Synthesis of a Dicarba-Analog of Octreotide Keeping the Type II 'β -Turn of the Pharmacophore in Water Solution

The Z isomer of the new constrained analog of the anticancer drug octreotide,where L,L-cystine is replaced by 4,5-dehydro-L,L-diaminosuberic acid,was prepared by solid-phase ring-closing metathesis.NMR study ascertained that this molecule is conformationally very close to the parent octreotide and remains unaffected by the enzymatic pool of the human serum for more than 30 h.