Results 251 to 260 of about 19,561 (308)

Isoxazoles I: Protonation of Isoxazole Derivatives in Aqueous Sulfuric Acid

Journal of Pharmaceutical Sciences, 1973
The protonation of 3-amino-5-methylisoxazole, 5-amino-3,4-dimethylisoxazole, sulfamethoxazole (N-sulfanilamido-5-methyl-3-isoxazole), and sulfisoxazole (N-sulfanilamido-3,4-dimethyl-5-isoxazole) in aqueous sulfuric acid was studied. The pKSH+ and log SH+/S or log SH2+2/SH+ values were determined by UV spectrophotometry.
M. Martinez de Bertorello, Ruben H. Manzo   +1 more
openaire   +3 more sources

Synthesis of Isoxazole- and Oxazole-4-carboxylic Acids Derivatives by Controlled Isoxazole-Azirine-Isoxazole/Oxazole Isomerization

The Journal of Organic Chemistry, 2019
The first synthesis of isoxazole-4-carboxylic acid derivatives by domino isoxazole-isoxazole isomerization is reported. Fe(II)-catalyzed isomerization of 4-acyl-5-methoxy-/5-aminoisoxazoles (dioxane, 105 °C) leads to the formation of isoxazole-4-carboxylic esters and amides in good yields. 4-Formyl-5-methoxyisoxazoles give methyl oxazole-4-carboxylates
Anna V. Serebryannikova, Ekaterina E. Galenko, Mikhail S. Novikov, Alexander F. Khlebnikov   +3 more
openaire   +3 more sources

Oxazolo[4,5-d]isoxazole Derivatives and 3,4-Disubstituted Isoxazoles from Isoxazol-5(4H)-ones

Synthetic Communications, 1993
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
E.M. Beccalli, A. Marchesini, T. Pilati
openaire   +3 more sources

Photochemical and Electrochemical Synthesis of Oxazoles and Isoxazoles: An Update

Advanced Synthesis & Catalysis
This review presents an outline of current advancements in the photochemical and electrochemical synthesis of oxazoles and isoxazoles. Oxazole and isoxazole are important building blocks for a variety of medicinally useful compounds.
Debashis Ghosh, Ancy Sherin, Sumit Ghosh, Sushma A. Kalose, A. Hajra   +4 more
semanticscholar   +1 more source

Isoxazoles—II

Tetrahedron, 1967
Abstract The structure and the spectra of several aminoalkylisoxazoles are presented. Proof is given that aminomethylation (mannich reaction) of isoxazoles can involve different nucleophilic centres.
G. Palamidessi, L. Bernardi, G. Diqual, W. Barbieri, S. Coda, V. Colò   +5 more
openaire   +2 more sources

Synthesis of o-dimethylene isoxazole via isoxazole-fused 3-sulfolene

Tetrahedron Letters, 1992
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Chang, Ruei-Chih, Chou, Ta-Shue
openaire   +3 more sources

Visible-Light-Mediated Three-Component Strategy for the Synthesis of Isoxazolines and Isoxazoles.

Organic Letters
Isoxazolines and isoxazoles commonly serve as core structures of many therapeutic agents and natural products. However, the metal-free and catalysis-free strategy for the synthesis of these privileged motifs at room temperature remains a challenging task.
Yanchuan Li, Yu Zhang, Jinxin Wang, Dingding Xia, Miaomiao Zhuo, Lu Zhu, Dong Li, Shao-Fei Ni, Yanping Zhu, Weidong Zhang   +9 more
semanticscholar   +1 more source

Highly Site Selective Formal [5+2] and [4+2] Annulations of Isoxazoles with Heterosubstituted Alkynes by Platinum Catalysis: Rapid Access to Functionalized 1,3-Oxazepines and 2,5-Dihydropyridines.

Angewandte Chemie, 2017
Platinum-catalyzed formal [5+2] and [4+2] annulations of isoxazoles with heterosubstituted alkynes enabled the atom-economical synthesis of valuable 1,3-oxazepines and 2,5-dihydropyridines, respectively.
W. Shen, Xing Xiao, Qing Sun, Bo Zhou, Xinhai Zhu, Juanzhu Yan, Xin Lu, L. Ye   +7 more
semanticscholar   +1 more source

Trisubstituted isoxazoles from 3,4-disubstituted-(2H)-isoxazol-5-ones

Tetrahedron, 1998
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
E.M. Beccalli, M.L. Gelmi, A. Marchesini
openaire   +3 more sources

Development of Gold-catalyzed [4+1] and [2+2+1]/[4+2] Annulations between Propiolate Derivatives and Isoxazoles.

Angewandte Chemie, 2017
Two new gold-catalyzed annulations of isoxazoles with propiolates have been developed. Most isoxazoles follow an initial O attack on the alkyne to afford a [4+1] annulation product.
Rajkumar Lalji Sahani, Rai‐Shung Liu
semanticscholar   +1 more source