Expeditious green synthesis of 3,4-disubstituted isoxazole-5(4H)-ones catalyzed by nano-MgO
作者:Hamzeh Kiyani、Fatemeh Ghorbani
DOI:10.1007/s11164-016-2498-7
日期:2016.9
three-component reaction of hydroxylaminehydrochloride with aryl aldehydes (or heteroaryl aldehydes) and β-oxoesters to synthesize some biologically active isoxazole-5(4H)-one-based heterocycles. The reactions were completed using 3 mol% catalyst loading in aqueous medium at room temperature. Nano-MgO was synthesized by precipitation and hydrothermal treatment of aqueous salt solution. The structure of the
Facile and expedient synthesis of α,β-unsaturated isoxazol-5(4H)-ones under mild conditions
作者:Fatemeh Ghorbani、Hamzeh Kiyani、Seied Ali Pourmousavi
DOI:10.1007/s11164-019-03999-7
日期:2020.1
three-component cyclocondensation of aryl/heteroaryl aldehydes, hydroxylamine hydrochloride, and β -ketoesters toward the synthesis of α , β -unsaturated isoxazol-5(4 H )-ones under green conditions. The reaction yielded the corresponding heterocycles at room temperature in relatively shorter reaction times. It merits mentioning that the mild conditions allow the synthesis of several α , β -unsaturated isoxazol-5(4
摘要 发现芳基/杂芳基醛,羟胺盐酸盐和 β- 酮酸酯的三组分环缩合反应可催化 纳米SiO 2 -H 2 SO 4合成 α , β- 不饱和异恶唑-5(4 H )-在绿色条件下。该反应在室温下以相对较短的反应时间产生相应的杂环。值得一提的是,温和的条件允许合成几种 α , β- 不饱和异恶唑-5(4 H )-使用此方法的人。在这项研究中,还合成并表征了一些新的异恶唑酮衍生物。它高效,清洁,简单,安全且生态友好。这种简单的方法具有成本效益,并且不需要制备反应物。在不使用能量源(例如热,超声波和微波辐射)的情况下进行三组分环化。 图形摘要
Ag/SiO2 as a recyclable catalyst for the facile green synthesis of 3-methyl-4-(phenyl)methylene-isoxazole-5(4H)-ones
作者:Surya Narayana Maddila、Suresh Maddila、Werner E. van Zyl、Sreekantha B. Jonnalagadda
DOI:10.1007/s11164-015-2167-2
日期:2016.3
An efficient and facile green method for synthesis of 3-methyl-4-(phenyl)methylene-isoxazole-5(4H)-one (4a-m) via room temperature reaction of hydroxylamine, ethylacetoacetate and substituted aromatic aldehydes is designed, using Ag/SiO2 as catalyst with water as solvent. This protocol offers several advantages, such as it being a benign, energy conserving and eco-friendly reaction with products obtained in excellent yields (88–93 %). The reaction requires relatively short reaction times (< 1 h), a simple workup procedure with good atom efficiency and easily recoverable catalyst. The heterogeneous catalyst, Ag/SiO2, was fully characterized and is reusable without loss of activity for up to seven cycles with marginal activity loss.
On the Necessity of One-Pot Tautomer Trapping in Asymmetric Michael Reactions of Arylideneisoxazol-5-ones
作者:Antonio Macchia、Valentina Dafnae Cuomo、Antonia Di Mola、Giovanni Pierri、Consiglia Tedesco、Laura Palombi、Antonio Massa
DOI:10.1002/ejoc.202000286
日期:2020.4.23
The issue of the obtaining of complex tautomeric mixtures of 4‐mono‐substituted isoxazol‐5‐ones has been overcome by the use of entrapping reactants in a one‐pot protocols of Michael reactions with arylideneisoxazol‐5‐ones. Asymmetric three components Michael/electrophilic tautomer‐entrapping and four‐component Knoevenagel/Michael/electrophilic‐tautomer‐entrapping methodologies have been developed
Studies on heterocyclic chemistry. Part XII. Tautomerism of α-(5-oxo-Δ<sup>3</sup>-isoxazolin-4-yl)benzylphosphonates
作者:Tarozaemon Nishiwaki、Koichi Kondo
DOI:10.1039/p19720000090
日期:——
α-(5-Oxo-Δ3-isoxazolin-4-yl)benzylphosphonates (2) mostly exist in the NH form in the solid state, and in the OH form in non-polar solvents, owing to chelation with the phosphonyl group. The tautomeric equilibrium in solution is influenced by the nature of the 3-substituent in the isoxazole ring; the 3-methyl compounds exist partially in the NH form. A modified synthesis of these compounds is described