在催化剂1,1-二苯基-存在下,用分子氮稀释的分子氧(O 2 / N 2 = 7/93 v / v,5 MPa)下,伯胺向其相应的肟的氧化转化高效进行。2-吡啶甲基肼基(DPPH)和氧化古铜粉/氧化铝(WO 3 / Al 2 O 3)。该方法对环境无害,因为该反应仅需要分子氧作为末端氧化剂,并产生水作为副产物。各种脂环族胺和脂族胺可以优良的产率转化为它们相应的肟。值得注意的是,伯胺的氧化转化在其他官能团存在下化学选择性地进行。本氧化的关键步骤是将电子从伯胺快速转移至DPPH,然后进行质子转移,以生成α-氨基烷基自由基中间体,该中间体与分子氧和氢的夺取反应生成α-氨基烷基氢过氧化物。过氧化物与WO 3 / Al 2 O 3的后续反应产生肟。仲胺的需氧氧化产生相应的硝酮。环己胺的有氧氧化转化为环己酮肟作为工业生产ε-己内酰胺(尼龙6的原料)的方法很重要。
Tricyclic-isoxazolidine analogues via intramolecular 1,3-dipolar cycloaddition reactions of nitrones
作者:Simon Saubern、James M. Macdonald、John H. Ryan、Ruth C.J. Woodgate、Theola S. Louie、Matthew J. Fuchter、Jonathan M. White、Andrew B. Holmes
DOI:10.1016/j.tet.2010.01.062
日期:2010.4
tetrahydroisoxazolepyranopyridines were prepared by an intramolecular 1,3-dipolar cycloaddition reaction of a nitrone with an alkene. For N-alkylated hexahydroisoxazolequinolines, reduction of the reaction time from two days to 40 min was achieved using microwave heating. The cyclization to form tetrahydroisoxazolepyranopyridines only proceeded when the alkene was substituted with an electron withdrawing group.
<i>N</i>-Vinyl-Nitroimidazole Cycloadditions: Potential Routes to Nucleoside Analogues
作者:Christopher Ramsden、Russell Clayton
DOI:10.1055/s-2005-872083
日期:——
Cycloaddition reactions of 4-nitro- and 5-nitro-1-vinylimidazoles have been investigated. The cycloadducts obtained are potential intermediates for synthesis of purine nucleoside analogues via reduction to the corresponding aminoimidazoles. A byproduct obtained using benzonitrile oxide as 1,3-dipolarophile has been identified as a novel tricyclic isomer 12 of the cycloadduct 11.
Simple and efficient routes for the preparation of isoxazolidinyl nucleosides containing cytosine and 5-methyl-cytosine as new potential anti-HIV drugs
convenient large-scale strategy for the synthesis of some new isoxazolidinyl nucleosides, as potential antiviral drugs, is reported. In particular, a multistep methodology based either on the 1,3-dipolar cycloaddition approach or on a slight modification of the convertible nucleoside concept was exploited in the preparation of 4′-aza-2′,3′-dideoxynucleoside analogues containing cytosine and 5-methyl-cytosine
One-pot sequential deoximation and allylation reactions of aldoximes in aqueous solution
作者:Mei-Huey Lin、Long-Zhi Lin、Tsung-Hsun Chuang、Han-Jun Liu
DOI:10.1016/j.tet.2012.01.074
日期:2012.3
A simple procedure has been developed for conducting tin-mediated deoximation and allylation reactions of aldoximes in water to form homoallylic alcohols. Employing the new conditions, various homoallylic alcohols were produced in good to excellent yields. (C) 2012 Elsevier Ltd. All rights reserved.