The direct aldol reaction using bifunctional catalysts
作者:Michael A. Calter、Robert K. Orr
DOI:10.1016/s0040-4039(03)01332-7
日期:2003.7
In this paper, we describe an approach to the directaldolreaction using a bifunctional catalyst containing Lewis acidic and basic functional groups. To achieve this novel means of catalysis we have developed new tertiary amine–zinc catalysts, which perform the aldolreaction between acetone and p-nitrobenzaldehyde.
Lactenediynes are compounds characterized by the fusion of a beta-lactam with a cyclodeca-3-ene-1,5-diyne. In this work the most promising members of this family have been activated by attaching a carbalkoxy or a carbamoyl group to the azetidinone nitrogen, and conjugated to various DNA-complexing moieties, either acting by intercalation or through groove binding. These conjugated artificial enediynes have been demonstrated to possess in vitro ability to produce single and double strand cleavage of plasmid DNA. As potency and capacity to induce double cut, they rank among the best simple enediyne analogues ever prepared. A thorough investigation was carried out in order to develop the best suited linkers for assembling these conjugates. (C) 2008 Elsevier Ltd. All rights reserved.
<i>N</i>-Acetylgalactosamino Dendrons as Clearing Agents to Enhance Liver Targeting of Model Antibody-Fusion Protein
作者:Barney Yoo、Sarah M. Cheal、Geralda Torchon、Anna Dilhas、Guangbin Yang、Jun Pu、Blesida Punzalan、Steven M. Larson、Ouathek Ouerfelli
DOI:10.1021/bc400333m
日期:2013.12.18
Dendrimer clearing agents represent a unique class of compounds for use in multistep targeting (MST) in radioimmunotherapy and imaging. These compounds were developed to facilitate the removal of excess tumor-targeting monoclonal antibody (mAb) prior to administration of the radionuclide to minimize exposure of normal tissue to radiation. Clearing agents are designed to capture the circulating mAb, and target it to the liver for metabolism. Glycodendrons are ideally suited for MST applications as these highly branched compounds are chemically well-defined, thus advantageous over heterogeneous macromolecules. Previous studies have described glycodendron 3 as a clearing agent for use in three-step MST protocols, and early in vivo assessment of 3 showed promise. However, synthetic challenges have hampered its availability for further development. In this report we describe a new sequence of chemical steps which enables the straightforward synthesis and analytical characterization of this class of dendrons. With accessibility and analytical identification solved, we sought to evaluate both lower and higher generation dendrons for hepatocyte targeting as well as clearance of a model protein. We prepared a series of clearing agents where a single biotin is connected to glycodendrons displaying four, eight, sixteen or thirty-two alpha-thio-N-acetylgalactosamine (alpha-SGalNAc) units, resulting in compounds with molecular weights ranging from 2 to 17 kDa, respectively. These compounds were fully characterized by LCMS and NMR. We then evaluated the capacity of these agents to clear a model I-131-labeled single chain variable fragment antibody-streptavidin (I-131-scFv-SAv) fusion protein from blood and tissue in mice, and compared their clearing efficiencies to that of a 500 kDa dextran-biotin conjugate. Glycodendrons and dextran-biotin exhibited enhanced blood clearance of the scFv-SAv construct. Biodistribution analysis showed liver targeting/uptake of the scFv-SAv construct to be 2-fold higher for compounds 1 to 4, as well as for the 500 kDa dextran, over saline. Additionally, the data suggest the glycodendrons clear through the liver, whereas the dextran through reticuloendothelial system (RES) metabolism.
Paruszewski, Ryszard; Dolinska, Ewa; Gumulka, Stanislaw, Polish Journal of Chemistry, 1985, vol. 59, # 1, p. 89 - 92