SN2 Substitution Reactions at the Amide Nitrogen in the Anomeric Mutagens, N-Acyloxy-N-alkoxyamides
作者:Katie L. Cavanagh、Stephen A. Glover、Helen L. Price、Rhiannon R. Schumacher
DOI:10.1071/ch09166
日期:——
amide character and resemble α-haloketones in reactivity. They are susceptible to SN2reactions at nitrogen, a process that is responsible for their mutagenic behaviour. Kinetic studies have been carried out with the nucleophile N-methylaniline that show that, like SN2reactions at carbon centres, the rate constant for SN2 displacement of carboxylate is lowered by branching β to the nitrogen centre, or
N-酰氧基-N-烷氧基酰胺1a是不寻常的异头异构酰胺,其由于双氧基取代而在氮上呈锥体状。通过这种构型,它们失去了大部分酰胺特性,并且在反应性上类似于α-卤代酮。它们在氮气下易受S N 2反应的影响,这是导致其诱变行为的原因。动力学研究已经进行了与亲核试剂Ñ甲基苯胺,显示的是,最喜欢S ñ在碳中心,速率常数为S 2个的反应Ñ通过将β分支到氮中心或烷氧基侧链上的大体积基团,可降低2羧酸盐的置换。然而,羧酸酯离去基团上的支链或大体积基团不影响取代率,其主要由离去的羧酸酯基团的p K A控制。这些结果与氨与N-乙酰氧基-N-甲氧基乙酰胺的模型反应的计算性质相符,但与空间效应对其致突变性的作用相反。
Practical Preparation of Esters and Thioacetates from Alkyl Halides and Carboxylates or Thioacetate Catalyzed by PEG400 without Solvent
Abstract Carboxylic esters and thioacetates were conveniently prepared in good to excellent yields under mild conditions by the reaction of alkyl halides with sodium carboxylates or sodium thioacetate catalyzed by PEG400 in the absence of solvents.
Palladium-Catalyzed Cross-Coupling Reactions of Carboxylic Anhydrides with Organozinc Reagents
作者:Donghui Wang、Zhaoguo Zhang
DOI:10.1021/ol035801w
日期:2003.11.1
[reaction: see text] Negishi-type cross-coupling reaction was effected by employing organozincs and anhydrides or mixedanhydrides that formed in situ fromsodiumsalts of the corresponding acids and ethyl chloroformate under the catalysis of palladium(0). A general method for preparing symmetrical/unsymmetrical ketones was developed.
The syntheses of 32 complexes of the type (η-C5H5)2Ti(OOCC6H4X)2 are reported together with their mass, 1H NMR, 13C NMR, mid- and far-IR spectra. The data are consistent with a model in which the TiOOC bond strength (weaker than that of TiCp and TiHal) is stabilized by electron-withdrawing substituents X on the phenyl rings. The electronic influence of X also extends into the cyclopentadienyl rings
的类型的32种复合物的合成(η-C 5 H ^ 5)2的Ti(OOCC 6 H ^ 4 X)2与它们的质量,一起报告1 H NMR,13 C NMR,中期和远红外光谱。该数据与通过苯环上的吸电子取代基X稳定了TiOOC键强度(比TiCp和TiHal的强度弱)的模型一致。X的电子影响也延伸到环戊二烯基环中。
Synthesis, characterization and thermal behaviour of solid 4-methoxybenzoates of heavier trivalent lanthanides
作者:Emanuel C. Rodrigues、Adriano B. Siqueira、Elias Y. Ionashiro、Gilbert Bannach、Massao Ionashiro
DOI:10.1016/j.tca.2006.09.014
日期:2006.12
thermogravimetry and differential thermal analysis (TG–DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy and complexometry were used to characterize and to study the thermalbehaviour of these compounds. The results led to information about the composition, dehydration, phase transition, coordination mode, structure, thermalbehaviour and thermal decomposition of the