110-68-9Relevant articles and documents
Electron Transfer on the Photodehalogenation of 2-(4-chlorophenyl)benzoxazole Assisted by Amines
Fery-Forgues, Suzanne,Lavabre, Dominique,Paillous, Nicole
, p. 3381 - 3386 (1987)
The photochemical reactivity of 2-(4-chlorophenyl)benzoxazole in the presence of a series of amines has been investigated.A fluorescence quenching study provides evidence for the formation of an exciplex between the singlet excited state of the benzoxazole derivative and the amine in its ground state.This exciplex gives rise to a charge-transfer complex (CTC).The quenching fluorescence date can be fitted by a Weller-Marcus system, thus leading to large reorganization energies.The measurment of dehalogenation, which is drastically increased in the presence of amines, allowed us to estimate the reactivity of the CTC.In the case of tertiary amines, 1percent of the CTC formed via the singlet state leads to the dehalogenation.For secondary amines a hydrogen transfer between the amine and the excited triplet state of the chloro compound is also postulated.
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Graymore
, p. 1353,1356 (1932)
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Blundell,Graymore
, p. 1787 (1939)
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A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
supporting information, (2022/01/04)
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
Photometric Characterization of the Reductive Amination Scope of the Imine Reductases from Streptomyces tsukubaensis and Streptomyces ipomoeae
Matzel, Philipp,Krautschick, Lukas,H?hne, Matthias
, p. 2022 - 2027 (2017/10/07)
Imine reductases (IREDs) have emerged as promising enzymes for the asymmetric synthesis of secondary and tertiary amines starting from carbonyl substrates. Screening the substrate specificity of the reductive amination reaction is usually performed by time-consuming GC analytics. We found two highly active IREDs in our enzyme collection, IR-20 from Streptomyces tsukubaensis and IR-Sip from Streptomyces ipomoeae, that allowed a comprehensive substrate screening with a photometric NADPH assay. We screened 39 carbonyl substrates combined with 17 amines as nucleophiles. Activity data from 663 combinations provided a clear picture about substrate specificity and capabilities in the reductive amination of these enzymes. Besides aliphatic aldehydes, the IREDs accepted various cyclic (C4–C8) and acyclic ketones, preferentially with methylamine. IR-Sip also accepted a range of primary and secondary amines as nucleophiles. In biocatalytic reactions, IR-Sip converted (R)-3-methylcyclohexanone with dimethylamine or pyrrolidine with high diastereoselectivity (>94–96 % de). The nucleophile acceptor spectrum depended on the carbonyl substrate employed. The conversion of well-accepted substrates could also be detected if crude lysates were employed as the enzyme source.
Selective N-methylation of aliphatic amines with CO2 and hydrosilanes using nickel-phosphine catalysts
Gonzlez-Sebastin, Lucero,Flores-Alamo, Marcos,Garca, Juventino J.
, p. 763 - 769 (2015/05/12)
A method using CO2 and PhSiH3 for the methylation of primary and secondary aliphatic amines catalyzed by Ni (0) complexes was developed, selectively producing the monomethylated products in moderate to good yields. For that purpose, two catalysts were used: [(dippe)Ni(μ-H)]2 and the commercially available Ni(COD)2/dcype, both of which were rather efficient in this process. With a slight experimental modification, the reaction allowed the production of monomethylated ureas in good yields by using low amounts of PhSiH3. On the basis of the experimental results, we propose a possible reaction mechanism for the formation of the new C-N bond.
