Synthesis and spectroscopic studies of isosteviol-calix[4]arene and -calix[6]arene conjugates

Novel calix[4]arene derivatives functionalized with two or four isosteviol units at the upper rim and a new calix[6]arene having six isosteviol moieties at the lower run have been synthesized. The structures of these compounds have been confirmed by NMR and mass spectrometry data. All H-1 and C-13 NMR chemical shifts of isosteviol were fully assigned by extensive NMR spectroscopic methods, and used to clarify the structures and conformations of isosteviol-calixarene, conjuates. (c) 2005 Elsevier Ltd. All rights reserved.