Kinetics of Petroleum Resin Epoxidation by Peracetic Acid

AbstractThe in situ oxidation of the petroleum resin under soft condition was investigated. The oxidation was carried out by using hydrogen peroxide and acetic acid as the oxidants, and sulphuric acid as a catalyst for in situ formation of the peracetic acid. The infrared spectroscopy analysis shows the changes in the molecular structure: the amount of the epoxy, hydroxyl and carbonyl groups increases and the number of unsaturated bonds decreases. The new method for the determination of the reaction rate constant was presented. For the determination of the reaction rate constants the relative intensity of absorption band in the area of epoxy and carboxyl groups vibration was used. Obtained data are in a very good correlation with the reaction rate constants obtained with the epoxy and acid number valuation. That allows to conclude the validity of using presented algorithm. Kinetic calculation indicates the occurrence of the oxidation reaction by the first order. According to average reaction rate constant the process has a high selectivity for epoxy groups

Diazirine-Containing Photoactivatable Isoprenoid: Synthesis and Application in Studies with Isoprenylcysteine Carboxyl Methyltransferase

Photoaffinity labeling is a useful technique employed to identify protein–ligand and protein–protein noncovalent interactions. Photolabeling experiments have been particularly informative for probing membrane-bound proteins where structural information is difficult to obtain. The most widely used classes of photoactive functionalities include aryl azides, diazocarbonyls, diazirines, and benzophenones. Diazirines are intrinsically smaller than benzophenones and generate carbenes upon photolysis that react with a broader range of amino acid side chains compared with the benzophenone-derived diradical; this makes diazirines potentially more general photoaffinity-labeling agents. In this article, we describe the development and application of a new isoprenoid analogue containing a diazirine moiety that was prepared in six steps and incorporated into an <b>a</b>-factor-derived peptide produced via solid-phase synthesis. In addition to the diazirine moiety, fluorescein and biotin groups were also incorporated into the peptide to aid in the detection and enrichment of photo-cross-linked products. This multifuctional diazirine-containing peptide was a substrate for Ste14p, the yeast homologue of the potential anticancer target Icmt, with <i>K</i>_m (6.6 μM) and <i>V</i>_max (947 pmol min^–1 mg^–1) values comparable or better than <b>a</b>-factor peptides functionalized with benzophenone-based isoprenoids. Photo-cross-linking experiments demonstrated that the diazirine probe photo-cross-linked to Ste14p with observably higher efficiency than benzophenone-containing <b>a</b>-factor peptides

BABINE: An original and user-friendly scale for the simple and quick management of herb-drug interactions in clinical practice

info:eu-repo/semantics/publishe