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Synthesis of new proton‐ionizable crown ether compounds containing substituted lh‐pyridin‐4‐one subcyclic units
Author(s) -
Huszthy Peter,
Kertesz Julia,
Bradshaw Jerald S.,
Izatt Reed M.,
Redd J. Ty
Publication year - 2001
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570380604
Subject(s) - chemistry , moiety , pyridine , methylene , acetic anhydride , crown ether , catalysis , nitration , medicinal chemistry , ring (chemistry) , chloride , nitric acid , organic chemistry , polymer chemistry , ion
Five novel pyridono‐18‐crown‐6 ( 10‐14 ) and two new benzyloxy‐substituted pyridino‐18‐crown‐6 ( 15 and 16 ) ligands have been prepared. By the catalytic hydrogenative removal of the benzyl group from the benzyloxy moiety at position 4 of the pyridine ring of 15 and 16 , pyridono‐18‐crown‐6 ethers 5 and 12 were obtained. These ligands were transformed to their 3,5‐dibromo ( 10 and 13 ) and 3,5‐dinitro derivatives ( 11 and 14 ) by treatment with bromine in methylene chloride and nitric acid in acetic anhydride, respectively. The latter proton‐ionizable crown ethers have p K a values of about 7.5 for 10 and 13 and 4.5 for 11 and 14 . Thus, they are good candidates for complexation and proton‐coupled transport of selected cations.