A new pyrazolo pyrimidine derivative inhibitor of cyclooxygenase-2 with anti-angiogenic activity

Discovery of novel pyrazole and pyrazolo[1,5-a]pyrimidine derivatives as cyclooxygenase inhibitors (COX-1 and COX-2) using molecular modeling simulation

Searching for effective and selective anti-inflammatory agents, our study involved designing and synthesizing new pyrazole and pyrazolo[1,5-a]pyrimidine derivatives 4-11. The structures of the synthesized derivatives were confirmed using different spectroscopic techniques. Virtual screening was achieved for the newly designed derivatives using in silico docking simulation inside the active sites of four proteins classified as two cyclooxygenases (COX)-1 (PDB: 3KK6 and 4OIZ) and two COX-2 (PBD: 1CX2 and 3LN1). Among them, six derivatives 4c, 5b, 6a, 7a, 7b, and 10b displayed the highest binding energy. These derivatives were evaluated for their in vitro COX-1 and COX-2 inhibitory activities and their selectivity indexes were calculated. Additionally, these derivatives displayed IC₅₀ values ranging between 4.909 ± 0.25 and 57.53 ± 2.91 µM, and 3.289 ± 0.14 and 124 ± 5.32 µM, against COX-1 and COX-2, respectively. Furthermore, the tested derivatives were found to have selective inhibitory activity on the COX-2 enzyme. Surprisingly, the two pyrazole derivatives 4c and 5b were found to be the most active, with IC₅₀ values of 9.835 ± 0.50 and 4.909 ± 0.25 µM and 4.597 ± 0.20 and 3.289 ±  0.14 µM compared with meloxicam (1.879 ± 0.1 and 5.409 ±  0.23 µM) and celecoxib (5.439 ± 0.28 and 2.164 ± 0.09 µM) against COX-1/-2, respectively. Besides, two pyrazole derivatives, 4c and 5b, displayed a COX-1/COX-2 SI of 2.14 and 1.49. Computational techniques such as molecular docking, density function theory (DFT) calculation, and chemical absorption, distribution, metabolism, excretion, and toxicity evaluation were applied to explain the molecules' binding mode, chemical nature, drug likeness, and toxicity prediction.

Discovery of New Pyrazolopyridine, Furopyridine, and Pyridine Derivatives as CDK2 Inhibitors: Design, Synthesis, Docking Studies, and Anti-Proliferative Activity

New pyridine, pyrazoloyridine, and furopyridine derivatives substituted with naphthyl and thienyl moieties were designed and synthesized starting from 6-(naphthalen-2-yl)-2-oxo-4-(thiophen-2-yl)-1,2-dihydropyridine-3-carbonitrile (1). The chloro, methoxy, cholroacetoxy, imidazolyl, azide, and arylamino derivatives were prepared to obtain the pyridine-⁻C² functionalized derivatives. The derived pyrazolpyridine-N-glycosides were synthesized via heterocyclization of the C²-thioxopyridine derivative followed by glycosylation using glucose and galactose. The furopyridine derivative 14 and the tricyclic pyrido[3′,2′:4,5]furo[3,2-d]pyrimidine 15 were prepared via heterocyclization of the ester derivative followed by a reaction with formamide. The newly synthesized compounds were evaluated for their ability to in vitro inhibit the CDK2 enzyme. In addition, the cytotoxicity of the compounds was tested against four different human cancer cell lines (HCT-116, MCF-7, HepG2, and A549). The CDK2/cyclin A2 enzyme inhibitory results revealed that pyridone 1, 2-chloro-6-(naphthalen-2-yl)-4-(thiophen-2-yl)nicotinonitrile (4), 6-(naphthalen-2-yl)-4-(thiophen-2-yl)-1H-pyrazolo[3,4-b]pyridin-3-amine (8), S-(3-cyano-6-(naphthaen-2-yl)-4-(thiophen-2-yl)pyridin-2-yl) 2-chloroethanethioate (11), and ethyl 3-amino-6-(naphthalen-2-yl)-4-(thiophen-2-yl)furo[2,3-b]pyridine-2-carboxylate (14) are among the most active inhibitors with IC₅₀ values of 0.57, 0.24, 0.65, 0.50, and 0.93 µM, respectively, compared to roscovitine (IC₅₀ 0.394 μM). Most compounds showed significant inhibition on different human cancer cell lines (HCT-116, MCF-7, HepG2, and A549) with IC₅₀ ranges of 31.3–49.0, 19.3–55.5, 22.7–44.8, and 36.8–70.7 μM, respectively compared to doxorubicin (IC₅₀ 40.0, 64.8, 24.7 and 58.1 µM, respectively). Furthermore, a molecular docking study suggests that most of the target compounds have a similar binding mode as a reference compound in the active site of the CDK2 enzyme. The structural requirements controlling the CDK2 inhibitory activity were determined through the generation of a statistically significant 2D-QSAR model.

Novel pyrazolopyrimidine derivatives targeting COXs and iNOS enzymes; design, synthesis and biological evaluation as potential anti-inflammatory agents

A novel set of 4-substituted-1-phenyl-pyrazolo[3,4-d]pyrimidine and 5-substituted-1-phenyl-pyrazolo[3,4-d]pyrimidin-4-one derivatives were synthesized and evaluated as potential anti-inflammatory agents. The newly prepared compounds were assessed through the examination of their in vitro inhibition of four targets; cyclooxygenases subtypes (COX-1 and COX-2), inducible nitric oxide synthase (iNOS) and nuclear factor kappa B (NF-κB). Compounds 8a, 10c and 13c were the most potent and selective ligands against COX-2 with inhibition percentages of 79.6%, 78.7% and 78.9% at a concentration of 2 μM respectively, while compound 13c significantly inhibited both COX subtypes. On the other hand, fourteen compounds showed high iNOS inhibitory activities with IC50 values in the range of 0.22-8.5μM where the urea derivative 11 was the most active compound with IC50 value of 0.22 μM. Most of the tested compounds were found to be devoid of inhibitory activity against NF-kB. Moreover, almost all compounds were not cytotoxic, (up to 25 μg/ml), against a panel of normal and cancer cell lines. The in silico docking results were in agreement with the in vitro inhibitory activities against COXs and iNOS enzymes. The results of in vivo anti-inflammatory and antinociceptive studies were consistent with that of in vitro studies which confirmed that compounds 8a, 10c and 13c have significant anti-inflammatory and analgesic activities comparable to that of the control, ketorolac. Taken together, dual inhibition of COXs and iNOS with novel pyrazolopyrimidine derivatives is a valid strategy for the development of anti-inflammatory/analgesic agents with the probability of fewer side effects.

Synthesis, Anti-Inflammatory, and Ulcerogenicity Studies of Novel Substituted and Fused Pyrazolo[3,4-d]pyrimidin-4-ones

In the present investigation, some new pyrazolo[3,4-d]pyrimidin-4(5H)-one derivatives (7-12) as well as fused pyrazolo[3',4':4,5]pyrimido[1,2-b]pyridazin-4(1H)-one (14-16) and 7,8,9,10-tetrahydropyrazolo[3',4':4,5]pyrimido[1,2-b]-cinnolin-4(1H)-one (17) ring systems were synthesized using the starting compound 5-amino-6-methyl-1-phenyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one (5). The structures of the newly synthesized compounds were elucidated by IR, (1)H NMR, (13)C NMR, mass spectroscopy, and elemental analysis. The theoretical calculation of their lipophilicity as C log P was performed. The anti-inflammatory activity of all newly synthesized compounds was evaluated using the carrageenan-induced paw edema test in rats using indomethacin as the reference drug. Ulcer indices for the most active compounds were calculated. Seven compounds (10b, 11a-f) showed consistently good anti-inflammatory activity. In particular, 5-{[4-(4-bromophenyl)-3-(4-chlorophenyl)-1,3-thiazol-2(3H)-ylidene]amino}-6-methyl-1-phenyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one (11e) and its 3,4-bis(4-chlorophenyl) analog (11f) were found to be the most effective among the other derivatives, showing activity comparable to that of indomethacin with minimal ulcerogenic effects. Correlation of the biological data of the active compounds with their theoretically calculated C log P values revealed that lipophilicity influences the biological response.

Thioxopyrimidine in Heterocyclic Synthesis I: Synthesis of Some Novel 6-(Heteroatom-substituted)-(thio)pyrimidine Derivatives

A series of novel N-cycloalkanes, morpholine, piperazines, pyrazole, pyrimidine, benzimidazolo[1,2-a]pyrimidine, 1,2,3,4-tetrazolo[1,5-a]pyrimidine, azopyrazolo[1,5- a]pyrimidine, pyrimido[4', 5':3,4]pyrazolo[1,5-a]pyrimidines and pyridine derivatives incorporating a 5-cyano-4-methyl-2-phenyl-(thio)pyrimidine moiety were obtained by the intramolecular cyclization of 6-methylthio-pyrimidine, 6-(benzoylmethyl)thio- pyrimidine and 2-[(5-cyano-4-methyl-2-phenylpyrimidin-6-yl)thio]-3-dimethyl- amino-1-phenyl-prop-2-en-1-one with appropriate amines and enaminone compounds, respectively. The structure of all new synthesized compounds was established from their spectral data, elemental analysis and the X-ray crystal analysis.

Molecular structure, harmonic and anharmonic frequency calculations of 2,4-dichloropyrimidine and 4,6-dichloropyrimidine by HF and density functional methods

Quantum chemical calculations of energies, geometrical structural parameters, harmonic and anharmonic frequencies of 2,4-DCP and 4,6-DCP were carried out by HF and density functional theory methods with 6-311++G(d,p) as basis set. The assignment of each normal mode has been made using the observed and calculated frequencies, their IR and Raman intensities. A detailed interpretation of the FT-IR and FT-Raman spectra of 2,4-DCP and 4,6-DCP was reported on the basis of the calculated potential energy distribution (PED). A comparison of theoretically calculated vibrational frequencies at B3LYP/6-311++G(d,p) with FT-IR and FT-Raman experimental data shows good agreement between them. Natural atomic charges of 2,4-DCP and 4,6-DCP were calculated and compared with pyrimidine molecule.

Synthesis, anti-inflammatory and analgesic activities evaluation of some mono, bi and tricyclic pyrimidine derivatives

3-Aminobenzonitrile and 2-amino-4-phenyl thiazole on condensation with 4-isothiocyanato-4-methyl pentane-2-one gave condensed monocyclic pyrimidine derivatives 1 and 2, 3, respectively. Condensation of 3-aminopropyl imidazole with 3-isothiocyantobutanal gave condensed monocyclic pyrimidine derivative 4. Bicyclic pyrimidine derivatives 5a and 5b have been synthesized by the condensation of diaminomaleonitrile with 4-isothiocyanto-4-methylpentane-2-one and 3-isothiocyanatobutanal, respectively. Condensation of 4-isothiocyanato-4-methyl pentane-2-one with 2,3-diaminopropionic acid hydrochloride yielded another bicyclic compound 7. 4-Isothiocyanato-4-methyl pentane-2-one, 3-isothiocyanatobutanal and 4-isothiocyanatobutan-2-one on condensation with 2-amino-4-nitro phenol gave tricyclic pyrimidine derivatives 8a, 8b and 8c, respectively. Structures of all the synthesized pyrimidine derivatives are supported by correct IR, 1H NMR and mass spectral data. The anti-inflammatory activity evaluation was carried out using carrageenin-induced paw oedema assay, and compounds 1, 3 and 5b exhibited good anti-inflammatory activity, that is, 27.9, 34.5 and 34.3% at 50 mg/kg po, respectively. Analgesic activity evaluation was carried out using phenylquinone writhing assay and compounds 5a, 5b and 8b showed good analgesic activity, that is, 50, 70 and 50% at 50 mg/kg po, respectively.