5038-17-5Relevant academic research and scientific papers
Synthesis, structural characterization and complexation properties of the first "crowned" dipyrrolylquinoxalines
Kirkovits, Gregory J.,Zimmerman, Rebecca S.,Huggins, Michael T.,Lynch, Vincent M.,Sessler, Jonathan L.
, p. 3768 - 3778 (2007/10/03)
The synthesis of four crown-substituted dipyrrolylquinoxalines 1-4 is reported. The key step in the synthesis is reaction of a 1,2-diaminobenzocrown with 1,2-bis(1H-pyrrol-2-yl)ethanedione (20). A single crystal X-ray diffraction analysis of the 18-crown-6-dipyrrolylquinoxaline 1 revealed that this molecule forms a tetramer centered around a single molecule of water, with no fewer than 10 hydrogen bonds holding the supramolecular structure together. In the case of the 15crown-5-dipyrrolylquinoxaline 2, however, X-ray diffraction analysis revealed that this species exists as a dimeric pair in the solid state, with the NH protons of one pyrrole lying within hydrogen-bonding distance of two oxygen atoms on an adjacent crown ether. A second single crystal structure of 2 was solved; it demonstrated that this system is able to coordinate a potassium cation, thereby forming an intermolecular sandwich complex, at least in the solid state. In [D6]acetone solution receptor 2 and congeners 1, 3 and 4 were also found to complex sodium and potassium cations within the crown diethyl ether binding sites, in a 1:1 manner as judged by 1H NMR spectroscopic analyses. Although systems 1-4 appear to bind fluoride anion as well as cations, the inability to obtain quantitative binding affinities of 1-4 with fluoride anion rendered the evaluation of the systems for cooperative binding impossible. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).
Synthesis of Monoaza Crown Ethers from N,N-Diamines and Oligoethylene Glycol Di(p-toluenesulfonates) or Corresponding Dichlorides
Maeda, Hirokazu,Furuyoshi, Shigeo,Nakatsuji, Yohji,Okahara, Mitsuo
, p. 212 - 218 (2007/10/02)
Monoaza crown ethers were prepared in satisfactory yields by the one-step reaction between diethanolamine or N,N-diamines and oligoethylene glycol di(p-toluenesulfonates) or corresponding dichlorides in t-butyl alcohol/dioxane in the presence of sodium or potassium t-butoxide.The reaction conditions in the preparation of monoaza 15- and 18-crown ethers were studied.Various monoaza crown ethers having substituents were also prepared and their properties were investigated.
