Synthesis and muscarinic cholinergic receptor affinities of 3-quinuclidinyl .alpha.-(alkoxyalkyl)-.alpha.-aryl-.alpha.-hydroxyacetates
摘要:
Seven analogues of 3-quinuclidinyl benzilate (QNB) in which one phenyl ring was replaced by an alkoxyalkyl moiety were synthesized and their affinities for the muscarinic cholinergic receptor determined. An oxygen in the beta-position of the moiety was not well-tolerated. By contrast, an oxygen in the gamma-position did not change the affinity for the muscarinic receptor. However, when a bromine was placed on the remaining phenyl ring, the affinity was significantly reduced in striking contrast to results obtained on halogenation of QNB.
Additive‐Free Isomerization of Allylic Alcohols to Ketones with a Cobalt PNP Pincer Catalyst
作者:Brian Spiegelberg、Andrea Dell'Acqua、Tian Xia、Anke Spannenberg、Sergey Tin、Sandra Hinze、Johannes G. de Vries
DOI:10.1002/chem.201901148
日期:2019.6.12
Catalyticisomerization of allylic alcohols in ethanol as a green solvent was achieved by using air and moisture stable cobalt (II) complexes in the absence of any additives. Under mild conditions, the cobalt PNP pincer complex substituted with phenyl groups on the phosphorus atoms appeared to be the most active. High rates were obtained at 120 °C, even though the addition of one equivalent of base
Cu-Catalyzed Sequential Dehydrogenation–Conjugate Addition for β-Functionalization of Saturated Ketones: Scope and Mechanism
作者:Xiaoming Jie、Yaping Shang、Xiaofeng Zhang、Weiping Su
DOI:10.1021/jacs.6b01337
日期:2016.5.4
The first copper-catalyzed direct β-functionalization of saturatedketones is reported. This protocol enables diverse ketones to couple with a wide range of nitrogen, oxygen and carbon nucleophiles in generally good yields under operationally simple conditions. The detailed mechanistic studies including kinetic studies, KIE measurements, identification of reaction intermediates, EPR and UV-visible
Unveiling the Reactivity of Propargylic Hydroperoxides under Gold Catalysis
作者:Benito Alcaide、Pedro Almendros、M. Teresa Quirós、Ramón López、María I. Menéndez、Aleksandra Sochacka-Ćwikła
DOI:10.1021/ja3108966
日期:2013.1.16
Controlled gold-catalyzed reactions of primary and secondary propargylic hydroperoxides with a variety of nucleophiles including alcohols, phenols, 2-hydroxynaphthalene-1,4-dione, and indoles allow the direct and efficientsynthesis of β-functionalized ketones. Moreover, the utility of some of the resulting products for the selective preparation of fused polycycles has been demonstrated. In addition
伯和仲炔丙基氢过氧化物与各种亲核试剂(包括醇、酚、2-羟基萘-1,4-二酮和吲哚)的受控金催化反应允许直接有效地合成 β-官能化酮。此外,已经证明了一些所得产物用于选择性制备稠合多环的效用。此外,还进行了密度泛函理论 (DFT) 计算和 (18) O 标记实验,以深入了解炔丙基氢过氧化物与外部亲核试剂在金催化下的受控反应性的各个方面。
Elimination and addition reactions. Part 30. Leaving group abilities in alkene-forming eliminations activated by sulphonyl groups
作者:Donald R. Marshall、Patsy J. Thomas、Charles J. M. Stirling
DOI:10.1039/p29770001898
日期:——
Rates of elimination of the group Z from a series of β-substituted sulphones, PhSO2·CH2·CH2Z, in ethanolic sodium ethoxide at 25 °C have been measured. For each substrate, the mechanism of the reaction has been shown to be the reversible carbanion mechanism [(E1cB)R] by determination of the primary kinetic deuterium isotope effect or by demonstration that deuterium-hydrogen exchange at Cβ is very much
A new protocol for the deoxygenation of alcohols and the hydrogenation of alkenes under Brønsted acid catalysis has been developed. The method is based on the use of either a benzyl or isopropyl ether as a tracelesshydrogen‐atom donor, and involves an intramolecular hydride transfer as a key step, which is achieved in a regio‐ and stereoselective manner.