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.     

A Rational Triplic Form for the Exponential

The theory of the power series solution is applied to the Hamburger DE to derive an improper fraction triplic form, E₂ ^N(x), for e^x on the real line. E₂ ^N turns out to be a simpler equivalent to the vertical sequence P₂ ^N of the related Padé table P_M ^N and with comparable summation features.     

Composite Surface Integral Transforms in Neutron Therapy of Cancer

Composite surface finite integral transforms are applied to formulate the optimal ballistic property for a temporally tuned multibeam neutron cancer 3D therapy as a single-valued dynamical system. By invoking Pontryagin's maximum principle, with the operation functions of the beams constituting the control vector, it is proved, in an inverse problem formulation, that for every spatial configuration of the neutron beams, there exists an optimal temporal control vector satisfying an a priori system of linear homogeneous Volterra integral equations of the first kind and convolution type. A version of this newly advanced, temporally optimalized, multibeam 3D irradiation therapy, with a linearized ballistic property, is shown to result from a shooting-type solution to a related, semihomogeneous dual system of linear integral equations of the first kind. A criterion for the controllability of this optimization problem has also been established.     

Synthesis of Some Novel Cyclooctane‐Fused‐Heterocycles with Anticipated Biological Activities

Claisen‐Schmidt condensation of furan‐2‐carboxaldehyde 1 with cyclooctanone 2 afforded smoothly the bischalcone: 2,8‐bis((furan‐2‐yl)methylene)cyclooctanone 3 . Compound 3 was allowed to react with different organic reagents through 1,2 and 1,4 cycloaddition reactions to afford the cyclooctane‐fused heterocyclic compounds 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 and 17a , 17b , 17c in good yields. The structures of all the new compounds were elucidated and deduced from their elemental analyses as well as the spectral data.     

Effect of surface acidity and basicity of aluminas on asphaltene adsorption and oxidation

This study investigates the effect of surface acidity and basicity of aluminas on asphaltene adsorption followed by air oxidation. Equilibrium batch adsorption experiments were conducted at 25°C with solutions of asphaltenes in toluene at concentrations ranging from 100 to 3000 g/L using three conventional alumina adsorbents with different surface acidity. Data were found to better fit to the Freundlich isotherm model showing a multilayer adsorption. Results showed that asphaltene adsorption is strongly affected by the surface acidity, and the adsorption capacities of asphaltenes onto the three aluminas followed the order acidic>basic and neutral. Asphaltenes adsorbed over aluminas were subjected to oxidation in air up to 600°C in a thermogravimetric analyzer to study the catalytic effect of aluminas with different surface acidity. A correlation was found between Freundlich affinity constant (1/n) and the catalytic activity. Basic alumina that has the lowest 1/n value, depicting strongest interactions, has the highest catalytic activity, followed by neutral and acidic aluminas, respectively.     

A combined experimental and theoretical study of the thermal cycloaddition of aryl azides with activated alkenes

Reactions were performed from aryl azides on the one hand, and activated alkenes coming from β-dicarbonyl compounds or malonodinitrile on the other hand, either with recourse to conventional heating or to microwave activation, to afford 1-aryl-1H-1,2,3-triazoles. The mechanism and the regioselectivity of the reactions involving β-dicarbonyl compounds have been theoretically studied using DFT methods at the B3LYP/6-31G* level: they are domino processes comprising a tautomeric equilibrium of the β-dicarbonyl compounds with their enol forms, a 1,3-dipolar cycloaddition of the enol forms with the aryl azides (high activation energy), and a dehydration process (lower activation energy). The effect of non-conventional activation methods on the degradation of 1,2,3-triazolines was next studied experimentally. Finally, some of the 1,2,3-triazoles such synthesized were evaluated for their bactericidal and cytotoxic activities.     

N-aryl pyrazoles: DFT calculations of CH acidity and deprotonative metallation using a combination of lithium and zinc amides

A series of N-aryl and N-heteroaryl pyrazoles have been deproto-metallated using a 2,2,6,6-tetramethylpiperidino-based mixed lithium-zinc combination. Mono-, di-, and tri-iodides have been obtained after subsequent trapping with iodine, depending on the substrate and on the quantity of base used. The results have been discussed in the light of the CH acidities of the substrates, determined both in the gas phase and in THF solution using the DFT B3LYP method.     

A Priority Discrete Queueing Model for Multimedia Multiplexers

Multiplexers have been extensively modeled as discrete time queueing systems. In this article, we model a multimedia multiplexer handling traffic of two classes. One class represents real-time traffic, e.g., packets of live audio or video transmissions, and the other nonreal-time traffic, e.g., packets of file transfer transmissions. These packets arrive into the multiplexer in batches. In each time slot, one batch of each class arrive. The multiplexer gives service priority to class-1 packets over class-2. The demands of each class are in conflict with that of the other, and thus they are treated by the multiplexer differently. The multiplexer is thus modeled as a (preemptive) priority discrete queueing system with simultaneous batch arrivals and geometric service time. The system occupancy is analyzed and the joint probability generating function (PGF) of the number of packets of each class is derived. From this PGF, marginal PGFs of interest are obtained. The results for deterministic service time, most suitable for ATM purposes, are readily obtainable as a special case from the results of this article.