwent cyclization with hydrazines to give the corresponding pyrazoline derivatives VII and with urea or thiourea to give the pyrimidones or pyrimidinethiones VIII. Some representative examples of the new compounds showed promising anti-inflammatory and analgesic activities in experimental animals.

Synthesis and anticancer activity of novel tetralin-6-ylpyridine and tetralin-6-ylpyrimidine derivatives.

A series of tetralin-6-ylpyridines and tetralin-6-ylpyrimidines was newly synthesized starting from 1-(1,2,3,4-tetrahydronaphthalen-6-yl)ethanone (1). The two groups of derivatives incorporated also different five membered nitrogen-containing heterocycles. The anticancer activity of some of the prepared compounds was evaluated using two human tumor cell lines, representing liver and breast. The compounds tested were, in most of cases, selective towards liver cancer, where the most potent compound showed IC50 = 1.01 microg/mL.

Synthesis of some new quinazolin-4-one derivatives and evaluation of their antimicrobial and antiinflammatory effects.

In this work, it was of interest to synthesize new series of some 2-[(E)-2-furan-2-yl-vinyl]-quinazolin-4(3H)-ones incorporated into pyrazoline, isoxazoline, pyrimidine or pyrimidine-thione ring systems at position-3 of the quinazoline ring. The antimicrobial activity and antiinflammatory effect of some of these compounds were studied.