was investigated. Thus, treatment of 1 with 3 molecular equivalents of DMD afforded a 52% yield of amide 3 as unique isolable organic product. When the reaction was performed with 1 molecular equivalent of DMD the formation of the enol intermediate 15 was evidenced by its capture as the tetrafluoroboric acid salt 16. This salt was unstable and when it was exposed to air gave rise to amide 3 and to
Highly efficient and mild synthesis of nitrones by catalytic oxidation of hydroxylamines with tetra-n-propylammonium perruthenate
作者:Andrea Goti、Francesco De Sarlo、Michela Romani
DOI:10.1016/s0040-4039(00)78275-x
日期:1994.8
Oxidation of N,N-disubstituted hydroxylamines by N-methylmorpholine N-oxide (NMO) and catalytic amounts of tetra-n-propylammonium perruthenate (TPAP) at room temperature occurs very rapidly to give the corresponding nitrones, which can be trapped by dipolarophiles present in the reaction mixture, in excellent yields. A competitive experiment in the presence of a primary alcohol gave a > 50:1 nitrone
Poly(4-vinylpyridine)/methylrhenium trioxide (MTO) compounds IIII and microencapsulated polystyrene/MTO systems IVV are efficient catalysts for the oxidation of secondary hydroxylamines to the corresponding nitrones with H2O2. Complete conversions of substrates and quantitative yields of products are obtained under environmentally friendly experimental conditions and with the use of simple work-up
聚(4-乙烯基吡啶)/三氧化二甲基methyl(MTO)化合物IIII和微囊化的聚苯乙烯/ MTO系统IVV是将仲羟胺氧化为相应的H 2 O 2硝酮的有效催化剂。在环境友好的实验条件下并使用简单的后处理程序即可获得底物的完全转化和定量的产品收率。对称取代的羟胺,以及非对称的3-取代和2-取代的羟基吡咯烷酮,用于生物碱和生物活性同类物合成的硝酮的前体,被认为是底物。该非均相催化剂在反应条件下是稳定的,并且可以被回收和再循环至少五次而没有任何明显的效率损失。
Thermolysis of a Tertiary Alkoxyamine. Recombination and Disproportionation of α-Phenethyl/Diethyl Nitroxyl Radical Pairs
作者:Paul S. Engel、Shaoming Duan、Graciela B. Arhancet
DOI:10.1021/jo961852d
日期:1997.5.1
Alkoxyamine 3 undergoes thermolysis only on heating to over 150 degrees C, Delta H double dagger = 34.3 +/- 1.6 kcal/mol and Delta S double dagger = 0.8 +/- 3.7 eu. The initially formed nitroxyl (6) and alpha-phenethyl radicals (5) mainly disproportionate to styrene plus diethylhydroxylamine (2) but they also recombine to starting material and undergo a new reaction, disproportionation to ethylbenzene plus nitrone(12). The latter reacts with the styrene product to yield oxazolidines 8 and 9. The competition between attack of 6, generated from azo-alpha-phenylethane (1), on 2 versus styrene allowed us to calculate a rate constant at 120 degrees C of 5 x 10(3) M-1 s(-1) for H . transfer from diethylhydroxylamine to 5.
Princ,B.; Exner,O., Collection of Czechoslovak Chemical Communications, 1979, vol. 44, p. 2221 - 2229