scholarly journals Comparative analysis of the trypanocidal activity and chemical properties of E-lychnophoric acid and its derivatives using theoretical calculations

2005 ◽  
Vol 30 (3) ◽  
pp. 37-45 ◽  
Author(s):  
A. F. C. Alcântara ◽  
D. Silveira ◽  
E. Chiari ◽  
A. B. Oliveira ◽  
J. E. Guimarães ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Geometry Optimization ◽  
Chemical Properties ◽  
Atomic Charge ◽  
Trypanocidal Activity ◽  
Orbital Population ◽  
Theoretical Results ◽  
Conformational Distribution ◽  
And Chemical Properties ◽  
Endocyclic Bond

E-Lychnophoric acid 1, its derivative ester 2 and alcohol 3 killed 100% of trypomastigote blood forms of Trypanosoma cruzi at the concentrations of 13.86, 5.68, and 6.48 µg/mL, respectively. Conformational distribution calculations (AM1) of 1, 2 and 3 gave minimum energies for the conformers a, b, c, and d, which differ from each other only in the cyclononene ring geometry. Calculations (DFT/BLYP/6-31G*) of geometry optimization and chemical properties were performed for conformers of 1, 2, and 3. The theoretical results were numerically compared to the trypanocidal activity. Calculated values of atomic charge, orbital population, and vibrational frequencies showed that the C-4-C-5 pi-endocyclic bond does not affect the trypanocidal activity of the studied compounds. Nevertheless, the structure of the group at C-4 strongly influences the activity. However, the theoretical results indicated that the intra-ring (C-1 and C-9) and pi-exocycle (C-8 and C-14) carbons of caryophyllene-type structures promote the trypanocidal activity of these compounds.

Theoretical calculations of hot-spot initiation in explosives

1968 ◽  
Vol 46 (20) ◽  
pp. 3221-3228 ◽  
Author(s):  
H. J. Bruckman Jr. ◽  
J. E. Guillet
Keyword(s):  
Hot Spots ◽  
Arrhenius Equation ◽  
Theoretical Calculations ◽  
Hot Spot ◽  
Chemical Properties ◽  
Balance Equations ◽  
A Value ◽  
Physical And Chemical ◽  
The Heat Balance ◽  
And Chemical Properties

The heat balance equations for the thermal decomposition of hot spots in explosives have been solved using an iterative computer method. This yields a value of Tc, the critical temperature for hot-spot initiation, which is a function of the size and duration of the hot spot and of the physical and chemical properties of the explosive. It is demonstrated that there is a strong correlation between the ranking of explosives in terms of shock sensitivity and their ranking in terms of Tc. In general explosives having low values of Tc are more sensitive to shock and other forms of accidental initiation than those having high values.Using the computer program, it was shown that the major factor affecting Tc was not the energy released in the explosion, but the rate of decomposition, as expressed in terms of the parameters A and Ea in the Arrhenius equation. Consideration of reagent depletion also indicated certain limits beyond which the heat production cannot be maintained for the time necessary to initiate explosion and insensitivity should result. Considerations of this type could be used to predict safe handling procedures for explosives.

scholarly journals Synthesis and Theoretical Calculations of 2-(p-Tolyl)-2,3-Dihydro-1H-Perimidine using Density Functional Theory

2021 ◽  
Vol 18 (1) ◽  
pp. 75-85
Author(s):  
Vishnu A. Adole ◽  
Ganesh B. Yelmame
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Theoretical Calculations ◽  
Chemical Properties ◽  
Dft Method ◽  
Ring Closure ◽  
Functional Theory ◽  
Spectral Techniques ◽  
And Chemical Properties

In the present study, 2-(p-tolyl)-2,3-dihydro-1H-perimidine (TDHP) is synthesized from 1,8-naphthalenediamine and 4-methylbenzaldehyde by embedding a one-carbon unit between the nitrogen followed by ring closure using green chemistry approach. 1H NMR and 13C NMR spectral techniques were used to validate the structure of the TDHP. The synthesized perimidine TDHP is studied using density functional theory (DFT) to provide valuable insights into structural, chemical, and thermochemical study.The structural and chemical properties of TDHP were computed using the DFT method on the B3LYP/6-311G(d,p) basis package. Bond lengths were predicted from the optimised molecular structure, and the physical and chemical properties of the molecules were inferred as a consequence. The HOMO and LUMO are computed, and quantum chemical parameters are determined using electronic energies. The calculated HOMO-LUMO energy gap is 4.25 eV indicating charge transfer phenomenon within the molecule. The electron density and chemical behaviour of the TDHP was predicted using Mulliken atomic charges and the molecular electrostatic surface potential plot.Amongst all carbon atoms, the C8 carbon as more positive and C27 as more negative carbon atoms. The high global electrophilicity index suggests electrophilic character of the TDHP.The harmonic vibrational frequencies were used to measure total energy, total molar entropy, and molar heat capacity.

scholarly journals Theoretical Prediction of Possible Drug Treatment of COVID-19 using Coumarins Containing Chloroquine Moeity

2020 ◽  
Vol 32 (12) ◽  
pp. 3120-3126
Author(s):  
A.A. Ibrahim ◽  
O.M. Yahya ◽  
M.A. Ibrahim
Keyword(s):  
Theoretical Calculations ◽  
Chemical Properties ◽  
Basis Sets ◽  
Am1 Method ◽  
Hartree Fock ◽  
Physico Chemical ◽  
Coumarin Compound ◽  
Semi Empirical ◽  
Physical And Chemical ◽  
And Chemical Properties

Chloroquine was theoretically reacted with the coumarin compound. Two compounds viz. [N-(7-chloroquinolin-4-yl)-N-(5-(diethylamino)-pentan-2-yl)-4-methyl-2-oxo-2H-chromene-7- sulfonamide] (3) and [N-(7-chloroquinolin-4-yl)-N-(5-(diethylamino)pentan-2-yl)-4-methyl-2-oxo- 2H-chromene-6-sulfonamide] (4) were suggested. The results showed that compound 4 may influence the COVID-19 treatment. The physico-chemical parameters were determined through theoretical calculations by using Hartree-Fock at different basis sets (6-31G), (STO/3G) and the semi-empirical (AM1) method. The calculations demonstrated the scheme of reaction between coumarin and the chloroquine structure by using the predicted mechanisms. The physical and chemical properties of the predicted compounds were determined to select the optimal form as the candidate for COVID-19 treatment. Compound 4 was more stable than compound 3, with different proteins viz. 6YHU, 6YI3 and 6LU7. Three types of software, including Gaussian 03, Chem-Bio office and molecular operating environment (MOE) were employed.

Statistical criteria of stellar population types

1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska
Keyword(s):  
Stellar Population ◽  
Chemical Properties ◽  
Spectrophotometric Study ◽  
Physical And Chemical Properties ◽  
Population Type ◽  
The Galaxy ◽  
Distribution Parameters ◽  
Physical And Chemical ◽  
Statistical Criteria ◽  
And Chemical Properties

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.

The microstructure of a TiB2/Ti-47 Al composite material

1989 ◽  
Vol 47 ◽  
pp. 674-675
Author(s):  
O. Popoola ◽  
A.H. Heuer ◽  
P. Pirouz
Keyword(s):  
Composite Material ◽  
Ion Beam ◽  
Chemical Properties ◽  
Intermetallic Alloys ◽  
Transmission Electron ◽  
Diamond Polishing ◽  
Al Composite ◽  
The Matrix ◽  
Argon Ion ◽  
And Chemical Properties

The addition of fibres or particles (TiB2, SiC etc.) into TiAl intermetallic alloys could increase their toughness without compromising their good high temperature mechanical and chemical properties. This paper briefly discribes the microstructure developed by a TiAl/TiB2 composite material fabricated with the XD™ process and forged at 960°C.The specimens for transmission electron microscopy (TEM) were prepared in the usual way (i.e. diamond polishing and argon ion beam thinning) and examined on a JEOL 4000EX for microstucture and on a Philips 400T equipped with a SiLi detector for microanalyses.The matrix was predominantly γ (TiAl with L10 structure) and α2(TisAl with DO 19 structure) phases with various morphologies shown in figure 1.

Tailoring microstructures of materials through biomimetics

1993 ◽  
Vol 51 ◽  
pp. 500-501
Author(s):  
Mehmet Sarikaya ◽  
Ilhan A. Aksay
Keyword(s):  
Chemical Properties ◽  
Design And Synthesis ◽  
Structure Sensitive ◽  
Macro Scale ◽  
Methods Of Synthesis ◽  
Successive Level ◽  
Engineering Materials ◽  
Physical And Chemical ◽  
And Chemical Properties ◽  
Synthesis Of Materials

Biomimetics involves investigation of structure, function, and methods of synthesis of biological composite materials. The goal is to apply this information to the design and synthesis of materials for engineering applications.Properties of engineering materials are structure sensitive through the whole spectrum of dimensions from nanometer to macro scale. The goal in designing and processing of technological materials, therefore, is to control microstructural evolution at each of these dimensions so as to achieve predictable physical and chemical properties. Control at each successive level of dimension, however, is a major challenge as is the retention of integrity between successive levels. Engineering materials are rarely fabricated to achieve more than a few of the desired properties and the synthesis techniques usually involve high temperature or low pressure conditions that are energy inefficient and environmentally damaging.In contrast to human-made materials, organisms synthesize composites whose intricate structures are more controlled at each scale and hierarchical order.

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