RESUMO
Synthesis of an alpha,beta-alkyl branched polyester, i.e., poly(2-methyl-3-hydroxyoctanoate), has been accomplished via anionic polymerization of alpha-methyl-beta-pentyl-beta-propiolactone mediated by supramolecular complexes of potassium methoxide or potassium hydroxide, respectively. The structure of resulting polymers has been established by electrospray ionization multistage mass spectrometry (ESI-MSn), FT-IR, NMR, and GPC analyses. Previously proposed addition-elimination mechanism of the polymerization of beta-lactones containing alpha-hydrogen by alkoxide anion has been confirmed to operate also in the case of beta-lactone having alkyl substituents in both alpha and beta positions.
Assuntos
Poliésteres/síntese química , Métodos , Estrutura Molecular , Poliésteres/química , Propiolactona/análogos & derivados , Propiolactona/química , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Syntheses of biomimetic low-molecular weight poly-(R)-3-hydroxybutanoate mediated by three types of supramolecular catalysts are presented. The utility of these synthetic polyesters for preparation of artificial channels in phospholipid bilayers capable of sodium and calcium ion transport across cell membranes, is discussed. Further studies on possible applications of these bio-polymers for manufacturing drugs of prolonged activity are under way.
Assuntos
Poliésteres/química , Membrana Celular/metabolismo , Transporte de Íons , Bicamadas Lipídicas , Mimetismo Molecular , Fosfolipídeos/químicaRESUMO
Novel feasibility of fuctionalized poly(3-hydroxybutanoic acid), PHB, and its copolymers synthesis via ring-opening of beta-butyrolactone (ROP) mediated by activated anionic initiators or enzymes in vitro is presented. Using these new synthetic approaches, PHB with defined chemical structure of the end groups as well as block, graft and random copolymers have been obtained and characterized by IR, NMR, ESI-MS and GPC techniques. The relationship between the structure and properties of the novel polymeric materials prepared is discussed.
Assuntos
Hidroxibutiratos/síntese química , Poliésteres/síntese química , 4-Butirolactona/análogos & derivados , Biodegradação Ambiental , Hidroxibutiratos/química , Hidroxibutiratos/metabolismo , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Poliésteres/química , Poliésteres/metabolismo , Espectrometria de Massa de Íon Secundário , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Cytostatic activity of newly synthesized aziridinyl substituted cyclophosphazenes was tested in two in vitro systems. First, the compounds were tested by total cell protein inhibition test on human KB tumor cell line. Selected active compounds were tested in a clonogenic assay on murine L1210 leukemia cells. Out of 18 compounds tested, 12 were newly synthesized, 3 were their substrates and 4 were compounds with known cytostatic activity, used as a positive controls. Four of the newly synthesized compounds, designated with symbols: BANF-4Az, BBNF-4Az. T-oFDA-Az and W-10 revealed cytostatic activity for KB cells (ED50 = 3.4-19 micrograms/mL) and were tested in clonogenic assay. One of these compounds, namely T-oFDA-Az was subsequently selected for the further steps of screening for antitumor activity in animal tumor models.
