57602-02-5Relevant articles and documents
Intraannular functionalization of the 1,3-phenylene-19-crown-6 system via bromine-lithium exchange
Kostas, Ioannis D.,Akkerman, Otto S.,Bickelhaupt, Friedrich,Veldman, Nora,Spek, Anthony L.
, p. 93 - 104 (1999)
In contrast to the behavior of its lower homologue 1,3-phenylene-16-crown-5 (1), the direct lithiation of 1,3-phenylene-19-crown-6 (2) with n-BuLi at the intruannular position-2 was found to be slow and not quantitative. Therefore, (2-bromo-1,3-phenylene)-19-crown-6 (8) was synthesized by the reaction of the dicesium salt of 2-bromo-resorcinol (7) with pentaethylene glycol dibromide. The crystal structure of 8 revealed the existence of three chemically identical residues in the unit cell; in all cases, the bromine atom sticks out of the crown ether ring. The bromine-lithium exchange reaction of 8 with n-BuLi to furnish the desired (2-lithio-1,3-phenylene)-19-crown-6 (4) was quantitative after 2 h at -65°C in THF. Derivatization of 4 with deuterium oxide, dimethyl disulfide, iodine, carbon dioxide, mercuric bromide (1 or 0.5 molar equivalents), and magnesium bromide yielded (2-deuterio-1,3-phenylene)-19-crown-6 (2a), (2methylthio-1,3-phenylene)-19-crown-6 (10), (2-iodo-1,3-phenylene)-19-crown-6 (11), (2-carboxy-1,3-phenylene)-19-crown-6 (12), (2-bromomercurio-1,3-phenylene)-19-crown-6 (13), bis[(1,3-phenylene-19-crown-6)-2-yl]mercury (14), and (2-bromomagnesio-1,3-phenylene)-19-crown-6 (15), respectively. The synthesis of the Grignard reagent 15 was also carried out by the direct reaction of 8 with magnesium; contrary to the corresponding 1,3-xylylene crown ethers, cleavage of the crown ether ring during the formation of 15 was not observed. At room temperature, the solution of crude 4 (prepared from 8) gave rise to ether cleavage and to the formation of (2-n-butyl-1,3-phenylene)-19-crown 6 (16).
Crown-ether-modified cyclic dipeptides as supramolecular chiral catalysts
Bérubé, Christopher,Voyer, Normand
, p. 184 - 195 (2017/10/26)
With the objective to develop supramolecular catalysts for useful chemical transformations, we report here a rapid and efficient solid-phase synthesis of novel cyclic dipeptides (crown-CDPs) with a diversity of L-DOPA derived crown ether substituents and
Bifunctional thiosialosides inhibit influenza virus
Yang, Yang,He, Yun,Li, Xingzhe,Dinh, Hieu,Iyer, Suri S.
supporting information, p. 636 - 643 (2014/01/23)
We have synthesized a panel of bivalent S-sialoside analogues, with modifications at the 4 position, as inhibitors of influenza virus. These first generation compounds show IC50 values ranging from low micromolar to high nanomolar in enzyme inhibition and plaque reduction assays with two intact viruses, Influenza H1N1 (A/California/07/2009) and H3N2 (A/Hongkong/8/68).
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