Patent ID: 7531506

Claim:
A process for preparing a cycloheptapeptide containing a 5-membered heterocyclic ring as part of the backbone of the cyclic peptide, the cycloheptapeptide being of formula (III): wherein Aaa 2 , Aaa 3 , Aaa 4 , Aaa 5 , and Aaa 6 are independently α-amino acids of L or D configuration, if applies; wherein Aaa 1 is independently an amino azole five member heterocyclic; wherein X is O or S; wherein Y is independently C or CH; Z is CH or CH 2 ; each of the dash lines indicates a permitted second bond, with the proviso that if the second bond exists between Y and the nitrogen atom bearing R g , then R g is absent; R 1 is a benzyl group; R 2 is selected from the group consisting of an alkyl group, an alkenyl group, and an aralkyl group and their substituted derivatives with an hydroxy group, a mercapto group, an amino group, a guanidino group, a halogeno group; R 4 is selected from the group consisting of an alkyl group, an alkenyl group, an aryl group, and aralkyl group and their substituted derivatives with an hydroxy group, a mercapto group, an amino group, a guanidino group, a halogeno group; R 3 and R 5 are each independently selected from the group consisting of H or an alkyl group and its substituted derivatives with an hydroxy group, a mercapto group, an amino group, a guanidino group, a halogeno group; R 6 is 1-methylpropyl; R 7 is methyl; R 8 and R f form a —CH 2 CH 2 CH 2 — group; and each of R a , R b , R c , R d , R e , and R g is H; which process comprises synthezising by solid phase synthesis a linear heptapeptide precursor, the precursor either contains a heterocyclic ring or is able to form a heterocyclic ring; cyclising the linear heptapeptide and if necessary forming the heterocyclic ring.