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Theoretical study of new pyranoquinoxaline, pyrimido (pyrido) pyranoquinoxaline and quinoxalinone derivatives

Castro E. A., Moustafa O. S.

Bulletin of the Polish Academy of Sciences. Chemistry

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2003

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Vol. 51, No. 1

59-69

EN

We present the results of structural theoretical calculations made with the Molecular Mechanics method for a series of new pyranoquinoxaline, pyrimido (pyrido) pyranoquinoxaline and quinoxalinone derivatives which have been recently synthetized. The different contributions to the steric energy are analysed for the new 19 molecules, some particular structural features are discussed and some possible extensions are pointed out.

2

An Optimal Characterization of Structure by Means of several Molecular Connectivity and Complexity Indices

Marinich J., Maguna F., Okulik N., Castro E. A.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 4

589-600

EN

(Received April 9th, 2001; revised manuscript November 21st, 2001) An improved numerical procedure is presented in order to enhance the possibilities of fitting polynomial equations to predict log P data within the realm of the QSAR/QSPR theory. The use of real exponents instead of restricting to integer ones for the variables in the mathematical equations gives better results and a minor number of independent variables are needed to achieve a given accuracy degree. Some possible future extensions of the method are pointed out.

3

Application of quantitative structure-retention relationships to calculate chromatographic retention times of o-acethylphenyl esters

Romanelli G. P., Jios J., Autino J. C., Cafferata L. F. R., Ruiz D., Castro E. A.

Chemia Analityczna

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2002

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Vol. 47, No. 2

205-217

EN

The quantitative structure-retention relationships theory is applied to compute retention times of some o-acetylphenyl esters. Molecular topological descriptors are used to calculate the fitting equations. Experimental data is satisfactorily described by the theoretical equations. Some further possible extensions of the present approach are analyzed for future developments.

PL

Teorię ilościowych zależności struktura- retencja zastosowano do obliczenia czasów retencji pewnych estrów o-acetylofenylowych. Do obliczenia równań dopasowania zastosowano topologiczne deskryptory cząsteczkowe. Równania teoretyczne satysfakcjonujące opisują dane doświadczalne. Przeanalizowano możliwości rozwinięcia obecnych badań w przyszłości.

4

Conformational analysis of 1,2,4,5-tetroxane

Jorge N., Gómez-Vara M., Romero J. R., Castro E. A.

Bulletin of the Polish Academy of Sciences. Chemistry

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2002

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Vol. 50, No. 3

387-395

EN

Different theoretical procedures are applied to make a conformational study of the 1,2,4,5-tetroxane molecule: AMI semi-empirical method, ab initio RHF method at the 3-21+G and 6-311+G(d,p) basis set levels and B3LYP density functional method at the same basis set levels. The molecular stability is analyzed on the basis of different stereo-electronic and symmetry features. There is a general agreement between these methods and all of them predict the chair conformation to be the most stable conformer.

5

Density functional analysis of the trans isomers of 3,6-diphenyl-1,2,4,5-tetroxane molecule

Jorge N., Castro E. A., Cafferata L. F. R., Gomez Vara M. E.

Bulletin of the Polish Academy of Sciences. Chemistry

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2001

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Vol. 49, No. 3

255-260

EN

We present the results of theoretical calculations of 3,6-diphenyl-1,2,4,5-tetroxane molecule derived from AMI and PM3 semiempirical methods and B3LYP Density Functional Study procedure in order to determine the relative stabilities of the different isomers. In order to analyze the main factors contributing to the corresponding stabilities we resort to stereoelectronic effects as well as to steric factors. Theoretical predictions are compared with available experimental data and some disagreements are found.