Wyniki wyszukiwania - Biblioteka Nauki

1

IR and 1H NMR spectral studies of some 2-Amino-4-isopropyl-6-methoxy-N-phenylpyrimidine-5-carboxamides: Assessment of substituent effects

100%

Arulkumaran R. , Sundararajan R. , Manikandan V. , Sathiyendiran V. , Pazhamalai S. , Thirunarayanan G.

International Letters of Chemistry, Physics and Astronomy

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2014

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tom Vol. 19, iss. 1

15--25

EN

A series of 2-Amino-4-isopropyl-6-methoxy-N-phenylpyrimidine-5-carboxamide compounds have been synthesized from various substituted dithioacetal and guanidine. The purities of these compounds were checked by their physical constants, UV, IR, NMR and MASS spectral data. The IR and 1HNMR spectral data of these compounds have been correlated with Hammett sigma constants, F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effects of substituents on the spectral group frequencies have been discussed.

2

On n-pi Elektron Distribution in Simple Keto-Enol tautomeric Systems: H3C-C(R)=O==H2C=C(R)-OH and RH@C-CH=O==RHC=CH-OH

100%

Raczyńska E.

Polish Journal of Chemistry

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2005

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tom Vol. 79 / nr 4

749-758

EN

Variations of the n- electron distribution during the tautomeric interconversion and substituent effects were analysed for simple keto-enol tautomeric systems of general formulae H3C-C(R)=O H2C=C(R)-OH and RH2C-CH=O RHC=CH-OH using the geometry-based HOMA index.

3

NMR Spectral correlations in some Tröger’s bases

100%

Thirunarayanan G. , Suresh M.

International Letters of Chemistry, Physics and Astronomy

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2014

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tom Vol. 4

1--11

EN

Some Tröger’s bases have been synthesised from substituted anilines and paraformaldehyde in presence of Lewis acid catalyst such as anhydrous AlCl3, through electrophilic substitution reaction. The purities of these Tröger’s bases have been checked by their physical constants and spectroscopic data published earlier in the literature. The NMR chemical shift (δ, ppm) of methylene protons and carbon were assigned. The assigned methylene protons and carbon chemical shifts (δ, ppm) of synthesised Tröger’s bases have been correlated with Hammett substituent constants, F and R parameters using single and multi-regression analyses. From the results of statistical analyses, the effects of substituent on methylene protons and carbon were discussed.

4

Statistical Analysis of Consequences of peri-Interactions in 1-Si, 8-N- (and 1-X, 8-Y-) Substituted Naphthalenesin 1-Si, 8-N- (and 1-X, 8-Y-) Substituted Naphthalenes

88%

Dominiak P. , Schiemenz G. , Woźniak K.

Polish Journal of Chemistry

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2007

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tom Vol. 81, nr 5-6

663-681

EN

A statistical analysis of geometrical parameters for 1-Si, 8-N-substituted naphthalenes retrieved from the CSD revealed three factors describing structural consequences of peri interactions in such derivatives. The most important of them is an in-plane deformation whichmay be estimated by a linear combination of several geometrical parameters of the naphthalene fragment. It is best approximated by values of splay angles. The second consequence is an out-of-plane deformation formally defined by all torsion angles. It is well approximated by the Si–C(1)…C(8)–N torsion angle. The third factor can be associated with substituent effects and it manifests itself mainly by changes of Car-N/Si bond lengths and their ipso angles. Similar analysis performed for a more general data set consisting of 1-X, 8-Y-disubstituted naphthalenes fully supports the above interpretation. The peri X…Y distance (PD) can be expressed as linear combinations of the factors obtained, which leads to a multiple regression line with the value of the free term very close to PD and coefficients being relative weights of particular factors. It appears that in plane deformation contributes to the d(X...Y) distance farmore significantly than the other factors.

5

Structure parameter correlation of some quinoxaline derivatives through IR and 13C NMR spectra

88%

Thirunarayanan G. , Muthuvel I. , Sathiyendiran V.

International Letters of Chemistry, Physics and Astronomy

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2014

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tom Vol. 19, iss. 2

198--207

EN

A series of 6-substituted quanoxaline derivatives have been synthesized and examined their purities by literature method. The infrared and 13>/Sup>C NMR spectral data of these quinoxalines were correlated with Hammett substituent constants, F and R parameters using single and multi-regression analysis. From the results of statistical analysis, the effect of substituents on the spectral frequencies has been studied.

6

Spectral correlation analysis and antimicrobial activities of some 2,4-dimethoxy phenyl chalcones

75%

Joseph S. J. , Arulkumaran R. , Kamalakkannan D. , Sakthinathan S. P. , Sundararajan R. , Suresh R. , Vijayakumar S. , Ranganathan K. , Kalyanasundaram N. , Vanangamudi G. , Thirunarayanan G.

International Letters of Chemistry, Physics and Astronomy

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2014

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tom Vol. 4

48--65

EN

A series of 2,4-dimethoxy phenyl chalcones have been synthesized by Crossed-Aldol condensation of 2,4-dimethoxy phenyl and various substituted benzaldehydes. The purities of these chalcones have been checked by their physical constants, UV, IR, NMR and MASS spectral data. The spectral data of these chalcones have been correlated with Hammett sigma constants, F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effects of substituents on the spectral group frequencies have been discussed. The anti-microbial activities of these chalcones have been evaluated using Bauer-Kirby method.

7

Modelling drug-receptor interactions in an average binding site for NK2

75%

Alagona G. , Ghio C. , Monti S.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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1998

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tom Vol. 2, No 4

563-581

EN

A tentative procedure applied to the search for a new antagonist of neurokinin A (NKA) is presented. In parallel a tentative 3-D model of the NK2 receptor was created, using bacteriorhodopsin (BRD) as a template. The residue substitutions were performed in BRD to obtain the sequence for NK2R_H and the seven a-helical segments were optimized forcing the a-helical backbone to match the corresponding aligned parts of BRD, while the arrangements of the side chains were model built based on available site-directed mutagenesis studies. Constrained MM and molecular dynamics simulations were carried out H-bonding a low energy conformer of the known drugs to residues in the receptor site, allowing both the receptor site and drugs to relax. The Connolly surface for each ligand allowed to determine an "average" binding site in which all the low energy conformers of known and prospective drugs were docked and classified according to a statistical index. The whole procedure was repeated exploiting the lately published structure of an actual G protein coupled receptor as a better template, thus producing a cavity in the binding site to directly dock the drugs. Corollary validations of the force fields used are also mentioned. In addition intra- and intermolecular interactions suitable to produce more active drugs were evaluated.

8

Spectral correlations and antimicrobial activities of some 1-pyrenyl chalcones

75%

Arulkumaran R. , Vijayakumar S. , Sundararajan R. , Sakthinathan S. P. , Kamalakkannan D. , Suresh R. , Ranganathan K. , Rajakumar P. R.

International Letters of Chemistry, Physics and Astronomy

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2013

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tom Vol. 5

21-38

EN

A series of 1-pyrenyl chalcones have been synthesized by Crossed-Aldol condensation of 1-acetylpyrene and substituted benzaldehydes. The purities of these chalcones have been checked by their physical constants, UV, IR, NMR and MASS spectral data. The spectral data of these chalcones have been correlated with Hammett sigma constants, F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the spectral group frequencies have been discussed. The anti-microbial activities of these chalcones have been evaluated using Bauer-Kirby method.

9

Spectral correlation analysis of Hammett substituent constants and biological activities of some (E)-1-(4-phenoxyphenyl)-3-phenylprop-2-en-1-ones

75%

Kalyanasundaram N. , Sakthinathan S. P. , Suresh R. , Kamalakkannan D. , Joseph S. J. , Vanangamudi G. , Thirunarayanan G.

International Letters of Chemistry, Physics and Astronomy

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2014

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tom Vol. 9

23--47

EN

A series of aryl chalcones have been synthesized from 4-phenoxyacetophonone with various substituted benzaldehydes. The purity of all chalcones has been checked using their physical constants and spectral data. These spectral data have been correlated with Hammett substituent constants and F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the above spectral data has been studied. The single parameter correlation with few Hammett constants and F and R parameters gave satisfactory correlation coefficients whereas all multiple correlations gave satisfactory correlation coefficients with Resonance, Field and Swain-Lupton’s parameters. The antimicrobial activities of all chalcones have been studied using Bauer-Kirby method.

10

Optical Properties of Some 4-Aryl-1H-pyrazolo[3,4-b]quinolines

75%

Kkachatryan K. , Boszczyk W. , Tomasik P.

Polish Journal of Chemistry

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2005

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tom Vol. 79 / nr 10

1645-1657

EN

Series of 6-substituted 4-(4_-tolyl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]quinolines (1) and 4-(4_-chlorophenyl)- 3-methyl-1-phenyl-1H-pyrazolo[3,4-b]quinolines (2) were synthesized and their solution absorption and emission spectra in 10 solvents were recorded. Positions and intensity of the emission and longest wavelength absorption band as well as the quantum yield of emission and its lifetime were analysed in terms of the corresponding identity criteria involving a given parameter ifrom series (1) against the same parameters from the series (2). Mostly only tendencies to the linearity were observed in terms of the correlation coefficient.

11

Assessment of substituent effects and antimicrobial activities of some 2ʹ,5ʹ-dimethyl phenyl chalcones

75%

Joseph S. J. , Kamalakkannan D. , Arulkumaran R. , Sakthinathan S. P. , Suresh R. , Sundararajan R. , Vijayakumar S. , Ranganathan K. , Vanangamudi G. , Thirunarayanan G.

International Letters of Chemistry, Physics and Astronomy

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2014

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tom Vol. 5

99-123

EN

Some 2ʹ,5ʹ-dimethyl phenyl chalcones have been synthesized by Crossed-Aldol condensation between 2,5-dimethyl acetophenone and various substituted benzaldehydes using catalytic amount of sodium hydroxide and ethanol. The yields of the chalcones are more than 93 %. The purities of these chalcones have been checked by their physical constants, UV, IR, NMR and MASS spectral data. The spectral data of these chalcones have been correlated with Hammett sigma constants, F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effects of substituents on the spectral group frequencies have been discussed. The anti-microbial activities of these chalcones have been evaluated using Bauer-Kirby method.

12

Thionylchloride catalyzed aldol condensation: Synthesis, spectral correlation and antibacterial activities of some 3,5-dichloro-2-hydroxyphenyl chalcones

51%

Arulkumaran R. , Vijayakumar S. , Sundararajan R. , Sakthinathan S. P. , Kamalakkannan D. , Suresh R. , Ranganathan K. , Vanangamudi G. , Thirunarayanan G.

International Letters of Chemistry, Physics and Astronomy

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2012

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tom Vol. 4

17-38

EN

A series of substituted styryl 3,5-dichloro-2-hydroxyphenyl ketones [1-(3, 5-dichloro-2-hydroxy)- 3-phenylprop-2-en-1-one] were synthesized using thionyl chloride assisted Crossed Aldol reaction. The yields of chalcones were more than 80%. The synthesized chalcones were characterized by analytical and spectroscopic data. From the spectroscopic data the group frequencies were correlated with Hammett substituent constants, F and R parameters. From the results of statistical analysis the effect of substituents were discussed. The antibacterial activities of these chalcones have been evaluated using Bauer-Kirby method.