Facile One-Pot Transformation of Primary Alcohols into 3-Aryl- and 3-Alkyl-isoxazoles and -pyrazoles
作者:Eiji Kobayashi、Hideo Togo
DOI:10.1055/s-0039-1690102
日期:2019.10
Abstract Various primary alcohols were smoothly transformed into 3-aryl- and 3-alkylisoxazoles in good yields in one pot by successive treatment with PhI(OAc)2 in the presence of TEMPO, NH2OH, and then NCS, followed by reaction with alkynes in the presence of Et3N. Similarly, various primary alcohols were smoothly transformed into 3-aryl- and 3-alkylpyrazoles in good yields in one pot by successive
The use of enaminones and enamines as effective synthons for MSA-catalyzed regioselective synthesis of 1,3,4-tri- and 1,3,4,5-tetrasubstituted pyrazoles
In the present work, an efficient regioselectivesynthesis of 1,3,4-tri- and 1,3,4,5-tetrasubstituted pyrazoles via a methanesulfonic acid (MSA)-catalyzed reaction of hydrazones with enaminones or enamines is reported. Mechanistically, the formation of the title compounds involves the [2+3] cycloaddition of hydrazones with enaminones or enamines followed by aromatization with acid and oxygen. This
cycloaddition of nitrile imines with 3-alkenyl-oxindoles was catalyzed by a new chiral Mg(ClO4)2 complex of an N,N′-dioxide ligand. The reaction is so far the sole catalytic synthesis of spiro-pyrazoline-oxindole derivatives. A wide variety of substrates were explored to obtain good yields (up to 98%) and excellent enantioselectivities (up to 99%). This cycloaddition expands the scope of propargyl anion type 1
An Electrochemical Way to Generate Amphiphiles from Hydrazones for the Synthesis of 1,2,4‐Triazole Scaffold Cyclic Compounds
作者:Wangyu Li、Mingteng Xiong、Xiao Liang、Dungai Wang、Heping Zhu、Yuanjiang Pan
DOI:10.1002/open.202100268
日期:2022.1
Electrochemically forming amphiphiles, hydrazones were chosen as bifunctional reagents analogous to 1,3-dicarbonyl compounds. About 70 1,2,4-triazoles have been prepared in moderate to high yields, testifying to the validity and practicality of this strategy. This approach can also be conducted as a one-pot reaction without intermediate treatments for the construction of 1,2,4-triazoles by using phenylhydrazines
A prototype continuous-flow liquid–liquid extraction system using open-source technology
作者:Matthew O'Brien、Peter Koos、Duncan L. Browne、Steven V. Ley
DOI:10.1039/c2ob25912e
日期:——
A prototype continuous-flow liquidâliquid extraction system is reported. By harnessing several open-source software libraries, a computer control script was written using the Python programming language. Using a âcomputer-visionâ approach, this allowed the computer to monitor the interface level between the organic and aqueous phases using a simple webcam setup and (by dynamically controlling pump flow rate) to keep this interface within defined limits. The system enabled the efficient âinlineâ extraction of excess reagent in hydrazone formations, dithiane formations and epoxidations. The initial results of dispersion measurement are also presented.