title: Innovative methodologies for the N-protection of N-alkylimidazole groups: application to the first synthesis of a water-soluble calix[6]arene presenting three ammonium substituents at the large rim and three neutral N-donors at the small rim.
abstract: The first synthesis of a cationic amphiphile calixarene ligand, which bears three neutral imidazole donors on one side of the hydrophobic cone and three quaternary ammonium substituents on the other side, is reported. The synthetic strategy relies on two key steps: (i) the "small rim-directed" selective ipso-nitration at the large rim and (ii) a protection-deprotection sequence of the N-alkylimidazole groups, for which two equally efficient novel methods (coordination to Zn(II) or to a cyanoborane) are presented.
authors.affiliation: Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR CNRS 8601, Université Paris Descartes, 45 rue des Saints-Pères, 75006 Paris, France.
authors.forename: David
authors.initials: D
authors.lastname: Coquière
authors.forename: Jérôme
authors.initials: J
authors.lastname: Marrot
authors.forename: Olivia
authors.initials: O
authors.lastname: Reinaud
mesh_terms: D047250:Calixarenes / Q000138:chemical synthesis*; D008722:Methods; D010636:Phenols; D000644:Quaternary Ammonium Compounds; D012995:Solubility; D014867:Water
chemical_list: D010636:Phenols; D000644:Quaternary Ammonium Compounds; C476540:calix(6)arene; D014867:Water; D047250:Calixarenes