Synthesis and Cytotoxic Evaluation of Novel 1,2,3‐Triazole‐4‐Linked (2E,6E)‐2‐Benzylidene‐6‐(4‐nitrobenzylidene)cyclohexanones

This work describes the synthesis of novel 1,2,3‐triazole‐4‐linked (2E,6E)‐2‐benzylidene‐6‐(4‐nitrobenzylidene)cyclo‐hexanones starting from cyclohexanone. 1‐(Cyclohex‐1‐en‐1‐yl)piperidine, the enamine from cyclohexanone and piperidine, reacted with 4‐nitrobenzaldehyde to obtain 2‐(4‐nitrobenzylidene)cyclohexanone. Condensation of the latter compound with (prop‐2‐yn‐1‐yloxy)benzaldehyde derivatives under acidic conditions gave (4‐nitrobenzylidene)‐[(prop‐2‐yn‐1‐yloxy)‐benzylidene]cyclohexanones. Finally, ‘click reaction’ of these derivatives and various organic azides led to the title compounds. All compounds were examined by MTT assay for cytotoxic activity in one human breast cancer cell line, MDA‐MB‐231.     

Vibrational assignment, structure and intramolecular hydrogen bond study of 3-amino-1-phenyl-2-buten-1-one

Fourier transform infrared and Fourier transform Raman spectra of 3-amino-1-phenyl-2-buten-1-one and its deuterated analogue were recorded in the regions 400-4,000 and 150-4,000 cm(-1), respectively. Furthermore, the molecular structure and vibrational frequencies of title compound were investigated by a series of density functional theoretical, DFT, and ab initio calculations at the post-Hartree-Fock (MP2) level. Although, the calculated frequencies are generally in agreement with the observed spectra but the DFT results are in much better quantitative agreement with the observed spectra than the MP2 results. The observed wavenumbers were analyzed and assigned to different normal modes of vibration of the molecule. The calculated geometrical parameters show a strong intramolecular hydrogen bond with a N...O distance of 2.621-2.668 A. This bond length is shorter than that of its parent, 4-amino-3-penten-2-one (with two methyl groups in the beta-position), which is in agreement with spectroscopic results. The topological properties of the electron density contributions for intramolecular hydrogen bond in 3-amino-1-phenyl-2-buten-1-one and 4-amino-3-penten-2-one have been analyzed in term of the Bader theory of atoms in molecules (AIM). These results also support the stronger hydrogen bond in the title compound with respect to the parent molecule.     

A molecular orbital rationalization of ligand effects in N2 activation

Molecular orbital theory has been used to study a series of [(micro-N2){ML3}2] complexes as models for dinitrogen activation, with M=Mo, Ta, W, Re and L=NH2, PH2, AsH2, SbH2 and N(BH2)2. The main aims of this study have been to provide a thorough electronic analysis of the complexes and to extend previous work involving molecular orbital analyses. Molecular orbital diagrams have been used to rationalize why for L=NH2 ligand rotation is important for the singlet state but not the triplet, to confirm the effect of ligand pi donation, and to rationalize the importance of the metal d-electron configuration. The outcomes of this study will assist with a more in-depth understanding of the electronic basis for N2 activation and allow clearer predictions to be made about the structure and multiplicity of systems involved in transition-metal catalysis.     

The vibration-rotation emission spectrum of gaseous HZnCl

Gaseous HZnCl has been synthesized for the first time in a high-temperature tube furnace with a dc discharge in a flowing mixture of pure HCl and Zn vapor. The vibration-rotation emission spectrum of HZnCl was recorded at high resolution using a Fourier transform spectrometer. The H-Zn stretching modes (nu(1)) of the H(64)Zn(35)Cl, H(66)Zn(35)Cl, H(68)Zn(35)Cl, and H(64)Zn(37)Cl species, as well as the 2nu(1)-nu(1) hot band of the most abundant isotopologue H(64)Zn(35)Cl, were observed near 1966 cm(-1). A least-squares fit was performed for each of the four observed isotopologues, and their spectroscopic constants were determined.     

Novel 1,2,3,4‐Tetrahydroquinazolinones via Reaction of 2‐Amino‐N‐substituted Benzamides and Dimethyl Acetylenedicarboxylate

Reaction of 2‐amino‐N‐substituted benzamides and dimethyl acetylenedicarboxylate (DMAD) in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in H₂O at room temperature led to the formation of novel 1,2,3,4‐tetrahydroquinazolinones.     

Synthesis and In Vitro Cytotoxic Activity of Novel Triazole‐Isoxazole Derivatives

New derivatives of triazole‐isoxazole were synthesized through a four‐step reaction starting from various ethyl 4‐aryl‐2,4‐dioxobutanoate derivatives. Finally, all compounds were examined by MTT assays for cytotoxic activity in two human breast cancer cell lines (MCF‐7 and T‐47D).     

Prediction of sound velocity and compressibility via molecular simulation at fixed entropy

A molecular-level simulation route is proposed to compute the isentropic thermodynamic properties in a fluid system by Monte Carlo simulation at fixed entropy. The method involves computation of the pressure response of a system to an infinitesimal change in system density by introduction of a single molecule, while retaining the system volume as well as the absolute molar entropy. The probability for accepting a change in temperature during the Monte Carlo moves was weighted against the argument proposed by Smith et al. [W.R. Smith, M. Lísal, I. Nezbeda, Chem. Phys. Lett. 426 (2006) 436–440]. Application to fluid argon has confirmed superior accuracy for the technique within the gas state to yield results within 1.2% of the measured values for the range of thermodynamic conditions investigated.     

Cross-aldol Condensation of Cycloalkanones and Aromatic Aldehydes in the Presence of Nanoporous Silica-based Sulfonic Acid (SiO2-Pr-SO3H) under Solvent Free Conditions

The aromatic aldehydes underwent cross aldol condensation with cycloalkanones in the presence of a catalytic amount of nanoporous silica-based sulfonic acid (SiO2-Pr-SO3H) under solvent-free conditions to afford the corresponding α,α’-bis(substituted benzylidene)cycloalkanones in excellent yields with short reaction time without any side reactions. This method is very general, simple and environmentally friendly in contrast with other existing methods. SiO2-Pr-SO3H was proved to be an efficient heterogeneous solid acid catalyst, which could be easily handled and removed from the reaction mixture by simple filtration, and also recovered and reused without loss of reactivity.     

Nano composite system based on coumarin derivative–titanium dioxide nanoparticles and ionic liquid: Determination of levodopa and carbidopa in human serum and pharmaceutical formulations

The combination of coumarin derivative (7-(1,3-dithiolan-2-yl)-9,10-dihydroxy-6H-benzofuro[3,2-c]chromen-6-on), (DC)–titanium dioxide nanoparticles (TiO₂) and ionic liquid (IL) yields nanostructured electrochemical sensor, formed a novel kind of structurally uniform and electrocatalytic activity material. This new ionic liquid–TiO₂ nanoparticles modified carbon paste electrode (IL–CTP) due to its enhanced conductivity presented very large current response from electroactive substrates. The modified electrode was characterized by different methods including a scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and voltammetry. A pair of well-defined quasi reversible redox peaks of coumarin derivative was obtained at the modified carbon paste electrode (DC/IL–CTP) by direct electron transfer between the coumarin derivative and the CP electrode. Dramatically enhanced electrocatalytic activity was exemplified at the DC/IL–CTP electrode, as an electrochemical sensor to study the electro oxidation of levodopa (LD) and carbidopa (CD). Based on differential pulse voltammetry (DPV), the oxidation of LD and CD exhibited the dynamic range between 0.10– 900.0 μM and 20.0–900.0 μM respectively, and the detection limit (3σ) for LD and CD were 41 nM and 0.38 μM, respectively. DPV was used for simultaneous determination of LD and CD at the DC/IL–CTP electrode, and quantitation of LD and CD in some real samples (such as tablets of Parkin-C Fort and Madopar, Sinemet, water, urine, and human blood serum) by the standard addition method.