The development of a copper-catalyzed cross-coupling betweenprimary and secondary (pseudo)halides and bicyclopentyl Grignard reagents is reported. Highly strained bicyclopentanes can be cross-coupled with a large panel of primaryalkyl mesylates and secondary alkyl iodides. The catalytic system is simple and cheap, and the reaction is general and chemoselective.
Two new 11C-labelled ligands, N-(3-(4-hydroxyphenyl)propyl)-3-(4-methoxyphenyl)propylamine ([11C]2) and N-(3-(4-hydroxyphenyl)butyl)-3-(4-methoxyphenyl)butylamine ([11C]3) were designed based on bis(phenylalkyl)amines (1) which have been reported as polyamine site antagonists with high-selectivity for NR1A/2B NMDA receptors, and radiolabelling of the corresponding phenol precursors with [11C]methyl iodide was readily accomplished. The in vitro inhibition experiments using rat brain slices showed that [11C]2 and [11C]3 share the binding sites with spermine and/or ifenprodil but not with CP-101,606, a highly potent NR2B-selective NMDA antagonist, and that divalent cations such as Zn2+ produced significant inhibition of both [11C]2 and [11C]3 bindings. Intravenous injection of [11C]3 in mice showed almost homogenous distribution throughout the brain. Attempts to block the tracer uptake of [11C]3 by pre-injection with the unlabelled 3 or spermine in rats were unsuccessful, but a small decrease in the cerebral uptake of [11C]3 by co-treatment with the unlabelled 3 was observed in a monkey PET study. The present findings indicate that none of these 11C-labelled analogues have potential for PET study of binding sites on the N-methly-D-aspartate (NMDA) receptors.
Photocatalyzed site-selective C(sp3)-H sulfonylation of toluene derivatives and cycloalkanes with inorganic sulfinates
作者:Shaonan Zhang、Shi Cao、Yu-Mei Lin、Liyuan Sha、Cheng Lu、Lei Gong
DOI:10.1016/s1872-2067(21)63953-0
日期:2022.3
The development of practical methods for the direct and selective C(sp3)-H functionalization of hydrocarbons is an attractive topic in synthetic chemistry. Although the radical-mediated hydrogen atom transfer (HAT) process has shown considerable potential in such reactions, it still faces fundamental problems associated with reactivity and selectivity. Herein, we report a convenient and economic approach
开发用于烃的直接和选择性C( sp 3 )-H 官能化的实用方法是合成化学中的一个有吸引力的课题。尽管自由基介导的氢原子转移 (HAT) 过程在此类反应中显示出相当大的潜力,但它仍然面临与反应性和选择性相关的基本问题。在此,我们报告了一种方便且经济的位点选择性 C( sp 3 ) -H 磺酰化方法光诱导的 HAT 催化。使用共轭多环醌作为直接 HAT 光催化剂,市售无机亚磺酸盐作为磺酰化源,三氟甲磺酸铜作为廉价氧化剂,多种甲苯衍生物和环烷烃在温和条件下转化为生物和合成有趣的砜产品。机理研究表明,反应顺序涉及直接 HAT 诱导的自由基形成和随后的铜介导的有机金属过程以形成 CS 键。这种方法提供了一个吸引人的机会,可以从丰富的碳氢化合物起始材料和廉价的试剂中提供高附加值的产品。
<b>Efficient and Mild Ytterbium(III)-Catalyzed Tosylation of Alcohols</b>
作者:Ralf Schirrmacher、Slobodan Comagic
DOI:10.1055/s-2004-815998
日期:——
Ytterbium(III) trifluoromethanesulfonate efficiently catalyzes the reaction of primary and secondary alcohols with toluenesulfonic acid anhydride to yield the alkyl tosylates in high yields. The reactions were carried outunder neutral and mild conditions and product purification was easily achieved by means of short column chromatography.