Seyferth-Gilbert Homologation as a Route to<sup>18</sup>F-Labeled Building Blocks: Preparation of Radiofluorinated Phenylacetylenes and Their Application in PET Chemistry
作者:Philipp Krapf、Raphael Richarz、Elizaveta A. Urusova、Bernd Neumaier、Boris D. Zlatopolskiy
DOI:10.1002/ejoc.201501377
日期:2016.1
A convenient method for the preparation of hitherto unknown ([18F]fluorophenyl)acetylenes ([18F]FPAs) using the Seyferth–Gilberthomologation is reported. The novel buildingblocks were efficiently prepared from easily accessible [18F]fluorobenzaldehydes by using the Bestmann–Ohira reagent. High radiochemical yields and excellent radiochemical purities were achieved within only 20 min of reaction time;
Mannich‐type Reactions of Cyclic Nitrones: Effective Methods for the Enantioselective Synthesis of Piperidine‐containing Alkaloids
作者:Vladislav G. Lisnyak、Tessa Lynch‐Colameta、Scott A. Snyder
DOI:10.1002/anie.201809799
日期:2018.11.12
dozens of biologically active 2-substituted and 2,6-disubstituted piperidines, only a limited number of approaches exist for their synthesis. Herein is described two Mannich-type additions to nitrones, one using β-ketoacids under catalyst-free conditions and another using methyl ketones in the presence of chiral thioureas, which can generate a broad array of such 2-substituted materials, as well as other
作者:Herman P. Perzanowski、Said S. Al-Jaroudi、Mohamed I.M. Wazeer、Sk.Asrof Ali
DOI:10.1016/s0040-4020(97)00760-6
日期:1997.8
several cyclic nitrones afforded [n,3,0]heterobicyclicalkanes devoid of any substituents in the ring skeleton. These fused ring systems with a bridgehead nitrogen, capable of undergoing nitrogeninversion, allowed us to determine the stereochemistry of the ring fusion and the thermodynamic stability of the cis, trans isomers. Some of the cycloadducts on peracid induced ring opening gave a new series
Photosensitized single electron transfer oxidation of N-hydroxylamines: A convenient synthesis of cyclic nitrones
作者:G Pandey、G Kumaraswamy、A Krishna
DOI:10.1016/s0040-4039(00)96172-0
日期:1987.1
Photolysis of N-hydroxylamines of type in the presence of 1,4-dicyanonaphthalene (DCN) as an electron acceptor gave high yields of nitrones . Crude nitrones have been trapped by 1,3-dipolar cycloaddition reaction with dimethyl fumarate. Mechanistic pathways have also been discussed.