title: Syntheses and conformations of tetrahomodioxacalix[4]arene tetraamides and tetrathioamides.
abstract: A series of tetrahomodioxacalix[4]arene tetraamides and tetrathioamides with four p-phenyl groups on their upper rim were synthesized. From the (1)H and (13)C NMR and crystal structure, N-butylamido homooxacalix[4]arene (4) was found to be in the 1,3-alternate conformation and has intramolecular hydrogen bonding between N-H and facing oxygen atoms of the carbonyl O=C group. This hydrogen bonding decreased the metal ion complex ability. Transformation of the 1,3-alternate N-butylamido (4) into N-butylthioamido homooxacalix[4]arene (5) using Lawesson's reagent gave a conformational change to the C-1,2-alternate.
authors.affiliation: Department of Chemistry, Sookmyung Women's University, Seoul 140-742, Korea.
authors.forename: Kwanghyun
authors.initials: K
authors.lastname: No
authors.forename: Jeong Hyeon
authors.initials: JH
authors.lastname: Lee
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Yang
authors.forename: Sang Hyeok
authors.initials: SH
authors.lastname: Yu
authors.forename: Moon Hwan
authors.initials: MH
authors.lastname: Cho
authors.forename: Moon Jib
authors.initials: MJ
authors.lastname: Kim
authors.forename: Jong Seung
authors.initials: JS
authors.lastname: Kim