Synthesis and antimicrobial activity of some new heterocycles incorporating antipyrine moiety

Sc(OTf)3-mediated 1,3-dipolar cycloaddition-ring cleavage-rearrangement: a highly stereoselective access to Z-β-enaminonitriles

A novel and highly stereoselective synthesis of Z-β-enaminonitriles from azides and α,β-unsaturated nitriles is reported. The reaction proceeds via a 1,3-dipolar cycloaddition-ring cleavage-rearrangement cascade mediated by a catalytic amount of Sc(OTf)3. A plausible reaction mechanism for this process is depicted.

Enantioselective synthesis of chiral heterocycles containing both chroman and pyrazolone derivatives catalysed by a chiral squaramide

An efficient chiral squaramide-catalysed enantioselective Michael addition of pyrazolin-5-ones to 3-nitro-2H-chromenes afforded chiral heterocycles containing both chroman and pyrazolone derivatives in high to excellent yields (up to 98%) with high enantioselectivities (up to 96%) under very low catalyst loading (0.2 mol%).

Zinc chloride catalyzed stereoselective construction of spiropyrazolone tetrahydroquinolines via tandem [1,5]-hydride shift/cyclization sequence

A concise synthesis of spiropyrazolones has been developed via an efficient ZnCl₂-catalyzed stereoselective 1,5-hydride shift/cyclization sequence.

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, characterization and anti-breast cancer activity of new 4-aminoantipyrine-based heterocycles

4-Aminoantipyrine was utilized as key intermediate for the synthesis of pyrazolone derivatives bearing biologically active moieties. The newly synthesized compounds were characterized by IR, ¹H- and ¹³C-NMR spectral and microanalytical studies. The compounds were screened as anticancer agents against a human tumor breast cancer cell line MCF7, and the results showed that (Z)-4-((3-amino-5-imino-1-phenyl-1H-pyrazol-4(5H)-ylidene)methylamino)-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 5, 3-(4-bromophenyl) -1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile 13, 1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1-Hpyrazol- 4-yl)-3-(4-iodophenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile 14, 3,3′-(4,4′-sulfonylbis(4,1-phenylene))bis(1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol- 4-yl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile) 16, (Z)-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-hydrazono-4-oxo-3-phenyl-1,2,3,4-tetrahydropyrimidine-5-carbonitrile 17, (Z)-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-oxo-3-phenyl-2-(2-phenylhydrazono)-1,2,3,4-tetrahydro pyrimidine-5-carbonitrile 18, and (Z)-4-(3-amino-6-hydrazono-7-phenyl-6,7-dihydro pyrazolo[3,4-d]pyrimidin-5-yl)-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 19 were the most active compounds with IC₅₀ values ranging from 30.68 to 60.72 μM compared with Doxorubicin as positive control with the IC₅₀ value 71.8 μM.

Synthesis, structure and photoresponsive properties of 4-(3-fluorobenzylideneamino)antipyrine

Organic compounds are attracting greater attention largely in the recent years owing to their potential applications in the functional materials. Herein we reported the structural and photophysical properties of 4-(3-fluorobenzylideneamino)antipyrine. The studied molecule adopts a trans configuration about the imine bond, and forms a non-planar molecular device consisted of two effectively conjugated π-electron moieties. The stronger vibrational and nonlinear optical activities are tightly related to the molecular structural characteristics revealed by the analysis on vibrational modes and frontier molecular orbitals. The intramolecular electrons can be separated by the electron-transporting with specified photon-absorbing theoretically. The total molecular dipole moment, mean linear polarizability and first-order hyperpolarizability calculated at B3LYP/6-31G(d) level are 1.5390 Debye, 35.6075 Å(3) and 1.5391×10(-29) cm(5)/esu, respectively. The reported results indicate that the compound is a promising candidate of photoresponsive materials.

Synthesis, antibacterial and antifungal evaluation of novel 1,4-dihydropyridine derivatives

3,5-Diacetyl-1,4-dihydro-2,4,6-trimethylpyridine (I) has been condensed with aromatic aldehydes to give the corresponding cinnamoyl derivatives IIa-e. the behavior of IIc, d towards thiourea, hydroxylamine hydrochloride, hydrazine hydrate and other bifunctional reagents has been investigated. The newly synthesized compounds were screened for their antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria and as antifungal reagent. Among all the tested compounds, it was found that compounds IIIa and VIIa, b revealed better activity against the Gram-positive rather than the Gram-negative bacteria.

Synthesis and biological evaluation of new benzo-thieno[3,2-d]pyrimidin-4-one sulphonamide thio-derivatives as potential selective cyclooxygenase-2 inhibitors

The aim of this work was to evaluate the potential anti-inflammatory activity of eleven (5-15) new synthesized derivatives of benzo-thieno[3,2-d]pyrimidine on two cell models, namely human keratinocytes NCTC 2544 and mouse monocyte-macrophages J774. For the synthesis of test compounds an efficient approach was developed: the key isothiocyanate was prepared through a simple and ecological method using di-2-pyridyl thionocarbonate (DPT) in substitution of thiophosgene, a highly toxic agent, and the cyclization reaction of benzo-thiosemicarbazide derivates was performed through Wamhoff methods. This procedure can be a new alternative method economically and environmentally advantageous by the simplicity of procedure, reduction of isolation and purification steps, time, costs, and waste production. The potential anti-inflammatory activity of 5-15 was evaluated by determining the expression of cyclooxygenase (COX)-2, inducible NO synthase (iNOS), and intercellular adhesion molecule-1 (ICAM-1), and the release of prostaglandins (PG)E[Formula: see text] and interleukin-8 (IL-8). Our results demonstrate that the compounds 7, 10, 12, 13, 14, and 15 act as a potent inhibitor of COX-2, iNOS, ICAM-1 expression while also suppressing the production of PGE[Formula: see text] and IL-8 in human keratinocytes NCTC 2544 exposed to interferon-gamma (IFN-[Formula: see text]) and histamine and monocyte-macrophages J774 cells treated with lipopolysaccharides (LPS). In conclusion, some derivatives of benzo-thieno[3,2-d]pyrimidine could be developed as a novel class of anti-inflammatory agents.

Synthesis of some new 2-(3-pyridyl)-4,5-disubstituted thiazoles as potent antimicrobial agents

As a part of ongoing studies in developing new potent antimicrobial agents, a series of novel 2-(3-pyridyl)-4,5-disubstituted thiazoles was efficiently synthesized and characterized by spectral and elemental analyses. The newly synthesized compounds were evaluated for their in vitro antimicrobial activity against ten bacterial and five fungal human pathogenic strains using the disc diffusion assay. Among the synthesized compounds, 5-acetyl-4-methyl-2-(3-pyridyl)thiazole (5) exhibited twofold antibacterial activity of ampicillin in inhibiting the growth of Staphylococcus epidermidis (MIC 0.24 μg/mL) and also showed equipotent antifungal activity with amphotricin B against Geotricum candidum (MIC 0.48 μg/mL). From structure-activity relationship (SAR) point of view, increasing the size of the substitutions either at position 4 or 5 on the thiazole nucleus decreased the antimicrobial activity.

Efficient and Convenient Route for the Synthesis of Some New Antipyrinyl Monoazo Dyes: Application to Polyester Fibers and Biological Evaluation

Nine variously substituted azo dye derivatives2–10of antipyrine were prepared. The effects of the nature and orientation of the substituents on the color and dyeing properties of these dyes for polyester fibers were evaluated. The newly synthesized compounds were characterized on the basis of elemental analyses and spectral data. On the other hand, the investigated dyes were applied to polyester fabrics and showed good light, washing, heat, and acid perspiration fastness. The remarkable degree of brightness after washings is indicative of the good penetration and the excellent affinity of these dyes for the fabric. The results in general revealed the efficiency of the prepared compounds as new monoazo disperse dyes. The newly synthesized compounds were screened for their antioxidant and cytotoxic activity against Vitamin C and 5-fluorouracil, respectively. The data showed clearly that most of the compounds exhibited good antioxidant and cytotoxic activities.