2304-94-1Relevant articles and documents
A remarkable enhancement of selectivity towards versatile analytes by a strategically integrated H-bonding site containing phase
Mallik, Abul K.,Qiu, Hongdeng,Kuwahara, Yutaka,Takafuji, Makoto,Ihara, Hirotaka
, p. 14243 - 14246 (2015)
A double β-alanylated l-glutamide-derived organic phase has been newly designed and synthesized in such a way that integrated H-bonding (interaction) sites make it very suitable for the separation of versatile analytes, including shape-constrained isomers, and nonpolar, polar and basic compounds. The β-alanine residues introduced into two long-chain alkyl group moieties provide ordered polar groups through H-bonding among the amide groups.
Dioxygen activation with molybdenum complexes bearing amide-functionalized iminophenolate ligands
Zwettler, Niklas,Ehweiner, Madeleine A.,Schachner, J?rg A.,Dupé, Antoine,Belaj, Ferdinand,M?sch-Zanetti, Nadia C.
, (2019/05/24)
Two novel iminophenolate ligands with amidopropyl side chains (HL2 and HL3) on the imine functionality have been synthesized in order to prepare dioxidomolybdenum(VI) complexes of the general structure [MoO2L2] featuring pendant internal hydrogen bond donors. For reasons of comparison, a previously published complex featuring n-butyl side chains (L1) was included in the investigation. Three complexes (1-3) obtained using these ligands (HL1-HL3) were able to activate dioxygen in an in situ approach: The intermediate molybdenum(IV) species [MoO(PMe3)L2] is first generated by treatment with an excess of PMe3. Subsequent reaction with dioxygen leads to oxido peroxido complexes of the structure [MoO(O2)L2]. For the complex employing the ligand with the n-butyl side chain, the isolation of the oxidomolybdenum(IV) phosphino complex [MoO(PMe3)(L1) 2] (4) was successful, whereas the respective Mo(IV) species employing the ligands with the amidopropyl side chains were found to be not stable enough to be isolated. The three oxido peroxido complexes of the structure [MoO(O2)L2] (9-11) were systematically compared to assess the influence of internal hydrogen bonds on the geometry as well as the catalytic activity in aerobic oxidation. All complexes were characterized by spectroscopic means. Furthermore, molecular structures were determined by single-crystal X-ray diffraction analyses of HL3, 1-3, 9-11 together with three polynuclear products {[MoO(L2) 2]2 (μ-O)} (7), {[MoO(L2)] 4 (μ-O) 6} (8) and [C9H13N2O]4 [Mo8O26] 6OPMe3 (12) which were obtained during the synthesis of reduced complexes of the type [MoO(PMe3)L2] (4-6).
Chloroperoxidase-catalyzed amino alcohol oxidation: Substrate specificity and novel strategy for the synthesis of N-Cbz-3-aminopropanal
Masdeu, Gerard,Pérez-Trujillo, Míriam,López-Santín, Josep,álvaro, Gregorio
, p. 1204 - 1211 (2016/08/09)
The ability of chloroperoxidase (CPO) to catalyze amino alcohol oxidations was investigated. The oxidations of compounds with different configurations with respect to the amine position towards hydroxyl – using H2O2 and tert-butyl hydroperoxide (t-BuOOH) – were analyzed in terms of the initial reaction rate, substrate conversion, and CPO operational stability. It was observed that the further the amino group from the hydroxyl, the lower the initial reaction rate. The effect of the amino-protecting group and other substituents (i.e., methyl and hydroxyl) was also examined, revealing an increase in steric hindrance due to the effect of bulky substituents. The observed reaction rates were higher with t-BuOOH, whereas CPO was more stable with H2O2. Moreover, CPO stability had to be determined case by case as the enzyme activity was modulated by the substrate. The oxidation of N-Cbz-3-aminopropanol (Cbz, carboxybenzyl) to N-Cbz-3-aminopropanal was investigated. Main operational conditions such as the reaction medium, initial amino alcohol concentration, and peroxide nature were studied. The reaction kinetics was determined, and no substrate inhibition was observed. By-products from a chemical reaction between the formed amino aldehyde and the peroxide were identified, and a novel reaction mechanism was proposed. Finally, the biotransformation was achieved by reducing side reactions and identifying the key factors to be addressed to further optimize the product yield.