Competitive Copper Catalysis in the Condensation of Primary Nitro Compounds with Terminal Alkynes: Synthesis of Isoxazoles
作者:Ausilia Baglieri、Luca Meschisi、Francesco De Sarlo、Fabrizio Machetti
DOI:10.1002/ejoc.201600897
日期:2016.9
are prepared by catalytic condensation of primary nitro compounds with terminalacetylenes by using a copper/base catalytic system. The additional catalytic effect of the copper(II) salts is evidenced by comparing the kinetic profiles. Selectivity dependence on reaction conditions is considered for phenylacetylene in the following competitive processes: oxidative coupling of terminal alkynes to conjugated
异恶唑,主要是 3,5-二取代,是通过使用铜/碱催化系统将伯硝基化合物与末端乙炔催化缩合制备的。通过比较动力学曲线证明了铜 (II) 盐的额外催化作用。在以下竞争过程中,苯乙炔的选择性取决于反应条件:在空气存在下,由 CuII 和碱催化的末端炔烃与共轭二炔的氧化偶联;除了与苯甲酰硝基甲烷缩合生成 3-苯甲酰异恶唑外,还生产呋喃,这是亲偶极试剂与 3,4-二苯甲酰呋喃反应的结果;将缺电子炔烃(例如丙炔酸甲酯)与自身和硝基化合物加成。因此,氧化偶联在与“活性”硝基化合物的反应中可以忽略不计,而对于硝基烷烃,可以观察到两种产物:仅检测到痕量的异恶唑,而没有铜。类似地,在铜存在下,3-苯甲酰基-5-苯基异恶唑比呋喃唑占优势。此外,在单独存在碱的情况下,缺电子炔烃的缩合会产生复杂的反应混合物,但环加合物可以方便地用铜制备。结果表明该催化方法在合成实践中的实用性和普遍性。但环加合物可以方便地用铜制备。
Formation of isoxazole derivatives via nitrile oxide using ammonium cerium nitrate (CAN): a novel one-pot synthesis of 3-acetyl- and 3-benzoylisoxazole derivatives
作者:Ken-ichi Itoh、C.Akira Horiuchi
DOI:10.1016/j.tet.2003.11.088
日期:2004.2
4-diacetyl-1,2,5-oxadiazole 2-oxide) as the dimer of nitrile oxide. Moreover, it was found that yields of isoxazole derivatives were improved using ammonium cerium(III) nitrate tetrahydrate ((NH4)2Ce(NO3)5·4H2O, CAN(III))-formic acid. The reaction mechanisms based on nitration and formation of nitrile oxide mediated by CAN(IV) or CAN(III) from acetone or acetophenone are also proposed.
Method for manufacturing isoxazole derivative or dihydroisoxazole derivative
申请人:Horiuchi Akira C.
公开号:US20060247288A1
公开(公告)日:2006-11-02
There is provided with a method for manufacturing an isoxazole derivative at a high yield and without discharging waste products, and a novel isoxazole derivative. An isoxazole derivative expressed by Formula (8) is produced by reacting a 1-alkyne compound expressed by Formula (7) with iron(III) nitrate in the presence of acetone or acetophenone:
(where R
1
is an alkyl, cycloalkyl, phenyl, or other such group); and
(where R
2
is a methyl or a phenyl).
(several alkenes and alkynes) with ammoniumcerium(IV) nitrate ((NH4)2Ce(NO3)6, CAN(IV)) in acetone under reflux gave 3-acetylisoxazole derivatives. In the case of acetophenone, 3-benzoylisoxazole derivatives were obtained. Moreover, it was found that yields of isoxazole derivatives were improved using ammoniumcerium(III) nitrate tetrahydrate ((NH4)2Ce(NO3)5·4H2O, CAN(III))–formic acid.
by the reaction of alkenes or alkynes with ketones (acetone or acetophenone), as both a reagent and the solvent, by three methods: iron(lll) nitrate under reflux, iron(III) salt-nitrogen dioxide (NO;) at room temperature, and iron(III) nitrate under microwave irradiation (MW).