functionalized allylic gem‐difluorides via catalytic fluorinative Meyer–Schuster‐like rearrangement is disclosed. This transformation proceeded with readily accessible propargylicfluorides, and low‐cost B–F reagents and electrophilic reagents by sulfide catalysis. A series of iodinated, brominated, and trifluoromethylthiolated allylic gem‐difluorides that were difficult to access by other methods were
8-(Methyltosylaminoethynyl)-1-naphthyl (MTAEN) Glycosides: Potent Donors in Glycosides Synthesis
作者:Si-Yu Zhou、Xin-Ping Hu、Hui-Juan Liu、Qing-Ju Zhang、Jin-Xi Liao、Yuan-Hong Tu、Jian-Song Sun
DOI:10.1021/acs.orglett.1c04102
日期:2022.1.21
efficient glycosylation protocol has been established. The MTAEN glycosylation protocol exhibits the merits of shelf-stable donors, mild catalytic promotion conditions, considerably extended substrate scope encompassing both free alcohols, silylated alcohols, nucleobases, primary amides, and C-type nucleophile acceptors, and applicability to various one-pot strategies for highly efficient synthesis of oligosaccharides
作者:Steven J. Mansfield、Craig D. Campbell、Michael W. Jones、Edward A. Anderson
DOI:10.1039/c4cc07876d
日期:——
A flexible, modular ynamide synthesis is reported that uses a wide range of amides and electrophiles, including acyclic carbamates, hindered sulfonamides, and aryl amides.
completely diminished the antibacterialactivity of the known sulfa drug tested, sulfamethoxazole. The sulfa-resistant MRSA strain COL also showed great susceptibility to these desamino-benzenesulfonamides. These results imply a unique mechanism of growth inhibition by these potent desamino-benzenesulfonamides, different from the well-known folate pathway target of sulfonamide antibiotics. Graphical Abstract
摘要合成了由磺酰胺组成的小型聚焦化学文库。这些化合物被设计为缺乏通常在磺酰胺抗生素中发现的对氨基苯部分。使用磁盘扩散和微量稀释试验研究了这些合成化合物对全球主要耐甲氧西林金黄色葡萄球菌(MRSA)菌株USA300(SF8300)和金黄色葡萄球菌(S. aureus)对照菌株ATCC 25923和ATCC 29213的抗菌活性。根据药敏结果,可检测到强力的金黄色葡萄球菌和MRSA USA300生长抑制剂,例如N发现具有最低抑制浓度(MIC)低至5.6μg/ cm 3的-[3,5-双(三氟甲基)苯基] -4-溴苯磺酰胺以及其他有效的磺酰胺。结构与活性的关系表明,这些脱氨基苯磺酰胺需要吸电子取代基才能有效抑制细菌病原体的生长。另外,即使当细菌叶酸合成中间体p时,它们仍具有抑制金黄色葡萄球菌菌株生长的能力。-氨基苯甲酸(PABA)被补充,而PABA补充则完全削弱了已知的磺胺药,磺胺甲恶唑的抗菌活性
Triple Mode of Alkylation with Ethyl Bromodifluoroacetate:
<i>N</i>
, or
<i>O</i>
‐Difluoromethylation,
<i>N</i>
‐Ethylation and
<i>S</i>
‐(ethoxycarbonyl)difluoromethylation
作者:Arghya Polley、Gurupada Bairy、Pritha Das、Ranjan Jana
DOI:10.1002/adsc.201800824
日期:2018.11.5
chemical reactivity of ethylbromodifluoroacetate. Typically, bromodifluoroacetic acid has been used as a difluorocarbene precursor for difluoromethylation of soft nucleophiles. Here we have disclosed nucleophilicity and base dependent divergent chemical reactivity of ethylbromodifluoroacetate. It furnishes lithium hydroxide and cesium carbonate promoteddifluoromethylation of tosyl‐protected aniline
在这份报告中,我们探索了溴二氟乙酸乙酯的化学反应的三重模式。通常,溴二氟乙酸已被用作软亲核试剂的二氟甲基化的二氟卡宾前体。在这里,我们已经公开了溴二氟乙酸乙酯的亲核性和碱依赖性发散化学反应性。它提供了氢氧化锂和碳酸铯,分别促进了甲苯磺酰基保护的苯胺和缺电子的酚的二氟甲基化作用。有趣的是,将碱从氢氧化锂转变为4- N,N-二甲基氨基吡啶(DMAP)甲苯磺酰基保护的苯胺,得到了相应的N-乙基化产物。而高度亲核的苯硫酚提供了相应的S羰基乙氧基二氟甲基化产物在酯水解之前通过快速的S N 2攻击溴原子而形成。这种机制差异是通过几个控制实验确定的。结果表明,二氟甲基化反应是通过串联原位酯水解/脱羧-脱溴化二氟卡宾的形成并随后被软亲核试剂-NHTs或电子缺陷型酚-OH基团捕获而进行的。在DMAP的存在下,酯的水解受到干扰,相反,在乙基部分的亲核攻击提供了N-乙基化产物。因此,除了开发实用的碱促氮素胺和电