122116-12-5Relevant articles and documents
Efficient Liver Targeting by Polyvalent Display of a Compact Ligand for the Asialoglycoprotein Receptor
Sanhueza, Carlos A.,Baksh, Michael M.,Thuma, Benjamin,Roy, Marc D.,Dutta, Sanjay,Préville, Cathy,Chrunyk, Boris A.,Beaumont, Kevin,Dullea, Robert,Ammirati, Mark,Liu, Shenping,Gebhard, David,Finley, James E.,Salatto, Christopher T.,King-Ahmad, Amanda,Stock, Ingrid,Atkinson, Karen,Reidich, Benjamin,Lin, Wen,Kumar, Rajesh,Tu, Meihua,Menhaji-Klotz, Elnaz,Price, David A.,Liras, Spiros,Finn,Mascitti, Vincent
, p. 3528 - 3536 (2017)
A compact and stable bicyclic bridged ketal was developed as a ligand for the asialoglycoprotein receptor (ASGPR). This compound showed excellent ligand efficiency, and the molecular details of binding were revealed by the first X-ray crystal structures of ligand-bound ASGPR. This analogue was used to make potent di- and trivalent binders of ASGPR. Extensive characterization of the function of these compounds showed rapid ASGPR-dependent cellular uptake in vitro and high levels of liver/plasma selectivity in vivo. Assessment of the biodistribution in rodents of a prototypical Alexa647-labeled trivalent conjugate showed selective hepatocyte targeting with no detectable distribution in nonparenchymal cells. This molecule also exhibited increased ASGPR-directed hepatocellular uptake and prolonged retention compared to a similar GalNAc derived trimer conjugate. Selective release in the liver of a passively permeable small-molecule cargo was achieved by retro-Diels-Alder cleavage of an oxanorbornadiene linkage, presumably upon encountering intracellular thiol. Therefore, the multicomponent construct described here represents a highly efficient delivery vehicle to hepatocytes.
Catalytic Asymmetric Synthesis of Morpholines. Using Mechanistic Insights to Realize the Enantioselective Synthesis of Piperazines
Lau, Ying Yin,Zhai, Huimin,Schafer, Laurel L.
, p. 8696 - 8709 (2016/10/14)
An efficient and practical catalytic approach for the enantioselective synthesis of 3-substituted morpholines through a tandem sequential one-pot reaction employing both hydroamination and asymmetric transfer hydrogenation reactions is described. Starting from ether-containing aminoalkyne substrates, a commercially available bis(amidate)bis(amido)Ti catalyst is utilized to yield a cyclic imine that is subsequently reduced using the Noyori-Ikariya catalyst, RuCl [(S,S)-Ts-DPEN] (η6-p-cymene), to afford chiral 3-substituted morpholines in good yield and enantiomeric excesses of >95%. A wide range of functional groups is tolerated. Substrate scope investigations suggest that hydrogen-bonding interactions between the oxygen in the backbone of the ether-containing substrate and the [(S,S)-Ts-DPEN] ligand of the Ru catalyst are crucial for obtaining high ee's. This insight led to a mechanistic proposal that predicts the observed absolute stereochemistry. Most importantly, this mechanistic insight allowed for the extension of this strategy to include N as an alternative hydrogen bond acceptor that could be incorporated into the substrate. Thus, the catalytic, enantioselective synthesis of 3-substituted piperazines is also demonstrated.
