Synthesis, Spectral Study and Theoretical Treatment of 2-(2-(4-bromocyclohexa-1, 3-dienyl)-4-oxo-2H- benz [1, 3] oxazin-3(4H)-ylamino)-2-oxoethyl carbamimidothioate and Derivatives.

The standard heat of formation (ΔHof) and binding energy (ΔEb) for the free compound and their derivatives are calculated by using the PM3 method at 273K of Hyperchem.-8.07 program. The compound is more stable than their derivatives. furthermore to investigate the reactive site of the molecules the electrostatic potential of free derivatives is measured and pm3 is used to evaluate the vibrational spectra of the free derivatives, the frequencies are obtained approximately agreed with those values experimentally found; in addition, the calculation helps to assign clearly the most diagnostic bands .

Исследование механических свойств материалов на основе графена C-=SUB=-62-=/SUB=-H-=SUB=-20-=/SUB=- и полиэтилена (-CH-=SUB=-2-=/SUB=--CH-=SUB=-2-=/SUB=--)-=SUB=-n-=/SUB=-

In the paper, the mechanical properties of the materials based on graphene С62Н20 and polyethylene (-СН2-СН2-)n have been investigated by using semiempirical PM3 method, and the visual models of molecules have been constructed (-СН2-СН2-)n. The calculated values of mechanical parameters show that these materials possess a high elasticity and strength. The orbital energies, potentials of ionization, full energies of electrons, strengths, etc. for given material have been calculated. Opportunity of using these light materials in engineering industry for making of superstrong protective thin coating on car bumpers have been considered. The necessary minimal thickness of protective coating during two cars collision with given mass and speed has been calculated that bumpers do not damage.

Study of the Interaction of Zinc Cation with Azithromycin and its Significance in the COVID-19 Treatment: A Molecular Approach

Introduction: On account of the current COVID-19 pandemic, we have explored the importance of azithromycin and zinc in the treatment of the coronavirus disease by studying the interaction between the cation Zn++ and azithromycin with the tools of the semi-empirical quantum mechanics PM3 method. Methods: By this approach, the niche in which Zn++ is located was determined. Zn++ creates a strong clastic binding between an amine and a hydroxyl group located on the amino-hexose side-chain. Such an interaction serves as a shuttle and allows zinc cation to invade endocellular structures. Results: In this triple collaborative association, the role of hydroxychloroquine would be more that of a chaotropic agent at plasmic membranes, which facilitates access to the azithromycin-Zn++ equipage into key internal compartments. Conclusion: Finally, we show that both azithromycin and Zn++ are susceptible to play a direct role against the replication and the assembly of SARS-CoV-2 particles.

QSAR treatment of meisoindigo derivatives as a potentbreast anticancer agent

A quantitative structure-activity relationship (QSAR) analysis of meisoindigo derivatives as a breast anticancer has been carried out. This study aimed to obtain the best QSAR model in order to design new meisoindigo based compounds with best anticancer activity. The semiempirical PM3 method was used for descriptor calculation. The best QSAR model was built using multilinear regression (MLR) with enter method. It was found that there were 19 new meisoindigo derivativeswith better predictive a potent anticancer agent. The best compound was (E)-2-(1-((3-ethylisoxazol-5-yl)methyl)-2-oxoindolin-3-ylidene)-N-(4-methoxyphenyl)acetamide with the value of IC505.31144 x10-15 (μM).

ANALISIS QSAR SENYAWA TURUNAN MEISOINDIGO SEBAGAI ANTIKANKER PAYUDARA

Quantitative Structure and Relationship (QSAR) of meisoindigo derivative compounds was successfully carried out. The purpose of this study was to find out the best model of meisoindigo derivative compounds as breast anticancer. The research method of this research using the semiempirical PM3 method. The semiempirical method of PM3 was chosen as a better method because it has model results that more represent physicochemical aspects. The selection of the best mathematical model is done by multilinear regression statistical analysis of the calculation data obtained. The results of this study formulate model 5 as the best model with a formula Log 1/IC50 = 44.316 + (-0.0000282*Eis.at) + (-0.257*µ) + (-0.054*LogP) + (0.014*EH) + (-7.241*qC6) + (-1.734*qC9) + (25.711*qO10) + (7.309*qN11) + (94.825*qC13) + (58.794*qO14) + (5.866*qC15)

Chiral Peculiar Properties of Self-Organization of Diphenylalanine Peptide Nanotubes: Modeling Of Structure and Properties

The structure and properties of diphenylalanine peptide nanotubes based on phenylalanine were investigated by various molecular modeling methods. The main approaches were semi-empirical quantum-chemical methods (PM3 and AM1), and molecular mechanical ones. Both the model structures and the structures extracted from their experimental crystallographic databases obtained by X-ray methods were examined. A comparison of optimized model structures and structures obtained by naturally-occurring self-assembly showed their important differences depending on D- and L-chirality. In both the cases, the effect of chirality on the results of self-assembly of diphenylalanine peptide nanotubes was established: peptide nanotubes based on the D-diphenylalanine (D-FF) has high condensation energy E0 in transverse direction and forms thicker and shorter peptide nanotubes bundles, than that based on L-diphenylalanine (L-FF). A topological difference was established: model peptide nanotubes were optimized into structures consisting of rings, while naturally self-assembled peptide nanotubes consisted of helical coils. The latter were different for the original L-FF and D-FF. They formed helix structures in which the chirality sign changes as the level of the macromolecule hierarchy raises. Total energy of the optimal distances between two units are deeper for L-FF (–1.014 eV) then for D-FF (–0.607 eV) for ring models, while for helix coil are approximately the same and have for L-FF (–6.18 eV) and for D-FF (–6.22 eV) by PM3 method; for molecular mechanical methods energy changes are of the order of 2–3 eV for both the cases. A topological transition between a ring and a helix coil of peptide nanotube structures is discussed: self-assembled natural helix structures are more stable and favourable, they have lower energy in optimal configuration as compared with ring models by a value of the order of 1 eV for molecular mechanical methods and 5 eV for PM3 method.

Structural Conformational Study of Eugenol Derivatives Using Semiempirical Methods

We investigated the conformational structure of eugenol and eugenyl acetate under torsional angle effect by performing semiempirical calculations using AM1 and PM3 methods. From these calculations, we have evaluated the strain energy of conformational interconversion. To provide a better estimate of stable conformations, we have plotted the strain energy versus dihedral angle. So, we have determined five geometries of eugenol (three energy minima and two transition states) and three geometries of eugenyl acetate (two energy minima and one transition state). From the molecular orbital calculations, we deduce that the optimized trans form by AM1 method is more reactive than under PM3 method. We can conclude that both methods are efficient. The AM1 method allows us to determine the reactivity and PM3 method to verify the stability.

THE INCLUSION INSIGHT OF –CH3 AND –CH2OH MODIFIED β-CYCLODEXTRINS WITH ONE TRANS-RESVERATROL MOLECULE: A THEORETICAL STUDY

The geometries of the –CH3 and –CH2OH modified β-cyclodextrin {i.e. (β- CD(R) m ( R = –CH3, –CH2OH ; m = 0, 1, …, 7)} and the energetical behaviors of one trans-Resveratrol (TR) molecule including inside their cavities were studied by using ONIOM (B3LYP/6-31G*:PM3) method. The most outstanding geometrical characteristic of the β- CD(R) m is that their inside radius (r) are varied with different chemical modifications. The released energies for one TR molecule passing through or rotating inside the cavities of β- CD(R) m are predicted to be related with the inclusion schemes (from narrow side or wide side of the cavity), the values of the inside radius r, and the types (– CH 3 or – CH 2 OH ) and number (m) of the substituted R groups. Our calculations also suggest that the formation of H-bonds in the inclusion interaction is the main factor to stabilize the formed inclusion complexes, i.e. the TR @β- CD(R) m( R = –CH3, –CH2OH ; m = 0, 1, …, 7).