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
<i>cis</i>-Selective, Enantiospecific Addition of Donor–Acceptor Cyclopropanes to Activated Alkenes: An Iodination/Michael-Cyclization Cascade
作者:Nils L. Ahlburg、Peter G. Jones、Daniel B. Werz
DOI:10.1021/acs.orglett.0c02210
日期:2020.8.21
biologically interesting scaffolds, including barbiturates and isoxazolones. Mechanistic investigations were undertaken to explain the unusual diastereoselectivity and enantiospecificity; these suggest an iodination/Michael-cyclization cascade.
Knoevenagel type condensation of 4-unsubstituted isoxazolinones with ketones or aldehydes followed by Michael addition of a nucleophile — hydride, cyanide, or phosphite— and exposure of the adduct to sodium nitrite/aqueous acetic acid and ferrous sulfate gives variously functionalised alkynes.
Regioselective Catalytic Asymmetric C-Alkylation of Isoxazolinones by a Base-Free Palladacycle-Catalyzed Direct 1,4-Addition
作者:Tina Hellmuth、Wolfgang Frey、René Peters
DOI:10.1002/anie.201410933
日期:2015.2.23
asymmetric alkylations of isoxazolinones forming all‐C‐substituted quaternary stereocenters. The present studies were driven by the question of how to control the regioselectivity in the competition of different nucleophilic positions. The investigation of a direct 1,4‐addition uncovered that a sterically demanding palladacycle catalyst directs the reactivity in the absence of a base nearly exclusively to
Reaction of 4-arylmethylene-3-phenylisoxazolones and 4-arylmethylene-1,3-diphenylpyrazolones with enamines and nucleophilic heterocycles
作者:David C. Cook、Alexander Lawson
DOI:10.1039/p19740001112
日期:——
4-Arylmethylene-3-phenylisoxazolones (1) and 4-arylmethylene-1,3-diphenylpyrazolones (2) were treated with enamines (8), 3-phenylisoxazol-5(4H)-one (4), 1,3-diphenylpyrazol-5(4H)-one (6), and 2-phenyloxazol-5(4H)-one (3). The enamines were β-alkylated to give 1:1 adducts (9) and (10). The reaction of (1) with (6) and (2) with (4) gave symmetrical benzylidenedi-isoxazolones and -pyrazolones (7). 2-