20697-05-6Relevant academic research and scientific papers
Clues to the development of mechanism-based inactivators of 3α-hydroxysteroid dehydrogenase: Comparison of steroidal and nonsteroidal Michael acceptors and epoxides
Penning, Trevor M.,Thornton, Rosemary,Ricigliano, Joseph W.
, p. 420 - 427 (1991)
A series of steroidal and nonsteroidal Michael acceptors that represent reaction products for 3α-hydroxy steroid dehydrogenase were synthesized and evaluated as potential enzyme-generated inactivators. Introduction of exocyclic olefins either at C-2 or C-6 produced inhibitors with high affinity for the enzyme (0.05 to 5.0 ·M). However, despite this affinity, none of these compounds produced time-dependent inactivation of the enzyme. By contrast, analogs based on 1-phenyl-2-propen-1-one were stoichiometric inactivators of the enzyme and ease of turnover of the parent latent Michael acceptor depended on the presence of an electron-withdrawing substituent at the para position. A series of steroidal and nonsteroidal epoxides in which the oxiranyl oxygen could be substituted for the 3-ketone (the acceptor carbonyl of a steroid substrate) were also synthesized and evaluated as potential mechanism-based inactivators. Steroidal 2α,3α-, and 3α,4α-epoxides as well as 3α- and 3β-spiroepoxides did not bind to the enzyme and were unable to cause enzyme inactivation in either the presence or absence of pyridine nucleotide. In contrast, nitrostyrene oxides produced time-dependent inactivation, the rate of which was governed by the presence of an electron withdrawing group at the para position. These data indicate that the design of mechanism-based inactivators for 3α-hydroxysteroid dehydrogenase requires the incorporation of electron-withdrawing groups adjacent to the latent enzyme-activated group and, as a result, the turnover and/or reactivity of these compounds is increased. Moreover, these compounds can be modeled on nonsteroids. (Steroids56:420-427, 1991).
Suppression of morphine and cocaine self-administration in rats by a mixed mu antagonist-kappa agonist (N-CBM-TAMO) and a long-acting selective D1 antagonist (AS-300)
Archer, Sydney,Glick, Stanley D.,Maisonneuve, Isabelle M.,Bidlack, Jean M.,Xu, Jimmy Y.,Teitler, Milt,Sebastian, Alice,El-Hamouly, Wageeh,Hutchinson, Ian
, p. 1139 - 1144 (1996)
N-CBM-TAMO 2 was prepared by the same procedure as used for TAMO 1. It was found to be a short-term kappa agonist and a long-term mu antagonist. The benzazepine 12, (AS-300) was a potent selective D1 antagonist. Both compounds suppressed cocaine and morphine self-administration in rats at doses which did not affect water consumption.
Pd(II) anchored to modified Fe3O4 nanoparticles as a new magnetically recoverable catalyst for epoxidation of styrene
Keshipour, Sajjad,Khalteh, Nastaran Kalam
, p. 1977 - 1982 (2016)
A new support for Pd(II) was synthesized via the functionalization of Fe3O4 nanoparticles with N-(2-aminoethyl)acetamide. PdCl2 was anchored to the support for obtaining a heterogeneous magnetically recoverable catalyst fo
Synthesis of a light-harvesting ruthenium porphyrin complex substituted with BODIPY units. Implications for visible light-promoted catalytic oxidations
Malone, Jonathan,Klaine, Seth,Alcantar, Christian,Bratcher, Fox,Zhang, Rui
, p. 4977 - 4985 (2021/03/26)
A light-harvesting ruthenium porphyrin substituted covalently with four boron-dipyrrin (BODIPY) moieties has been synthesized and studied. The resulting complex showed an efficient decarbonylation reaction predominantly due to a photo-induced energy transfer process. Chemical oxidation of the ruthenium(ii) BODIPY-porphyrin afforded a high-energytrans-dioxoruthenium(vi) species that is one order of magnitude more reactive towards alkene oxidation than those analogues supported by conventional porphyrins. In the presence of visible light, the ruthenium(ii) BODIPY-porphyrin displayed remarkable catalytic activity toward sulfide oxidation and alkene epoxidation using iodobenzene diacetate [PhI(OAc)2] and 2,6-dichloropyridineN-oxide (Cl2pyNO) as terminal oxidants, respectively. The findings in this work highlight that porphyrin-BODIPY conjugated metal complexes are potentially useful for visible light-promoted catalytic oxidations.
Reprogramming Epoxide Hydrolase to Improve Enantioconvergence in Hydrolysis of Styrene Oxide Scaffolds
Li, Fu-Long,Qiu, Yan-Yan,Zheng, Yu-Cong,Chen, Fei-Fei,Kong, Xu–Dong,Xu, Jian-He,Yu, Hui-Lei
supporting information, p. 4699 - 4706 (2020/09/21)
Enantioconvergent hydrolysis by epoxide hydrolase is a promising method for the synthesis of important vicinal diols. However, the poor regioselectivity of the naturally occurring enzymes results in low enantioconvergence in the enzymatic hydrolysis of styrene oxides. Herein, modulated residue No. 263 was redesigned based on structural information and a smart variant library was constructed by site-directed modification using an “optimized amino acid alphabet” to improve the regioselectivity of epoxide hydrolase from Vigna radiata (VrEH2). The regioselectivity coefficient (r) of variant M263Q for the R-isomer of meta-substituted styrene oxides was improved 40–63-fold, and variant M263V also exhibited higher regioselectivity towards the R-isomer of para-substituted styrene oxides compared with the wild type, which resulted in improved enantioconvergence in hydrolysis of styrene oxide scaffolds. Structural insight showed the crucial role of residue No. 263 in modulating the substrate binding conformation by altering the binding surroundings. Furthermore, increased differences in the attacking distance between nucleophilic residue Asp101 and the two carbon atoms of the epoxide ring provided evidence for improved regioselectivity. Several high-value vicinal diols were readily synthesized (>88% yield, 90%–98% ee) by enantioconvergent hydrolysis using the reprogrammed variants. These findings provide a successful strategy for enhancing the enantioconvergence of native epoxide hydrolases through key single-site mutation and more powerful enzyme tools for the enantioconvergent hydrolysis of styrene oxide scaffolds into single (R)-enantiomers of chiral vicinal diols. (Figure presented.).
Visible-light assisted of nano Ni/g-C3N4 with efficient photocatalytic activity and stability for selective aerobic C?H activation and epoxidation
Akrami, Zahra,Hosseini-Sarvari, Mona
supporting information, (2020/10/13)
A selective, economical, and ecological protocol has been described for the oxidation of methyl arenes and their analogs to the corresponding carbonyl compounds and epoxidation reactions of alkenes with molecular oxygen (O2) or air as a green oxygen source, under mild reaction conditions. The nano Ni/g-C3N4 exhibited high photocatalytic activity, stability, and selectivity in the C?H activation of methyl arenes, methylene arenes, and epoxidation of various alkenes under visible- light irradiation without the use of an oxidizing agent and under base free conditions.
Remarkable increase in the rate of the catalytic epoxidation of electron deficient styrenes through the addition of Sc(OTf)3 to the MnTMTACN catalyst
Nodzewska, Aneta,Watkinson, Michael
supporting information, p. 1461 - 1464 (2018/02/19)
The effect of Lewis acids on the catalytic activity of [Mn2(μ-O)3(TMTACN)2](PF6)2 in the epoxidation of styrenes using hydrogen peroxide as the oxidant has shown that the addition of Sc(OTf)3 at low catalytic loading results in a very significant increase in the efficiency of the catalyst and a reduction of the reaction time to only 3 minutes in most cases.
Montmorillonite K10 catalyzed highly regioselective azidolysis of epoxides: A short and efficient synthesis of phenylglycine
Ch Ghosh, Keshab,Banerjee, Isita,Sinha, Surajit
supporting information, p. 2923 - 2934 (2018/12/04)
A series of β‐hydroxyazides were effectively synthesized from the regioselective ring opening of epoxides by sodium azide using montmorillonite K10 as a novel heterogeneous catalyst in aqueous acetonitrile in good to excellent yields. The utility of this method has been demonstrated by achieving a short synthesis of phenylglycine in 33.5% overall yield.
Stable Copper Nanoparticle Photocatalysts for Selective Epoxidation of Alkenes with Visible Light
Huang, Yiming,Liu, Zhe,Gao, Guoping,Xiao, Gang,Du, Aijun,Bottle, Steven,Sarina, Sarina,Zhu, Huaiyong
, p. 4975 - 4985 (2017/08/17)
Selective epoxidation of various alkenes with molecular oxygen (O2) under mild conditions is a longstanding challenge in achieving syntheses of epoxides. Cu-based catalysts have been found to be catalytically active for selective epoxidations. However, the application of copper nanoparticles (CuNPs) for photocatalyzed epoxidations is encumbered by the instability of CuNPs in air. Herein we report that CuNPs supported on titanium nitride (TiN) without additional stabilizers not only are stable in air but also can catalyze selective epoxidation of various alkenes with O2 or even air as a benign oxidant under light irradiation. CuNPs remain in the metallic state due to the significant charge transfer that occurs between CuNPs and TiN. The epoxidation is driven by visible light irradiation at moderate temperatures, achieving good to high yields and excellent selectivity. The photocatalytic process is applicable to the selective epoxidation of various alkenes. In this photocatalytic system, reactant alkenes chemically adsorb on CuNPs, forming Cu-alkene surface complexes, and light irradiation can activate the complexes for reaction. The cyclic ether solvent also plays a key role, reacting with O2 on the surface of CuNPs under light irradiation, yielding oxygen adatoms. The activated surface complexes react with the adatoms, yielding the corresponding epoxides. Analysis of the influence of irradiation wavelength and intensity on the epoxidation suggests that light-excited electrons of CuNPs drive the reaction. The adatoms formed react with alkenes, producing the final product epoxides. We also observed interesting product stereoselectivity, predominantly generating the trans isomers for the epoxidation of stilbene (up to 97%). The findings reported here not only provide an effective and selective reaction system for alkene epoxidations but also are a step toward demonstrating the practical use of CuNPs as photocatalysts for various applications.
Substrate ionization energy influences the epoxidation of m-substituted styrenes catalyzed by chloroperoxidase from Caldariomyces fumago
Mu?oz-Guerrero, Fabio A.,águila, Sergio,Vazquez-Duhalt, Rafael,Campos, Cristian H.,Torres, Cecilia C.,Alderete, Joel B.
, p. 52 - 54 (2016/02/03)
Chloroperoxidase from the fungus Caldariomyces fumago is a versatile heme-peroxidase, which is able to catalyze olefin epoxidation. In this report, the epoxidation of m-substituted styrene catalyzed by chloroperoxidase was studied. The catalytic data fit
