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Capping Methodology in Cyclodextrin Chemistry: Use of a Symmetrical Diketone Reagent for Regiospecific Installation of Unsymmetrical Imine–Enamine and Imidazole Caps
Author(s) -
Jouffroy Matthieu,
Armspach Dominique,
Louati Alain,
Matt Dominique,
Toupet Loïc
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201303556
Subject(s) - chemistry , imidazole , imine , reagent , cyclodextrin , enamine , medicinal chemistry , diketone , combinatorial chemistry , organic chemistry , polymer chemistry , catalysis
Methylated α‐ and β‐cyclodextrin skeletons were both equipped with an unsymmetrical N ‐(2‐ N ‐alkylaminoacenaphthenyl)alkylimine rigid handle. The capping reaction, which consists of condensing a diaminocyclodextrin with highly symmetrical acenaphthenequinone, was found to be regiospecific when starting from cyclodextrin‐diamines without any symmetry element. All modified cyclooligosaccharides have intra‐annular nitrogen donor atoms. They undergo further cyclization on oxidation, whether chemically with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone or electrochemically, to give highly strained cyclodextrins capped with an unsymmetrical 1,2‐disubstituted 1 H ‐imidazole unit.