Results 281 to 290 of about 19,238 (306)

Copper-Catalyzed [4+2]-Cycloadditions of Isoxazoles with 2-Alkynylbenzaldehydes To Access Distinct α-Carbonylnaphthalene Derivatives: C(3,4)- versus C(4,5)-Regioselectivity at Isoxazoles

ACS Catalysis, 2019
Cu(II)-catalyzed [4+2]-cycloadditions occur between Cu–benzopyryliums and substituted isoxazoles with the regioselectivity on the C(3,4)-carbons of isoxazoles.
Sovan Sundar Giri, Rai‐Shung Liu
semanticscholar   +1 more source

Cu-Catalyzed Synthesis of Fluoroalkylated Isoxazoles from Commercially Available Amines and Alkynes.

Organic Letters, 2018
A one-pot protocol for the construction of fluoroalkylated isoxazoles directly from commercially available amines and alkynes is described. The reaction is scalable, operationally simple, regioselective, mild, and tolerant of a broad range of functional ...
Xiao-Wei Zhang, Wen-Li Hu, Suo Chen, Xiangguo Hu   +3 more
semanticscholar   +1 more source

Fragmentation mechanisms of isoxazole

Organic Mass Spectrometry, 1981
AbstractFragmentation pathways of isoxazole giving ions [C3H2ON]+, [C2H3N]+˙ and [C2H2N]+ are elucidated by means of metastable ion studies and thermodynamic properties. Rearrangement reactions are demonstrated to occur with H and HCO loss. Elimination of carbon monoxide leads to [C2H3N]+˙ ions whose reacting configuration is the same as for ...
Yannik Hoppilliard, Guy Bouchoux
openaire   +2 more sources

Pyruvic acid-catalyzed one-pot three-component green synthesis of isoxazoles in aqueous medium: a comparable study of conventional heating versus ultra-sonication

Proceedings of the Indian Academy of sciences. Chemical sciences, 2022
S. Deshmukh, A. Nalkar, S. Thopate
semanticscholar   +1 more source

Synthesis of 3-Acyl-isoxazoles and Δ2-Isoxazolines from Methyl Ketones, Alkynes or Alkenes, and tert-Butyl Nitrite via a Csp3-H Radical Functionalization/Cycloaddition Cascade.

Organic Letters, 2019
A novel metal-free tandem Csp3-H bond functionalization of ketones and 1,3-dipolar cycloaddition has been developed. An efficient approach to a variety of oxazole and isoxazoline derivatives is demonstrated using the 1,3-dipolar cycloaddition of alkynes ...
P. Dai, Xin Tan, Qian Luo, Xiang Yu, Shuguang Zhang, Fang Liu, Weihua Zhang   +6 more
semanticscholar   +1 more source

Claisen isoxazole synthesis

2009
Cyclization of β-keto esters with hydroxylamine to provide 3-hydroxy-isoxazoles (3-isoxazolols).
openaire   +2 more sources

Recent advances in transition-metal-catalyzed reactions of alkynes with isoxazoles.

Organic and biomolecular chemistry, 2017
Isoxazoles, as masked 1,3-dicarbonyl equivalents, have proven to be versatile building blocks and pivotal intermediates for the construction of a variety of useful azacycles with molecular complexity.
Long Li, Tong‐De Tan, Ying-Qi Zhang, Xin Liu, L. Ye   +4 more
semanticscholar   +1 more source

Recent Developments in the Synthesis and Reactivity of Isoxazoles: Metal Catalysis and Beyond

, 2015
Isoxazoles are important five-membered aromatic heterocycles in organic chemistry. Recently, many exciting advances in the synthesis and functionalization of isoxazoles have been reported.
Feng Hu, M. Szostak
semanticscholar   +1 more source

Water-Assisted Nitrile Oxide Cycloadditions: Synthesis of Isoxazoles and Stereoselective Syntheses of Isoxazolines and 1,2,4-Oxadiazoles.

Angewandte Chemie, 2016
Conventional methods generate nitrile oxides from oxime halides in organic solvents under basic conditions. However, the present work revealed that water-assisted generation of nitrile oxides proceeds under mild acidic conditions (pH 4-5). Cycloadditions
Chatchai Kesornpun, T. Aree, C. Mahidol, S. Ruchirawat, P. Kittakoop   +4 more
semanticscholar   +1 more source

Benign catalysis with zinc: atom-economical and divergent synthesis of nitrogen heterocycles by formal [3 + 2] annulation of isoxazoles with ynol ethers

, 2018
Herein, we disclose an efficient zinc-catalyzed formal [3 + 2] annulation of isoxazoles with ynol ethers under exceptionally mild reaction conditions, leading to the atom-economical and divergent synthesis of 2-alkoxyl 1H-pyrroles and 3H-pyrroles ...
Xinhai Zhu, Han Yuan, Qing Sun, Bo Zhou, Xiao Han, Zhi-Xin Zhang, Xin Lu, L. Ye   +7 more
semanticscholar   +1 more source