Photosonochemical catalytic ring opening of α-epoxyketones

The combination of ultrasound and photochemical methods has been used for the catalytic ring opening of α-epoxyketones by 1-benzyl-2,4,6-triphenylpyridinium tetrafluoroborate (NBTPT) as photocatalyst in methanol. Sonication of these compounds in the presence of NBTPT did not result in the opening of epoxide ring, but the use of ultrasound increased the rate of photoreaction

Synthesis of Some New Unsymmetrically Substituted 1,4-Dihydropyridines

A series of some new 3,5-unsymmetrically substituted 1,4-dihydropyridines have been synthesized, which have ethoxycarbonyl and acetyl groups on 3-and 5-positions, respectively. A three-step procedure has been examined to increase the yield of the desired products, by suppressing the formation of the symmetrically substituted 3,5-diacetyl-1,4-dihydropyridines and 3,5-diethoxycarbonyl-1,4-dihydropyridines

Nucleophilic ability of 5-aminopyrazoles in the multicomponent synthesis of pyrazolodihydropyridines and pyrazolodihydropyrimidines

The nucleophilic ability of substituted 5-aminopyrazoles and the type of dicarbonyl component were investigated to synthesise various pyrazolodihydropyridines and pyrazolodihydropyrimidines. In this multicomponent reaction, two possible reaction mechanisms are proposed to elucidate the importance of the nucleophilic positions in the 5-aminopyrazole molecule leading to the different cyclocondensation products. The extent of the nucleophilicity of the C4-position (β-position of the enamine moiety), the lone pairs of the N1-atom and the NH2 group in the pyrazole molecule affect the reaction time and type of product formed. The acidity of the CH2 moiety of the β-dicarbonyl compound may affect the type of product formed. 1H and 13C NMR data and the X-ray crystal structure analysis support the experimental work and the formed product type. Keywords: 5-Aminopyrazoles, cyclocondensation, Knoevenagel condensation, multicomponent reactions, Nucleophilic ability, pyrazolodihydropyridines, pyrazolodihydropyrimidines

Synthesis, Molecular Modelling and Biological Studies of 3-hydroxy-pyrane-4-one and 3-hydroxy-pyridine-4-one Derivatives as HIV-1 Integrase Inhibitors

Background: Despite the progress in the discovery of antiretroviral compounds for treating HIV-1 infection by targeting HIV integrase (IN), a promising and well-known drug target against HIV-1, there is a growing need to increase the armamentarium against HIV, for avoiding the drug resistance issue. Objective: To develop novel HIV-1 IN inhibitors, a series of 3-hydroxy-pyrane-4-one (HP) and 3- hydroxy-pyridine-4-one (HPO) derivatives have been rationally designed and synthesized. Methods: To provide a significant characterization of the novel compounds, in-depth computational analysis was performed using a novel HIV-1 IN/DNA binary 3D-model for investigating the binding mode of the newly conceived molecules in complex with IN. The 3D-model was generated using the proto-type foamy virus (PFV) DNA as a structural template, positioning the viral polydesoxyribonucleic chain into the HIV-1 IN homology model. Moreover, a series of in vitro tests were performed including HIV-1 activity inhibition, HIV-1 IN activity inhibition, HIV-1 IN strand transfer activity inhibition and cellular toxicity. Results: Bioassay results indicated that most of HP analogues including HPa, HPb, HPc, HPd, HPe and HPg, showed favorable inhibitory activities against HIV-1-IN in the low micromolar range. Particularly halogenated derivatives (HPb and HPd) offered the best biological activities in terms of reduced toxicity and optimum inhibitory activities against HIV-1 IN and HIV-1 in cell culture. Conclusion: Halogenated derivatives, HPb and HPd, displayed the most promising anti-HIV profile, paving the way to the optimization of the presented scaffolds for developing new effective antiviral agents