SYNTHESIS AND HIGH-FIELD NMR-STUDY OF A NEW CYCLODIPEPTIDE-BETA-CYCLODEXTRIN DERIVATIVE

The synthesis and high held NMR study of a new cyclopeptide functional ized-beta-cyclodextrin beta-CDen-c-(Glu-Glu) (3) in aqueous solution a re reported. This compound has been synthesized by condensation of the ethylendiamine-beta-cyclodextrin derivative beta-CDen (1) with the cy clo-(glutamyl-glutamyl) [c-(Glu-Glu)] (2). The NMR analysis has been c arried out on 500; 600 and 750 MHz instruments and has been largely ba sed on advanced two-dimensional NMR experiments, i.e. DQF-COSY, TOCSY, HMQC and HMBC. The selective excitation technique (1D TOCSY) has also been applied. The study has led to a complete H-1 and C-13 NMR assign ment of the pendant moiety and the modified glucopyranose unit (A), an d a detailed assignment of the unmodified glucopyranose units (B-G). D ata about the preferred conformation of 3 are also acquired by means o f ROESY experiments.