Synthesis of N-(2-(Methylamino)ethyl) Derivatives of 2H-Phthalazin-1-ones

A series of new alkyl, tosyl, acetyl, and tert-butoxycarbonyl derivatives of 2-(2-aminoethyl)-phthalazinones were efficiently synthesized by reaction of lactams with N-Boc-, N-acetyl-, or N,O-ditosyl derivatives of N-methylethanolamine in the presence of MeONa or under Mitsunobu reaction conditions. Selected compounds were converted into corresponding 2-[2-(methylamino)ethyl]phthalazinones in good yields.     

A comparative analysis of mass losses of some aliphatic polyesters upon enzymatic degradation

Results of investigation of mass losses, geometrical surface structure changes and variations in crystallinity of poly(lactic acid) (PLA), poly(?-caprolactone) (PCL) and commercially available material (PHB) consisting of poly(3,4-hydroxybutyrate) and poly(lactic acid) are presented. These structural changes occurred due to degradation of these polymers in the presence of the following enzymes: proteinase K, protease, esterase or lipase. Independently of the enzyme type, the largest mass loss was found for PLA and the smallest for PHB. Thus, under the experimental conditions, the processes of enzymatic degradation proceeded most rapidly in PLA, more slowly in PCL, and the most slowly in PHB. It was also found that proteinase K caused the largest mass losses, protease caused smaller mass losses, and both esterase and lipase produced the least mass losses, while lipase did not bring about mass loss in PHB. Images of surfaces of individual samples, obtained by scanning electron microscopy (SEM), indirectly confirmed the results of the mass loss examination. Crystallinity of the studied polyesters increased with degradation in the presence of proteinase K and protease, while changes in the crystallinity due to esterase and lipase were not observed. The presented results illustrate well the relative susceptibilities of the individual polyesters toward degradation induced by various enzymes.     

Changes of 1,2,4-Triazole Retention and Lipophilicity Descriptor Values in RP-TLC and MLC–TLC Systems in the Presence of an External Magnetic Field

JPC – Journal of Planar Chromatography – Modern TLC - As it was shown in earlier experiments, magnetic field can influence various processes taking part in nature. One of them might be...     

Automatic window factor analysis—A more efficient method for determining concentration profiles from evolutionary spectra

An algorithm called automatic window factor analysis (AUTOWFA) is developed for the purpose of determining, efficiently and automatically, the concentration profiles of the spectroscopically active components present in evolutionary processes, such as chemical titration, chromatography and kinetics. The method not only yields windows and profiles in agreement with those reported in the literature, but also reveals components not detected by precursor techniques. The method, however, has not been optimized and may require user interaction to fine-tune the windows.