Jozef Lustoň

Synthesis and bioimmunological efficiency of poly(2-oxazolines) containing a free amino group

Novel amphiphilic copolymers on the basis of 2-oxazolines containing a free amino group were prepared. The copolymers were synthesized by the living cationic polymerization of 2-ethyl-2-oxazoline (ETOX) and 2-(4-aminophenyl)-2-oxazoline (APOX). The main goal of this work was the synthesis of water soluble polymer material with the defined number of functional groups necessary for the attachment of proteins and polysaccharides. A high concentration of free amino groups allows immobilization of various biosubstances, e.g. drugs, proteins or polysaccharides. Thermal properties have been studied with respect to the composition of the copolymers. Cytotoxicity and the bioimmunological efficiency of the selected copolymer were studied.

Immunomodulatory efficiency of poly(2-oxazolines)

Poly(2-oxazolines) represent promising polymer materials for biomedical applications. The activation of mouse lymphoid macrophage line P388.D1 (clone 3124) by two selected representatives of poly(2-oxazolines), namely poly(2-ethyl-2-oxazoline) (PETOX100) and poly[2-(4-aminophenyl)-2-oxazoline-co-2-ethyl-2-oxazoline] (AEOX10), was assessed in vitro. The immunomodulatory efficacy of both polymers was evaluated via the induced release of pro-inflammatory cytokines (TNF-α, IL-1α and IL-6) and the acceleration of reactive free radicals. The present study revealed effective structure-immunomodulating associations of AEOX10 and PETOX100, which are desirable in biomedical and pharmaceutical applications of aliphatic and aromatic poly (2-oxazolines) in vivo.

2‐Oxazoline‐Terminated Polystyrene by Atom‐Transfer Radical Polymerization

Macromonomers of polystyrene containing one functional 1,3-oxazoline end group were obtained by atom-transfer radical polymerization (ATRP) using oxazoline-containing initiators. 2-(1-Bromoethyl)-1,3-oxazoline (2b) and 2-(4-(1-bromoethyl)phenyl)-1,-oxazoline (6) were prepared for this purpose. 2-(1-Bromoethyl)-1,3-oxazoline was prepared by the bromination of 2-ethyl-1,3-oxazoline with N-bromosuccinimide (NBS). 2-(4-(1-Bromoethyl)phenyl)-1,3-oxazoline was obtained by the treatment of 4-(1-bromoethyl) benzoic acid with ethanolamine and subsequent cyclization with SOC1 2 . Both initiators proved to be suitable for the ATRP of styrene. Oxazoline mono-terminated polystyrenes with Mn between 2 000 and 3 500 G . mol -1 were obtained. The oxazoline groups were observed in the NMR spectra

Azo-group labelled polyesters by end-capping with 2-oxazoline derivatives - preparation

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.

Azo‐group labelled polyesters by end‐capping with 2‐oxazoline derivatives – photochemical properties

Two azobenzene containing 2-oxazolines were used for labeling of a polyester with carboxylic end groups by the end-capping method. The modification was performed under the conditions of either reactive processing or in a solution. Photochemical activity of the prepared polymers, as well as that of the modifiers was studied. The polymers prepared represent new photosensitive materials that undergo photochemical trans-cis isomerizations and reverse cis-trans reactions.

Unsaturated 2-oxazoline end capping of liquid crystalline polyester by reactive processing and in a solution

End capping of liquid crystalline poly(ethylene terephthalate-co-oxybenzoate) with a bifunctional 2-oxazoline derivative, 2-(4-allyloxyphenyl)-2-oxazoline, has been performed in melt under the condition of reactive processing and in a solution. The reaction in melt is very fast and, despite some modifier evaporation, it is completed in 2 min at 230°C. The product is a polyester containing unsaturated end groups bonded via esteramide linkage. The presence of unsaturation was proved by 13C-NMR spectroscopy. An increase in temperature and prolongation of the processing time gives raise to thermal-induced reactions on the unsaturated end groups, resulting in an increase of the glass transition temperature. Depending on the processing temperature decomposition, propagation and crosslinking occur in different extent and influence polymer properties.

Synthesis and Polymerization Reactions of Cyclic Imino Ethers. 4. Aromatic Poly(ester amide)s of the AA+BB Type on the Basis of 2-Oxazolines

Poly(ester amide)s were prepared by thermally initiated polymerization from two aromatic bis(2-oxazoline)s and four aromatic dicarboxylic acids. Polymerizations were performed in bulk and in solution. The structure of the polymers formed was confirmed by spectral analysis. The synthesis is limited by the thermal stability of the starting compounds. Limitation of the solution polymerization is the solubility of the starting compounds and the products in the solvent used. The prepared polymers have very good thermal properties.

New materials with high π conjugation by reaction of 2‐oxazoline containing phenols with polyamidines and inorganic base

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.

Synthesis of bis-2-oxazolines containing inner unsaturation and their hydrolysis to phenylenediacrylic acids

_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.

Synthesis of cinnamic acid-derived 4,5-dihydrooxazoles

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.