ABSTRACT Derivatives of bis-2-oxazolines containing inner unsaturation, 1,3- and 1,4-bis[2-(4,4-d... more ABSTRACT Derivatives of bis-2-oxazolines containing inner unsaturation, 1,3- and 1,4-bis[2-(4,4-dimethyl-2-oxazolin-2-yl)ethenyl]benzenes, were isolated in 48.5% and 59.9% yields by the condensation reaction of isophthaldialdehyde and terephthaldialdehyde with 2-alkyl-2-oxazolines catalyzed by iodine, p-toluenesulfonic acid, ZnCl2, and NaHSO4 in a solution with azeotropical removal of the condensation water. Acidic hydrolysis of these derivatives provided p- and m-phenylenediacrylic acids in 92% yields in both cases.
Modification of polyolefins by a low-temperature discharge plasma is very frequently used in auto... more Modification of polyolefins by a low-temperature discharge plasma is very frequently used in automotive industry, for upholstery production, bumpers covering by varnishes as well as in the production of plastics elements for car interiors. The worldwide production of low-density polyethylene (LDPE) reaches the highest value among the polymers produced for many industrial applications including the automotive industry (bumpers or steering wheels manufacture). However, it is polymer with chemically inert and hydrophobic character, what is limiting to the further processing. This lack of LDPE properties can be removed by the surface modification of LDPE by the low-temperature plasma. Moreover, the plasma discharge can be used for surface treatment by biocompatible materials such as poly(oxazoline) to improve the adhesion of the laminating materials.
The non-covalent interactions between 2-oxazoline containing phenols and an aliphatic polyamidine... more The non-covalent interactions between 2-oxazoline containing phenols and an aliphatic polyamidines as well as an inorganic base were studied. The reaction of a weak acid with a strong base results in the formation of the deprotonated species and subsequently in the formation of a new electronic structure. A bathochromic shift of the wavelength of the absorption maxima of the chromophores bounded to polyamidine was observed. Depending on the structure of the chromophore, the shift of the absorption maxima is 40-100 nm. The changes in photochemical behavior can be explained by the higher portion of quinoid structures in the conjugated π-system. The degree of deprotonation is dependent on the molar ratio of the chromophore and the polymeric base. Analogous results were obtained with an inorganic base.
Cell encapsulation has been intensively studied as an effective way of immune-protection of cells... more Cell encapsulation has been intensively studied as an effective way of immune-protection of cells intended for cellular therapy. Various biocompatible materials have been already developed for this specific purpose. Regardless of the chemical composition, all materials intended for long-term in vivo biomedical applications have to meet the requirements considering chemical and mechanical stability (Calafiore et al., 2014). Comprehensive analysis of physico-chemical properties should therefore be an integral part of material characterization. Since physico-chemical properties may vary in time, this might be considered and studied in detail. Several analytical methods for material characterization have been recently reviewed by Rokstad et al. (2014). In this study, we focused on the chemical and mechanical stability of PMCG microcapsules, serving as possible immune-protective devices for cellular therapy of patients suffering from Diabetes Type 1 (Lacik, 2013).
Crystal structures are reported for three isomeric compounds, namely 2-(2-hydroxyphenyl)-2-oxazol... more Crystal structures are reported for three isomeric compounds, namely 2-(2-hydroxyphenyl)-2-oxazoline, (I), 2-(3-hydroxyphenyl)-2-oxazoline, (II), and 2-(4-hydroxyphenyl)-2-oxazoline, (III), all C9H9NO2 [systematic names: 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (I), 3-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (II), and 4-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (III)]. In these compounds, the deviation from coplanarity of the oxazoline and benzene rings is dependent on the position of the hydroxy group on the benzene ring. The coplanar arrangement in (I) is stabilized by a strong intramolecular O-H...N hydrogen bond. Surprisingly, the 2-oxazoline ring in molecule B of (II) adopts a 3T4 (C2TC3) conformation, while the 2-oxazoline ring in molecule A, as well as that in (I) and (III), is nearly planar, as expected. Tetramers of molecules of (II) are formed and they are bound together via weak C-H...N hydrogen bonds. In (III), strong intermolecular O-H...N hydrogen bonds and weak intramolecular C-...
In the crystal structure of the title compound, C(11)H(13)NO(2), there are strong intermolecular ... more In the crystal structure of the title compound, C(11)H(13)NO(2), there are strong intermolecular O-H...N hydrogen bonds which, together with weak intramolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules, held together by weak intermolecular C-H...O hydrogen bonds. A theoretical investigation of the hydrogen bonding, based on density functional theory (DFT) employing periodic boundary conditions, is in agreement with the experimental data. The cluster approach shows that the influence of the crystal field and of hydrogen-bond formation are responsible for the deformation of the 2-oxazoline ring, which is not planar and adopts a (4)T(3) ((C3)T(C2)) conformation.
In the crystal structure of the title compound, C(9)H(9)NO(3), there are strong intramolecular O-... more In the crystal structure of the title compound, C(9)H(9)NO(3), there are strong intramolecular O-H...N and intermolecular O-H...O hydrogen bonds which, together with weak intermolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules. The calculated intermolecular hydrogen-bond energies are -11.3 and -2.7 kJ mol(-1), respectively, showing the dominant role of the O-H...O hydrogen bonding. A natural bond orbital analysis revealed the electron contribution of the lone pairs of the oxazoline N and O atoms, and of the two hydroxy O atoms, to the order of the relevant bonds.
ABSTRACT Two azobenzene containing 2-oxazolines were used for labelling of polyesters with carbox... more ABSTRACT Two azobenzene containing 2-oxazolines were used for labelling of polyesters with carboxylic end groups by the end-capping method. The reaction proceeded under the conditions of reactive processing, and in a solution. High conversions in melt were achieved in several minutes. The coupling of the modifiers was proved by NMR spectroscopy.
An AB 2 monomer containing one oxazoline and two phenolic units was synthesized. The polymerizati... more An AB 2 monomer containing one oxazoline and two phenolic units was synthesized. The polymerization of the monomer 2-(3,5-dihydroxyphenyl)-1,3-oxazoline in N-methylcaprolactam resulted in a well-defined and fully soluble, high molar mass, hyperbranched polymer with etheramide ...
Multiple chemical attachments of carbohydrate antigens to linear polymer represent promising tech... more Multiple chemical attachments of carbohydrate antigens to linear polymer represent promising technique for creating biologically effective conjugates. A novel conjugate consisting of detoxified lipopolysaccharide of Vibrio cholerae O135, linear polymer (polyoxazoline copolymer, serving as a matrix) and BSA (as immunogenic protein), has been prepared. The reaction conditions were optimized for obtaining high degree of conjugation. Analytical methods were evaluated to characterize conjugates obtained. Proposed chemistry is suitable for preparation of multivalent glycoconjugates in general.
Collection of Czechoslovak Chemical Communications, 2007
ABSTRACT Conjugated acyclic arylamine derivatives, N -(4-methylphenyl)- N -(2-methyl-1-phenylprop... more ABSTRACT Conjugated acyclic arylamine derivatives, N -(4-methylphenyl)- N -(2-methyl-1-phenylpropyl)amine and N -(4-methoxyphenyl)- N -(2-methyl-1-phenylpropyl)amine, have been synthesized and characterized. Their photophysical properties have been investigated in polar methanol and non-polar cyclohexane solutions, and in PS and PMMA polymer matrices. The influence of the environment polarity as well as of the substituent in para -position of the aryl on the absorption, emission spectra and the fluorescence quantum yield has been studied. In the absorption and emission spectra, the observed absorption and emission band maxima were red shifted and the observed quantum yield was higher in the polar solution in comparison with the non-polar solution or polymer matrices. The distance of short- and long-wavelength absorption maxima in the methoxy derivative was larger and the emission band was red shifted in comparison with the methyl derivative. Chemical and photochemical oxidation of the prepared amines gives unstable nitroxides. High intramolecular quenching was observed in polymer matrix after photochemical oxidation of the amines.
ABSTRACT A range of cinnamic units containing 4,5-dihydrooxazoles was prepared using two differen... more ABSTRACT A range of cinnamic units containing 4,5-dihydrooxazoles was prepared using two different synthetic routes. The first method was based on the transformation of substituted cinnamic or benzoic acids to 2-styryl-4,5-dihydrooxazoles. Several derivatives containing phenolic groups were prepared in this manner. The second approach consisted of a reaction between the 4,5-dihydrooxazole moiety and double bond-containing compounds. These compounds contain two or more reactive centres capable of providing polymerisations and also organic reactions.
ABSTRACT Derivatives of bis-2-oxazolines containing inner unsaturation, 1,3- and 1,4-bis[2-(4,4-d... more ABSTRACT Derivatives of bis-2-oxazolines containing inner unsaturation, 1,3- and 1,4-bis[2-(4,4-dimethyl-2-oxazolin-2-yl)ethenyl]benzenes, were isolated in 48.5% and 59.9% yields by the condensation reaction of isophthaldialdehyde and terephthaldialdehyde with 2-alkyl-2-oxazolines catalyzed by iodine, p-toluenesulfonic acid, ZnCl2, and NaHSO4 in a solution with azeotropical removal of the condensation water. Acidic hydrolysis of these derivatives provided p- and m-phenylenediacrylic acids in 92% yields in both cases.
Modification of polyolefins by a low-temperature discharge plasma is very frequently used in auto... more Modification of polyolefins by a low-temperature discharge plasma is very frequently used in automotive industry, for upholstery production, bumpers covering by varnishes as well as in the production of plastics elements for car interiors. The worldwide production of low-density polyethylene (LDPE) reaches the highest value among the polymers produced for many industrial applications including the automotive industry (bumpers or steering wheels manufacture). However, it is polymer with chemically inert and hydrophobic character, what is limiting to the further processing. This lack of LDPE properties can be removed by the surface modification of LDPE by the low-temperature plasma. Moreover, the plasma discharge can be used for surface treatment by biocompatible materials such as poly(oxazoline) to improve the adhesion of the laminating materials.
The non-covalent interactions between 2-oxazoline containing phenols and an aliphatic polyamidine... more The non-covalent interactions between 2-oxazoline containing phenols and an aliphatic polyamidines as well as an inorganic base were studied. The reaction of a weak acid with a strong base results in the formation of the deprotonated species and subsequently in the formation of a new electronic structure. A bathochromic shift of the wavelength of the absorption maxima of the chromophores bounded to polyamidine was observed. Depending on the structure of the chromophore, the shift of the absorption maxima is 40-100 nm. The changes in photochemical behavior can be explained by the higher portion of quinoid structures in the conjugated π-system. The degree of deprotonation is dependent on the molar ratio of the chromophore and the polymeric base. Analogous results were obtained with an inorganic base.
Cell encapsulation has been intensively studied as an effective way of immune-protection of cells... more Cell encapsulation has been intensively studied as an effective way of immune-protection of cells intended for cellular therapy. Various biocompatible materials have been already developed for this specific purpose. Regardless of the chemical composition, all materials intended for long-term in vivo biomedical applications have to meet the requirements considering chemical and mechanical stability (Calafiore et al., 2014). Comprehensive analysis of physico-chemical properties should therefore be an integral part of material characterization. Since physico-chemical properties may vary in time, this might be considered and studied in detail. Several analytical methods for material characterization have been recently reviewed by Rokstad et al. (2014). In this study, we focused on the chemical and mechanical stability of PMCG microcapsules, serving as possible immune-protective devices for cellular therapy of patients suffering from Diabetes Type 1 (Lacik, 2013).
Crystal structures are reported for three isomeric compounds, namely 2-(2-hydroxyphenyl)-2-oxazol... more Crystal structures are reported for three isomeric compounds, namely 2-(2-hydroxyphenyl)-2-oxazoline, (I), 2-(3-hydroxyphenyl)-2-oxazoline, (II), and 2-(4-hydroxyphenyl)-2-oxazoline, (III), all C9H9NO2 [systematic names: 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (I), 3-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (II), and 4-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (III)]. In these compounds, the deviation from coplanarity of the oxazoline and benzene rings is dependent on the position of the hydroxy group on the benzene ring. The coplanar arrangement in (I) is stabilized by a strong intramolecular O-H...N hydrogen bond. Surprisingly, the 2-oxazoline ring in molecule B of (II) adopts a 3T4 (C2TC3) conformation, while the 2-oxazoline ring in molecule A, as well as that in (I) and (III), is nearly planar, as expected. Tetramers of molecules of (II) are formed and they are bound together via weak C-H...N hydrogen bonds. In (III), strong intermolecular O-H...N hydrogen bonds and weak intramolecular C-...
In the crystal structure of the title compound, C(11)H(13)NO(2), there are strong intermolecular ... more In the crystal structure of the title compound, C(11)H(13)NO(2), there are strong intermolecular O-H...N hydrogen bonds which, together with weak intramolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules, held together by weak intermolecular C-H...O hydrogen bonds. A theoretical investigation of the hydrogen bonding, based on density functional theory (DFT) employing periodic boundary conditions, is in agreement with the experimental data. The cluster approach shows that the influence of the crystal field and of hydrogen-bond formation are responsible for the deformation of the 2-oxazoline ring, which is not planar and adopts a (4)T(3) ((C3)T(C2)) conformation.
In the crystal structure of the title compound, C(9)H(9)NO(3), there are strong intramolecular O-... more In the crystal structure of the title compound, C(9)H(9)NO(3), there are strong intramolecular O-H...N and intermolecular O-H...O hydrogen bonds which, together with weak intermolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules. The calculated intermolecular hydrogen-bond energies are -11.3 and -2.7 kJ mol(-1), respectively, showing the dominant role of the O-H...O hydrogen bonding. A natural bond orbital analysis revealed the electron contribution of the lone pairs of the oxazoline N and O atoms, and of the two hydroxy O atoms, to the order of the relevant bonds.
ABSTRACT Two azobenzene containing 2-oxazolines were used for labelling of polyesters with carbox... more ABSTRACT Two azobenzene containing 2-oxazolines were used for labelling of polyesters with carboxylic end groups by the end-capping method. The reaction proceeded under the conditions of reactive processing, and in a solution. High conversions in melt were achieved in several minutes. The coupling of the modifiers was proved by NMR spectroscopy.
An AB 2 monomer containing one oxazoline and two phenolic units was synthesized. The polymerizati... more An AB 2 monomer containing one oxazoline and two phenolic units was synthesized. The polymerization of the monomer 2-(3,5-dihydroxyphenyl)-1,3-oxazoline in N-methylcaprolactam resulted in a well-defined and fully soluble, high molar mass, hyperbranched polymer with etheramide ...
Multiple chemical attachments of carbohydrate antigens to linear polymer represent promising tech... more Multiple chemical attachments of carbohydrate antigens to linear polymer represent promising technique for creating biologically effective conjugates. A novel conjugate consisting of detoxified lipopolysaccharide of Vibrio cholerae O135, linear polymer (polyoxazoline copolymer, serving as a matrix) and BSA (as immunogenic protein), has been prepared. The reaction conditions were optimized for obtaining high degree of conjugation. Analytical methods were evaluated to characterize conjugates obtained. Proposed chemistry is suitable for preparation of multivalent glycoconjugates in general.
Collection of Czechoslovak Chemical Communications, 2007
ABSTRACT Conjugated acyclic arylamine derivatives, N -(4-methylphenyl)- N -(2-methyl-1-phenylprop... more ABSTRACT Conjugated acyclic arylamine derivatives, N -(4-methylphenyl)- N -(2-methyl-1-phenylpropyl)amine and N -(4-methoxyphenyl)- N -(2-methyl-1-phenylpropyl)amine, have been synthesized and characterized. Their photophysical properties have been investigated in polar methanol and non-polar cyclohexane solutions, and in PS and PMMA polymer matrices. The influence of the environment polarity as well as of the substituent in para -position of the aryl on the absorption, emission spectra and the fluorescence quantum yield has been studied. In the absorption and emission spectra, the observed absorption and emission band maxima were red shifted and the observed quantum yield was higher in the polar solution in comparison with the non-polar solution or polymer matrices. The distance of short- and long-wavelength absorption maxima in the methoxy derivative was larger and the emission band was red shifted in comparison with the methyl derivative. Chemical and photochemical oxidation of the prepared amines gives unstable nitroxides. High intramolecular quenching was observed in polymer matrix after photochemical oxidation of the amines.
ABSTRACT A range of cinnamic units containing 4,5-dihydrooxazoles was prepared using two differen... more ABSTRACT A range of cinnamic units containing 4,5-dihydrooxazoles was prepared using two different synthetic routes. The first method was based on the transformation of substituted cinnamic or benzoic acids to 2-styryl-4,5-dihydrooxazoles. Several derivatives containing phenolic groups were prepared in this manner. The second approach consisted of a reaction between the 4,5-dihydrooxazole moiety and double bond-containing compounds. These compounds contain two or more reactive centres capable of providing polymerisations and also organic reactions.
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