The nature of the bridging nitrido ligand. Synthesis and reactivity of heterobimetallic nitrido-bridged compounds
作者:Carolyn M. Jones、Nancy M. Doherty
DOI:10.1016/0277-5387(94)00355-i
日期:1995.1
)(OSiMe 3 ) 3 and a group VIII metal chloride or hydride product. Comparison of the reactivity and spectroscopic data among the nitrido-bridged compounds and with related iridium(I) and rhodium(I) complexes suggests that the nitrido-bridged compounds are best viewed as adducts in which anionic [(R 3 SiO) 3 VN:] − acts as a simple two-electron donor to the 14-electron cationic [M(L)(PPh) 2 ] + fragment
Trialkylsilylaminyl radicals. Part 1. Electron spin resonance studies of the photolysis of silylated hydrazines, hydroxylamines, triazenes, and tetrazenes
作者:John C. Brand、Brian P. Roberts、Jeremy N. Winter
DOI:10.1039/p29830000261
日期:——
C–H groups, adds to ethylene, t-butyl isocyanide, and trialkyl phosphites; the bis(triethylsilyl)-aminyl radical behaves similarly. Differences between (R3Si)2N˙ and (R3C)2N˙ are attributed to the σ-donor–π-acceptor substituent effect of the trialkylsilyl ligand. The reactivity of (R3Si)2N˙ is generally similar to that of ButO˙, although the steric congestion at the radical centre in the former results
已经通过电离能谱研究了液相uv光解许多三烷基甲硅烷基化的肼,羟胺,三氮烯和四烯所产生的自由基。双(三甲基硅烷基)-aminyl自由基(ME 3 Si)的2由(ME的光解产生的N,3 Si)的2 NN(森达3)2,(ME 3 Si)的2 NOSiMe 3,或(ME 3 Si)的2 NN NN(SiMe 3)2的反应性比二烷基氨基基团强得多。它从脂肪族CH基团中提取氢,并添加到乙烯,叔丁基异氰酸酯和亚磷酸三烷基酯中;双(三乙基甲硅烷基)-氨基自由基的行为类似。之间的差异(R 3 Si)的2 n和(R 3 C)2 N被归因于三烷基甲硅烷配体的σ供体-π-受体取代基的效果。(R 3 Si)2 N 3的反应性通常与Bu t O 3相似,尽管前者在自由基中心的空间拥塞导致偏向受阻较少部位的进攻。例如,虽然卜吨ö和H 2N 3都与异丁烷反应,主要得到Bu t 3,(Me 3 Si)2 N 4在室温以下主要得到Bu
Preparation of Nucleosides Derived from 2-Nitroimidazole and <scp>d</scp>-Arabinose, <scp>d</scp>-Ribose, and <scp>d</scp>-Galactose by the Vorbrüggen Method and Their Conversion to Potential Precursors for Tracers To Image Hypoxia
作者:Anna Schweifer、Friedrich Hammerschmidt
DOI:10.1021/jo200727k
日期:2011.10.21
acetylated at the other ones in a one-pot reaction, mixtures of anomeric 1-O-acetyl derivatives were obtained. These were coupled by the Vorbrüggen method and then deblocked at C-5 and tosylated to give precursors for tracers to image hypoxia in four steps without using Hg(CN)2 necessary for other methods. The Vorbrüggen conditions enable a shorter route to azomycin nucleoside analogues than the previous coupling
converted to a potential precursor for a fluorine-18 labeled hypoxia tumor marker. Two nonradioactive standards, the 6′-deoxy-6′-fluorogalactosyl and the 4′-deoxy-4′-fluoroglucosyl analogue were also prepared. These 2-nitroimidazole nucleosides were prepared by a modified Vorbrüggen coupling. Acetyl-protected 1-(β-d-galactopyranosyl)-2-nitroimidazole was converted to a potential precursor for a fluorine-18