3430-16-8Relevant articles and documents
A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
Taylor, Nicholas P.,Gonzalez, Jorge A.,Nichol, Gary S.,García-Domínguez, Andrés,Leach, Andrew G.,Lloyd-Jones, Guy C.
supporting information, p. 721 - 729 (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.
NaBH4-TMEDA and a palladium catalyst as efficient regio- and chemoselective system for the hydrodehalogenation of halogenated heterocycles
Chelucci, Giorgio,Figus, Susanna
, p. 191 - 209 (2014/07/21)
The pair NaBH4-TMEDA as hydride source and a palladium catalyst in THF prove to be an efficient system for the hydrodehalogenation of halogenated heterocycles with one or more heteroatoms. In general, Pd(OAc) 2-PPh3 rapidly hydrodehalogenates reactive halo-heterocycles such as bromo-pyridines, -quinolines, -thiophenes, -indoles, -imidazoles, etc., at room temperature in very good yields, whereas in most cases PdCl2(dppf) reduces less reactive halides such as chloro-pyridines, -quinolines, -pyrimidines and bromo-indoles, -benzofurans, etc. Moreover, PdCl2(tbpf) shows to be even more active removing the 2- and 5-chlorine from both thiophene and thiazole rings. The reaction conditions tolerate various functional groups, allowing highly chemoselective reactions in the presence of halide, ester, alkyne, alkene and nitrile substituents. Moreover, with a proper selection of the catalyst it is also possible to obtain a good control in the regioselective hydrodehalogenation of a variety of polyhalogenated substrates.
ANTIBACTERIAL AGENTS
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Page/Page column 76, (2010/11/28)
Compounds of formula (I) have antibacterial activity wherein R represents hydrogen or 1, 2 or 3 optional substituents; W is =C(R1)- or =N-; R1 is hydrogen or an optional substituent and R2 is hydrogen, methyl, or fluorine; or R1 and R2 taken together are -CH2-, -CH2CH2-, -O-, or, in either orientation, -O- CH2- Or -OCH2CH2-; R3 is a radical of formula -(Alk1)m-(Z)p-(Alk2)n-Q wherein m, p and n are independently 0 or 1, provided that at least one of m, p and n is 1, Z is -O-, -S-, -S(O)-, -S(O2)-, -NH-, -N(CH3)-, -N(CH2CH3)-, -C(=O)-, -O-(C=O)-, -C(=O)-O-, or an optionally substituted divalent monocyclic carbocyclic or heterocyclic radical having 3 to 6 ring atoms; or an optionally substituted divalent bicyclic heterocyclic radical having 5 to 10 ring atoms; Alk1 and Alk2 are optionally substituted C1C6 alkylene, C2-C6 alkenylene, or C2-C6 alkynylene radicals, which may optionally terminate with or be interrupted by -O-, -S-, -S(O)-, -S(O2)-, -NH-, -N(CH3)-, or -N(CH2CH3)-; and Q is hydrogen, halogen, nitrile, or hydroxyl or an optionally substituted monocyclic carbocyclic or heterocyclic radical having 3 to 6 ring atoms; or an optionally substituted bicyclic heterocyclic radical having 5 to 10 ring atoms.
