N-Oxydihydropyrrole derivatives were synthesized through an intramolecular Claisen condensation reaction. The N-acylation of hindered hydroxylamines played a key role in providing the useful intermediates, which could be converted to a variety of N-oxydihydropyrrole derivatives.
作者:Anaïs Deletraz、Kamal Zéamari、Florent Di Meo、Paul-Louis Fabre、Karine Reybier、Patrick Trouillas、Béatrice Tuccio、Grégory Durand
DOI:10.1039/c9nj03805a
日期:——
paramagnetic resonance spectroscopy for the hydroxymethyl radical (˙CH2OH). The ortho, meta and para mono-substituted-PBN derivatives exhibited similar trapping rates to the parent PBN while surprisingly, nitrones with two MeO-substituents on the ortho-position failed to trap ˙CH2OH. The trapping rates of the parent compounds were ranked as follows: PPN > EPPN > PBN, indicating that the presence of diethoxyphosphoryl
n-butoxy, sec-butoxy, and tert-butoxy moiety, as well as the phenyl by a pyridyl ring. Electronspinresonance spectra and stabilities of the superoxide adducts of the propoxy derivatives were found to be similar to those of the respective EPPN adduct, whereas the electronspinresonance spectra of the superoxide adducts of N-2-(2-ethoxycarbonyl-propyl)-alpha-(4-pyridyl) nitrone and the butoxy derivatives
最近报道了Nt-丁基-α-苯基硝酮衍生物N-2-(2-乙氧基羰基-丙基)-α-苯基硝酮(EPPN)在pH 7.0时形成超氧化物自旋加合物(t(1/2)= 5.25 min ),其比各自的Nt-丁基-α-苯基硝酮或5,5-二甲基吡咯啉N-氧化物加合物(t(1/2)分别约为10和45s)稳定得多。在我们先前对5-(乙氧羰基)-5-甲基-1-吡咯啉N-氧化物衍生物的结构优化研究的基础上,合成了一系列六种不同的EPPN衍生物,并通过1H NMR,13C NMR和IR进行了表征。EPPN的乙氧基被丙氧基,异丙氧基,正丁氧基,仲丁氧基和叔丁氧基部分取代,苯基被吡啶基环取代。发现丙氧基衍生物的超氧化物加合物的电子自旋共振谱和稳定性与各自的EPPN加合物的相似,而N-2-(2-乙氧基羰基-丙基)-的超氧化物加合物的电子自旋共振谱和稳定性。 α-(4-吡啶基)硝酮和丁氧基衍生物伴有分解产物。与5-(乙氧基羰
The influence of hydrophobic solvation on the alkaline hydrolysis of ethyl esters of polar substituted 2-methylpropionic acids in water
作者:G. Schmeer、S. Riembauer、J. Barthel
DOI:10.1007/bf00652543
日期:1990.12
The rate constants of the alkalinehydrolysis of 2-methylpropionic acid ethyl ester, α-hydroxy, α-bromo, α-cyano, and α-nitro-2-methylpropionic acid ethyl ester have been measured in water between 5°C and 45°C with the help of an appropriate conductance bridge developed in our laboratory. The influence of the polar substituents on the rate constant, a powerful probe for discussing two-particle interactions
α-nitroisobutyrate has a four-electron polarographic reduction wave in acid solution, and ethyl hydroxyaminoisobutyrate was confirmed as the reduction product. This may be explained in terms of scheme (2) analogous to scheme (1) proposed for the esters of α-nitrocarboxylic acid with a α-hydrogen. In alkaline solution, the ester has two waves and a similar four-electron reduction product was confirmed at the potential
Anionic Activation in Polymer-Supported Reactions; Nucleophilic Substitution With Anion-Exchange Resins; I. Synthesis of Alkyl Phenyl Ethers, Nitrocarboxylic Esters, and α-Alkyl-β-dicarbonyl Compounds*