Rytis Kubilius - Academia.edu (original) (raw)
Papers by Rytis Kubilius
Journal of the Chemical Society, 1999
![Research paper thumbnail of ChemInform Abstract: Intramolecular Ring Closure via Ether Bond in Reaction of α,α′-Halogeno Bicyclo[3.3.1]nonanediones under Basic Conditions](https://attachments.academia-assets.com/110904714/thumbnails/1.jpg)
](ChemInform, Jun 13, 2010
Intramolecular Ring Closure via Ether Bond in Reaction of α,α'-Halogeno Bicyclo[3.3.1]nonanedione... more Intramolecular Ring Closure via Ether Bond in Reaction of α,α'-Halogeno Bicyclo[3.3.1]nonanediones under Basic Conditions.-In the presence of sodium alkoxides and KCN the dihalogeno diones (II) and (VII) undergo unprecedented intramolecular ring closure to oxaprotoadamantanes. The bromo ketone (IX), however, yields the substitution product (X).
![Research paper thumbnail of Enantiomer separation and absolute configuration of densely functionalized 2-oxatricyclo[4.3.1.03,8]decanes by CD spectroscopy and chemical correlation](https://attachments.academia-assets.com/110904718/thumbnails/1.jpg)
](Tetrahedron-asymmetry, Aug 1, 2000
Enantiomer separation by HPLC on a swollen microcrystalline triacetylcellulose column of highly s... more Enantiomer separation by HPLC on a swollen microcrystalline triacetylcellulose column of highly substituted 2-oxatricyclo[4.3.1.0 3,8 ]decane (2-oxaprotoadamantane) structures aorded enantiomers of this molecule. Application of the octant rule to the carbonyl chromophore to establish the absolute con®guration of the enantiomers did not lead to an unequivocal conclusion. The enantioselective synthesis of 4-bromo-3methoxy-oxaprotoadamantanone was performed from homochiral (+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6dione thus permitting the assignment of the (1R,3S,4S,6R,8R)-con®guration to the title structures.
ChemInform, Aug 3, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Russian Chemical Bulletin, Feb 1, 1997
Transformations of α-chloro- and α-bromobicyclo[3.3.1]nonanones under conditions of the Favorskii... more Transformations of α-chloro- and α-bromobicyclo[3.3.1]nonanones under conditions of the Favorskii reaction were studied. The interaction of dihalodiketones with MeONa gives 2-oxatricyclo[4.3.1.03.8]decane (oxaprotoadamantane) derivatives as a result of intramolecular cyclization, whereas 3-bromobicyclononanone undergoes only nucleophilic substitution of bromine.
European Journal of Inorganic Chemistry, 2015
The pyrotechnic flames of Ba(NO3)2, NH4ClO4, and shellac compositions have been analyzed spectrop... more The pyrotechnic flames of Ba(NO3)2, NH4ClO4, and shellac compositions have been analyzed spectrophotometrically. The oxidizer ratio and oxygen balance were varied in a series of compositions to investigate how this ratio influences the flame emission spectra and burning properties of pyrotechnic compositions. The burning rate, emission spectra, and chromaticity data and their analysis are presented.
ChemInform, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Chemistry – A European Journal, 2015
Copper(I) bromide was evaluated as an alternative emitter for blue flame pyrotechnic compositions... more Copper(I) bromide was evaluated as an alternative emitter for blue flame pyrotechnic compositions. CuBr and CuCl emission spectra were recorded from a butane torch flame and compared. Cu(BrO3)2 was synthesized and used in pyrotechnic compositions as an oxidizer and the source for the generation of CuBr species. Pyrotechnic compositions, which contained copper and potassium bromates as oxidizers, were optimized for the generation of blue flames. The experimental data, including emission spectra of the flames, chromaticity coordinates, burning rates, luminous intensities, and sensitivity tests, were analyzed and compared.
Journal of Computational Chemistry, 2015
Aqueous pK a of selected primary benzenesulfonamides are predicted in a systematic manner using d... more Aqueous pK a of selected primary benzenesulfonamides are predicted in a systematic manner using density functional theory methods and the SMD solvent model together with direct and proton exchange thermodynamic cycles. Some test calculations were also performed using high-level composite CBS-QB3 approach. The direct scheme generally does not yield a satisfactory agreement between calculated and measured acidities due to a severe overestimation of the Gibbs free energy changes of the gas-phase deprotonation reaction by the used exchange-correlation functionals. The relative pK a values calculated using proton exchange method compare to experimental data very well in both qualitative and quantitative terms, with a mean absolute error of about 0.4 pK a units. To achieve this accuracy, we find it mandatory to perform geometry optimization of the neutral and anionic species in the gas and solution phases separately, because different conformations are stabilized in these two cases. We have attempted to evaluate the effect of the conformer-averaged free energies in the pK a predictions, and the general conclusion is that this procedure is highly too costly as compared with the very small improvement we have gained.
Zeitschrift für anorganische und allgemeine Chemie, 2014
Red pyrotechnic flames are mostly produced using strontium compounds. Flame color quality is depe... more Red pyrotechnic flames are mostly produced using strontium compounds. Flame color quality is dependent on the chemical composition of the mixture. The emission spectrum produced by strontium monohydroxide (SrOH) and strontium monochloride (SrCl) species in red colored flames was measured, analyzed, and compared. Chlorine was introduced into standard composition of anhydrous strontium nitrate and shellac using three different classical oxidizers – chlorine donors: potassium chlorate, potassium perchlorate, and ammonium perchlorate. Color points and excitation purity in CIE 1931 chromaticity diagram were calculated.
![Research paper thumbnail of Enantiomer separation and absolute configuration of densely functionalized 2-oxatricyclo[4.3.1.03,8]decanes by CD spectroscopy and chemical correlation](https://attachments.academia-assets.com/110904717/thumbnails/1.jpg)
](Tetrahedron: Asymmetry, 2000
Enantiomer separation by HPLC on a swollen microcrystalline triacetylcellulose column of highly s... more Enantiomer separation by HPLC on a swollen microcrystalline triacetylcellulose column of highly substituted 2-oxatricyclo[4.3.1.0 3,8 ]decane (2-oxaprotoadamantane) structures aorded enantiomers of this molecule. Application of the octant rule to the carbonyl chromophore to establish the absolute con®guration of the enantiomers did not lead to an unequivocal conclusion. The enantioselective synthesis of 4-bromo-3methoxy-oxaprotoadamantanone was performed from homochiral (+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6dione thus permitting the assignment of the (1R,3S,4S,6R,8R)-con®guration to the title structures.
Russian Chemical Bulletin, 1997
Transformations of α-chloro- and α-bromobicyclo[3.3.1]nonanones under conditions of the Favorskii... more Transformations of α-chloro- and α-bromobicyclo[3.3.1]nonanones under conditions of the Favorskii reaction were studied. The interaction of dihalodiketones with MeONa gives 2-oxatricyclo[4.3.1.03.8]decane (oxaprotoadamantane) derivatives as a result of intramolecular cyclization, whereas 3-bromobicyclononanone undergoes only nucleophilic substitution of bromine.
![Research paper thumbnail of Ring contraction/transannular cyclization of chiral bicyclo[3.3.1]nonanediones mediated by thallium(III) nitrate](https://attachments.academia-assets.com/110904703/thumbnails/1.jpg)
](Tetrahedron Letters, 2011
Journal of the Chemical Society, 1999
ChemInform, Jun 13, 2010
Intramolecular Ring Closure via Ether Bond in Reaction of α,α'-Halogeno Bicyclo[3.3.1]nonanedione... more Intramolecular Ring Closure via Ether Bond in Reaction of α,α'-Halogeno Bicyclo[3.3.1]nonanediones under Basic Conditions.-In the presence of sodium alkoxides and KCN the dihalogeno diones (II) and (VII) undergo unprecedented intramolecular ring closure to oxaprotoadamantanes. The bromo ketone (IX), however, yields the substitution product (X).
Tetrahedron-asymmetry, Aug 1, 2000
Enantiomer separation by HPLC on a swollen microcrystalline triacetylcellulose column of highly s... more Enantiomer separation by HPLC on a swollen microcrystalline triacetylcellulose column of highly substituted 2-oxatricyclo[4.3.1.0 3,8 ]decane (2-oxaprotoadamantane) structures aorded enantiomers of this molecule. Application of the octant rule to the carbonyl chromophore to establish the absolute con®guration of the enantiomers did not lead to an unequivocal conclusion. The enantioselective synthesis of 4-bromo-3methoxy-oxaprotoadamantanone was performed from homochiral (+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6dione thus permitting the assignment of the (1R,3S,4S,6R,8R)-con®guration to the title structures.
ChemInform, Aug 3, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Russian Chemical Bulletin, Feb 1, 1997
Transformations of α-chloro- and α-bromobicyclo[3.3.1]nonanones under conditions of the Favorskii... more Transformations of α-chloro- and α-bromobicyclo[3.3.1]nonanones under conditions of the Favorskii reaction were studied. The interaction of dihalodiketones with MeONa gives 2-oxatricyclo[4.3.1.03.8]decane (oxaprotoadamantane) derivatives as a result of intramolecular cyclization, whereas 3-bromobicyclononanone undergoes only nucleophilic substitution of bromine.
European Journal of Inorganic Chemistry, 2015
The pyrotechnic flames of Ba(NO3)2, NH4ClO4, and shellac compositions have been analyzed spectrop... more The pyrotechnic flames of Ba(NO3)2, NH4ClO4, and shellac compositions have been analyzed spectrophotometrically. The oxidizer ratio and oxygen balance were varied in a series of compositions to investigate how this ratio influences the flame emission spectra and burning properties of pyrotechnic compositions. The burning rate, emission spectra, and chromaticity data and their analysis are presented.
ChemInform, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Chemistry – A European Journal, 2015
Copper(I) bromide was evaluated as an alternative emitter for blue flame pyrotechnic compositions... more Copper(I) bromide was evaluated as an alternative emitter for blue flame pyrotechnic compositions. CuBr and CuCl emission spectra were recorded from a butane torch flame and compared. Cu(BrO3)2 was synthesized and used in pyrotechnic compositions as an oxidizer and the source for the generation of CuBr species. Pyrotechnic compositions, which contained copper and potassium bromates as oxidizers, were optimized for the generation of blue flames. The experimental data, including emission spectra of the flames, chromaticity coordinates, burning rates, luminous intensities, and sensitivity tests, were analyzed and compared.
Journal of Computational Chemistry, 2015
Aqueous pK a of selected primary benzenesulfonamides are predicted in a systematic manner using d... more Aqueous pK a of selected primary benzenesulfonamides are predicted in a systematic manner using density functional theory methods and the SMD solvent model together with direct and proton exchange thermodynamic cycles. Some test calculations were also performed using high-level composite CBS-QB3 approach. The direct scheme generally does not yield a satisfactory agreement between calculated and measured acidities due to a severe overestimation of the Gibbs free energy changes of the gas-phase deprotonation reaction by the used exchange-correlation functionals. The relative pK a values calculated using proton exchange method compare to experimental data very well in both qualitative and quantitative terms, with a mean absolute error of about 0.4 pK a units. To achieve this accuracy, we find it mandatory to perform geometry optimization of the neutral and anionic species in the gas and solution phases separately, because different conformations are stabilized in these two cases. We have attempted to evaluate the effect of the conformer-averaged free energies in the pK a predictions, and the general conclusion is that this procedure is highly too costly as compared with the very small improvement we have gained.
Zeitschrift für anorganische und allgemeine Chemie, 2014
Red pyrotechnic flames are mostly produced using strontium compounds. Flame color quality is depe... more Red pyrotechnic flames are mostly produced using strontium compounds. Flame color quality is dependent on the chemical composition of the mixture. The emission spectrum produced by strontium monohydroxide (SrOH) and strontium monochloride (SrCl) species in red colored flames was measured, analyzed, and compared. Chlorine was introduced into standard composition of anhydrous strontium nitrate and shellac using three different classical oxidizers – chlorine donors: potassium chlorate, potassium perchlorate, and ammonium perchlorate. Color points and excitation purity in CIE 1931 chromaticity diagram were calculated.
Tetrahedron: Asymmetry, 2000
Enantiomer separation by HPLC on a swollen microcrystalline triacetylcellulose column of highly s... more Enantiomer separation by HPLC on a swollen microcrystalline triacetylcellulose column of highly substituted 2-oxatricyclo[4.3.1.0 3,8 ]decane (2-oxaprotoadamantane) structures aorded enantiomers of this molecule. Application of the octant rule to the carbonyl chromophore to establish the absolute con®guration of the enantiomers did not lead to an unequivocal conclusion. The enantioselective synthesis of 4-bromo-3methoxy-oxaprotoadamantanone was performed from homochiral (+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6dione thus permitting the assignment of the (1R,3S,4S,6R,8R)-con®guration to the title structures.
Russian Chemical Bulletin, 1997
Transformations of α-chloro- and α-bromobicyclo[3.3.1]nonanones under conditions of the Favorskii... more Transformations of α-chloro- and α-bromobicyclo[3.3.1]nonanones under conditions of the Favorskii reaction were studied. The interaction of dihalodiketones with MeONa gives 2-oxatricyclo[4.3.1.03.8]decane (oxaprotoadamantane) derivatives as a result of intramolecular cyclization, whereas 3-bromobicyclononanone undergoes only nucleophilic substitution of bromine.
Tetrahedron Letters, 2011