A series of tetrahomodioxacalixarene tetraamides and tetrathioamides with four p-phenyl groups on their upper rim were synthesized. From the 1H and 13C NMR and crystal structure, N-butylamido homooxacalixarene (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 homooxacalixarene (5) using Lawesson's reagent gave a conformational change to the C-1,2-alternate.
ASJC Scopus subject areas
- Organic Chemistry