Preparation of tetraalkylformamidinium salts and related species as precursors to stable carbenes
作者:Roger W. Alder、Michael E. Blake、Simone Bufali、Craig P. Butts、A. Guy Orpen、Jan Schütz、Stuart J. Williams
DOI:10.1039/b104110j
日期:——
Methods are described for the preparation of a range of N,N,N′,N′-tetraalkylformamidinium and N,N-dialkyliminium ions 4–20 as anhydrous salts for use as precursors to diamino- and amino-carbenes. These methods include a novel method involving nucleophilic addition to formamides followed by trapping with electrophiles such as triflic anhydride, various methods of formamide activation, exchange reactions involving orthoesters and the transamination of amidinium salts, and alkylation methods.
作者:Guangpeng Xu、Jinbao Wu、Luyang Li、Yunan Lu、Chao Li
DOI:10.1021/jacs.0c06717
日期:2020.9.9
Daphnezomines A and B are structurally unusual Daphniphyllum alkaloids that contain a unique aza-adamantane core skeleton. Herein, a modular approach to these alkaloids is presented that exploits a diverse array of reaction strategies. Commencing from a chiral pool terpene-(S)-carvone, the azabicyclo[3.3.1]nonane backbone, which occurs widely in Daphniphyllum alkaloids, was easily accessed through
Daphnezomines A 和 B 是结构不寻常的 Daphniphyllum 生物碱,包含独特的氮杂金刚烷核心骨架。在此,提出了一种利用多种反应策略来处理这些生物碱的模块化方法。从手性池萜烯-(S)-香芹酮开始,氮杂双环 [3.3.1] 壬烷主链广泛存在于水蚤生物碱中,可通过 Sharpless 烯丙基胺化和钯催化的氧化环化轻松获得。保护基团启用立体选择性 B-烷基 Suzuki-Miyaura 偶联序列,然后应用基于 Fe 介导的氢原子转移 (HAT) 的自由基环化来构建 C6 和 C8 立体中心。最终的差向异构体锁定策略能够组装高度拥挤的氮杂金刚烷核心,
One-pot synthesis of doxorubicin-loaded multiresponsive nanogels based on hyperbranched polyglycerol
Doxorubicin-loaded nanogels with multiresponsive properties are prepared in a single step using hyperbranched polyglycerol as a biocompatible scaffold.
使用超支化聚甘油作为生物相容性支架,在单个步骤中制备具有多响应性质的多柔比星纳米凝胶。
Biocompatible Thermoresponsive Polymers with Pendent Oligo(ethylene glycol) Chains and Cyclic Ortho Ester Groups
作者:Zeng-Ying Qiao、Fu-Sheng Du、Rui Zhang、De-Hai Liang、Zi-Chen Li
DOI:10.1021/ma101090g
日期:2010.8.10
two types of copolymers, which can be ascribed to the difference in hydrophobicity of the orthoester units. Little hysteresis was observed for the copolymers with more OEGA units while those with more orthoester units showed significant hysteresis probably due to the hydrophobic character of the orthoester. The formation of coacervate droplets above CP reveals that the copolymers underwent a liquid−liquid
具有六元环状原酸酯基的两个丙烯酸酯单体,即丙烯酸2-(1,3-二恶烷-2-基氧基)乙酯(DEA)和2-(5,5-二甲基-1,3-二恶烷-2-)合成了丙烯酸(丙氧基氧基)乙酯(DMDEA)。在原子转移自由基聚合条件下,将这两种单体与低聚(乙二醇)丙烯酸酯(OEGA)共聚,得到两个系列的热敏共聚物,聚(DEA- co- OEGA)和聚(DMDEA- co- OEGA)。所有共聚物均在低温下可溶于水以形成透明溶液,但是,其中一些在低于浊点(CP)时表现出缔合行为,如1所示。1 H NMR,动态光散射(DLS)和荧光法。共聚物的聚集趋势取决于它们的组成以及原酸酯单元的结构。具有相似的组成,聚(DMDEA- co- OEGA)比聚(DEA- co - OEGA)表现出更强的聚集趋势。另外,增加共聚物中原酸酯单元的摩尔含量会促进其在水中的聚集。通过多种方法研究了这些共聚物的热诱导相变,包括浊度法,温度依赖性法11
Synthesis of the dioxabicyclononane unit of tirandamycin
作者:T.Rose Kelly、Nizal S. Chandrakumar、John D. Cutting、R.Richard Goehring、Franz R. Weibel