已经实现了高效的Cu(II)催化的马来酰亚胺自由基加成。鉴定出的铜催化剂可通过裂解酮肟中的O-H键,然后将自由基添加到N-取代的马来酰亚胺中,从而形成肟自由基(N-O )。通过EPR光谱和可变温度1 H NMR检测并确认了肟自由基(NO )。简单的一锅反应可轻松制备中度到良好收率的各种肟醚加合物产物。
selectivity profile towards the hH2R, e.g. 157 being at least 3800-fold selective within the histamine receptor family. The structural similarities of our monomeric ligands to pramipexole (6), a dopamine receptoragonist, suggested an investigation of the binding behavior at those receptors. The target compounds were (partial) agonists with moderate affinity at the hD2longR and agonists with high affinity
即使在今天,组胺H 2受体(H 2 R)在中枢神经系统(CNS)中的作用仍然广为人知。在先前的研究中,许多二聚体,高亲和力和亚型选择性的氨基甲酰基胍型配体,例如UR-NK22(5,p K i = 8.07)被报道为H 2 R激动剂。但是,它们在中枢神经系统中研究H 2 R的适用性因其分子和药代动力学特性(例如高分子量)而受到限制,因此其生物利用度有限。满足对更多类似毒品的H 2的需求R激动剂具有高亲和力,我们合成了一系列含有各种间隔基和侧链部分的单体(硫代)氨基甲酰基胍型配体。这种结构上的简化导致了有效的(部分)激动剂(豚鼠右心房,[ 35 S]GTPγS和β-arrestin2募集试验),其人类(h)H 2 R亲和力在一位纳摩尔范围内(p K i(139,UR-KAT523):8.35; p K i(157,UR-MB-69):8.69)。本文介绍的大多数化合物对hH 2 R表现出出色
Cyanuric Chloride as a Mild and Active Beckmann Rearrangement Catalyst
organocatalytic Beckmannrearrangement of ketoximes into amides has been realized by the catalytic use of cyanuric chloride. Furthermore, acids such as HCl and ZnCl2 are effective as cocatalysts with cyanuric chloride. For example, azacyclotridecan-2-one, which is synthetically useful as a starting material for nylon-12, was prepared in quantitative yield by the Beckmannrearrangement of cyclododecanone
Photocatalyzed Triplet Sensitization of Oximes Using Visible Light Provides a Route to Nonclassical Beckmann Rearrangement Products
作者:Xiao Zhang、Tomislav Rovis
DOI:10.1021/jacs.1c10148
日期:2021.12.22
photoisomerization of oximes via visible-light-mediated energy transfer (EnT) catalysis. Facile access to (Z)-oximes provides opportunities to achieve regio- and chemoselectivity complementary to those of widely used transformations employing oxime starting materials. We show an enhanced one-pot protocol for photocatalyzed oxime isomerization and subsequent Beckmannrearrangement that enables novel reactivity with
Copper-Catalyzed Unstrained C–C Single Bond Cleavage of Acyclic Oxime Acetates Using Air: An Internal Oxidant-Triggered Strategy toward Nitriles and Ketones
A copper-catalyzed aerobic oxidative C–C single bondcleavage of acyclic unstrained oxime acetates is reported, providing various aryl nitriles and ketones in good yields. Mechanistic studies indicate a radical procedure is involved in this transformation, and the oxygen atom in the ketone products is originated from O2 in the air. Oxime acetates as an internal oxidant have been proved to be an initiator