Jolanta Maślińska-Solich

Condensation and Polycondensation of Terephthaldehyde with Methyl D-Hexopyranosides

The condensation and polycondensations of terephthaldehyde (1) and methyl D-hexopyranosides (gluco-, galacto- and mannopyranoside) are described. Methyl α-D-glucopyranoside and methyl α-D-galactopyranoside react with 1 to give mono-5 a and 6 a and diacetals 5 b and 6 b. Their structures were confirmed by NMR and IR spectroscopy. The polycondensation of methyl α-D-mannopyranoside (4) with 1 was studied in various solvents within the temperature range of 80–140°C. Regardless of the conversion or the initial comonomer feed ratios the composition of polycondensates depended on the reaction conditions leading to the formation of materials with diverse solubilities, molecular weights and optical properties. The regioselective polycondensation of 1 and 4 was examined by the 1H NMR spectroscopy of polymer 7. In the case of five-membered cyclic acetal units, mixtures of the endo-H and exo-H dioxolan-2-yl system diastereomers are formed. Experimental examples of functionalization via ester units in polymer molecules 8 are described and the efficiency of the reaction routes and procedures are evaluated. The molecular weight was estimated by size-exclusion chromatography (SEC) measurements before and after the functionalization.

The effect of polymer-supported reagent structure on the oxidation of cyclic acetals

Abstract The bromination of diacetals of terephthalaldehyde and glutaraldehyde by means of polymeric brominating reagents (PBR), poly( N -bromoacrylamide), copoly( N -bromomaleimide(amide)-limonene) and poly( N -bromomethacrylamide) - Amberlite IRC-50 Br, was described. The bromination by PBR is more specific than that by 1,3-dibromo-5,5-dimethylhydantoin (DBDW. The reactivity of -NHBr groups in the oxidation of acetals is considerably influenced by -COOH groups present in the backbone of PBR.

The configuration effect of some cyclic acetals on the rate of oxidation by polymeric complex of Co(II)

Cobalt(II) bound to copolymer of maleic acid and ethyl vinyl ether, crosslinked with 10 mol% 1,6-hexamethylenediamine was found to catalyze the oxidation of 2-styryl-1,3-dioxane and its alkyl substituted derivatives as well as 4,5-dimethyl-2-styryl-1,3-dioxolane affording hydroxy-alkyl-cinnamates. The effect of polymeric Co(II) complex on the regioselectivity of the oxidation of 4-methyl-2-styryl-1,3-dioxane and cis-syn 4,5-dimethyl-2-styryl-1,3-dioxolane was observed. A free-radical mechanism is proposed.