Substituted benzamides. 1. Potential nondopaminergic antagonists of chemotherapy-induced nausea and emesis
作者:Ivo Monkovic、David Willner、Michael A. Adam、Myron Brown、R. R. Crenshaw、Carl E. Fuller、Peter F. Juby、George M. Luke、John A. Matiskella、Thomas A. Montzka
DOI:10.1021/jm00403a011
日期:1988.8
A series of new substitutedbenzamides has been synthesized and evaluated for dopamine antagonist activity and for antagonism of cisplatin-induced emesis in the dog and in the ferret. It was found that modification of the 2-methoxy substituent of metoclopramide was detrimental to dopaminergic D2 antagonism but not necessarily to antagonism of cisplatin-induced emesis. A number of analogues having a
Experimental Evidence for Negative Hyperconjugation as a Component of the Polar Effect: Variation of the Ease of α-Sulfonyl Carbanion Formation with the Orientation of a β-Alkoxy Substituent
作者:James F. King、Rajendra Rathore、Zhenrong Guo、Manqing Li、Nicholas C. Payne
DOI:10.1021/ja001320l
日期:2000.10.1
the incipient carbanion into the # C-O / orbital. This effect is largest with torsion angles of 0 and 180ϒ and at these torsion angles constitutes the major source of stabilization of the incipient carbanion by the ! -alkoxy group. The present observation of a torsion-angle-dependent substituent effect may be combined with the known adherence of the specific rate of R-sulfonyl carbanion formation to
我们报告了强烈依赖几何的取代基效应的证据。R-氢的 HD 交换速率常数 (kexch)OR,在一组 19 ! - 已知的、固定的(或强烈优选的)H-CR-C 的烷氧基砜!- 或已测量扭转角。还测量了缺少烷氧基的相应模型化合物 (kexch) 模型的那些,从而提供比率 kN ) (kexch)OR/(kexch) 模型;如此获得的 kN 值范围超过 4 个数量级。我们表明,当考虑到空间和其他影响时,我们的观察结果与 log kN ) a + b cos 2 " (其中 a ) 1.70 ( 0.17 和 b ) 2.62 ( 0.20) 形式的方程一致。它是进一步表明,观察到的速率常数比与仅由感应效应和场效应组成的取代效应不一致,并且它们与第三种效应的额外存在完全一致,即负超共轭或广义异头效应,特别是初始碳负离子的部分负电荷向#CO/轨道的扭转角依赖性捐赠。这种效应在扭转角为 0 和 180
A Novel Method for the Conversion of Halide Anion to the Positive Halogen by Nitrobenzenesulfonyl Peroxide. Application to Oxyhalogenation of Olefin
Bromide and chloride anions could be readily oxidized into positive halogens by treating with p-nitrobenzenesulfonyl peroxide. The positive halogens, thus formed, reacted with olefins to give epihalonium ions, which were trapped by oxygen nucleophiles inter- or intramolecularly to afford oxyhalogenated compounds.
STEREOCHEMICAL STUDY ON THE REACTION OF COBALOXIME(I) WITH 2-SUBSTITUTED CYCLOHEXYL HALIDES. EVIDENCE FOR AN ELECTRON TRANSFER MECHANISM
作者:Masami Okabe、Masaru Tada
DOI:10.1246/cl.1980.831
日期:1980.7.5
Reaction of cobaloxime (I) , (CoI)−, with 2-hydroxy- (1a and 1b) and 2-alkoxycyclohexyl halides (1c–1h) gave 2-hydroxy- and 2-alkoxycyclohexyl cobaloximes (III) (2 and 3) . Stereochemistry of the organocobaloxime was independent of the configuration of the starting halides. 2-Allyloxycyclohexyl halides (6a and 6b) gave the organocobaloxime having 9-methyl-7-oxabicyclo[4,3,0]nonane moiety. These results
Tribromoisocyanuric Acid: A New Reagent for Regioselective Cobromination of Alkenes
作者:Pierre Esteves、Marcio de Mattos、Leonardo de Almeida
DOI:10.1055/s-2006-941601
日期:2006.6
A simple one-step method for the preparation of tribromoisocyanuric acid in good yield (87%) has been developed. The reaction of tribromoisocyanuric acid with alkenes in presence of nucleophilic solvents (MeOH, i-PrOH, AcOH and a mixture of H2O-acetone, 1:5) led to the corresponding β-bromoethers, β-bromoacetates and bromohydrins, in high regioselectivity and good yields (73-98%).