title: An extended cavitand with an introverted carboxylic acid.
abstract: The condensation of a Kemp's triacid derivative with a diamino resorcinarene yielded a cavitand with the deepest cavity prepared to date featuring an inwardly-directed carboxylic acid. The extended 6,7-diaminoquinoxaline wall bearing the acid allowed accommodation of large amines, such as 1-adamantanemethylamine, as well as smaller amines such as triethylamine. Adamantyl and cyclohexyl isocyanides are also bound in the deep cavitand in a way that positions the isonitrile function near the carboxylic acid group. Reaction occurs inside the cavity at ambient temperature to form the respective N-acylformamides. Low concentrations of the transient O-acyl isoamide intermediate were detected by (1)H NMR and IR spectroscopy.
authors.affiliation: The Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, California, 92037, USA.
authors.forename: Shengxiong
authors.initials: S
authors.lastname: Xiao
authors.forename: Dariush
authors.initials: D
authors.lastname: Ajami
authors.forename: Julius
authors.initials: J
authors.lastname: Rebek
mesh_terms: D000588:Amines / Q000737:chemistry; D047250:Calixarenes / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry*; D004988:Ethers, Cyclic / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000737:chemistry; D012118:Resorcinols / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013696:Temperature
chemical_list: D000588:Amines; D002264:Carboxylic Acids; D004988:Ethers, Cyclic; D012118:Resorcinols; C442939:cavitand; C466160:resorcinarene; D047250:Calixarenes; D010649:Phenylalanine