NMR study of the new chiral calix[4]arenes

The H-1 and C-13 NMR spectra of the new chiral calix[4]arene-based dihydrox y-diamides (I) and tetraamides (2) were completely assigned by one- and two -dimensional homo- and heteronuclear experiments (H-1-H-1 COSY, H-1-C-13 HM QC, and HMBC) at 500.13 and 125.77 MHz. H-1 and 13C NMR spectra were measur ed at different temperatures for dihydroxydiamides (1). For the assignment of all signals of carbon atoms, H-1-C-13 HMQC and HMBC were performed. Our results show that the conformation of 1 in solution is very similar to the conformation in solid state (X-ray crystallography). (C) 2001 Elsevier Scie nce B.V. All rights reserved.