Selective N-Nitrosation of Amines,<i>N</i>-Alkylamides and<i>N</i>-Alkylureasby N<sub>2</sub>O<sub>4</sub>Supported on Cross-Linked Polyvinylpyrrolidone(PVP-N<sub>2</sub>O<sub>4</sub>)
N2O4 was supported on the cross-linked polyvinylpyrrolidone (PVP) to afford a solid, stable and recyclable nitrosating agent. This reagent shows excellent selectivity for N-nitrosation of dialkyl amines in the presence of diaryl-, arylalkyl-, trialkylamines and also for secondary amides in dichloromethane at room temperature under mild and heterogeneous conditions. Also N-nitroso-N-alkyl amides can be selectively prepared in the presence of primary amides and N-phenylamides under similar reaction conditions. Selective N-nitrosation or dealkylation and N-nitrosation of tertiary amines can also be performed by this reagent.
Thiol Oxidation by 1,2,3-Oxadiazolinium Ions, Presumed Carcinogens
作者:Richard N. Loeppky、Aloka Srinivasan
DOI:10.1021/tx00048a001
日期:1995.9
behavior of these compounds toward typical "cellular nucleophiles". Each of these substances oxidizes benzenethiol to diphenyldisulfide. The reaction in aqueous buffer at pH 7.4 is rapid. Reaction of 1b with benzenethiol gives, in addition to the disulfide, benzene, biphenyl, azobenzene, diphenylsulfide, aniline, and glycolaldehyde. Similar products are obtained from 3. Phenyldiazene is postulated as
Abstract Efficient N‐nitrosation of amines, amides, and ureas, and also S‐nitrosation of thiols were performed with dinitrogentetroxide impregnated on activated charcoal (N2O4/charcoal) in CH2Cl2 at room temperature. High selectivity was observed for N‐nitrosation of dialkyl amines, N‐alkylamides and N‐alkylureas. Dealkylation and N‐nitrosation of trialkylamines were also performed by this reagent
Five hydroxyethyl-2-tetrazenes (1 - 5) and their methyl ethers (6 - 10) have been synthesized and hydrogen bonding in these compounds has been investigated by theoretical and spectroscopic (IR, 1H NMR, 15N NMR) methods. The structure of 1,1,4,4-tetrakis(2-hydroxyethyl)- 2-tetrazene (4) was determined byX-ray diffraction analysis. Several conformationswith intramolecular hydrogen bonds were investigated
合成了五种羟乙基-2-四烯 (1-5) 及其甲基醚 (6-10),并通过理论和光谱 (IR、1H NMR、15N NMR) 方法研究了这些化合物中的氢键。1,1,4,4-四(2-羟乙基)-2-四氮烯(4)的结构通过X-射线衍射分析确定。通过从头算 B3LYP 以及半经验 SCF 计算研究了几种具有分子内氢键的构象。在所有情况下,发现具有 OH- - -N 氢键和偶氮氮原子作为受体的构象异构体(构象 A、B、C)最稳定。除了羟乙基 (3, 4) 外,还带有小的或灵活的 N1-和 N4-取代基 R 的化合物,氢键形成六元环,R 基团在 N1-N2 和 N3-N4 键上占据顺位(构象 A ), 比那些具有七元环和 R 取反位(构象 B)的优先。其他化合物 (1, 2, 5) 中的空间相互作用导致构象 A 不稳定,构象 B 变得更加稳定。一个特殊的例子是化合物 4,它在 2-四氮烯单元上只有羟乙基取代基。在最稳定的构象异构体