Key analogues of the tetrapeptide subunit of RA-VII and deoxybouvardin Original Research Article

The synthesis and evaluation of the analogues 3 and 4 of deoxybouvardin (1) and RA-VII (2), which contain modifications in the tetrapeptide subunit, are described. Unlike the natural products and similar to our prior disclosure, the agents 3 and 4, which substitute (Gly)4 and (Gly)3 for the d-Ala-Ala-NMe-Tyr(OMe)-Ala tetrapeptide subunit, exist in single rigid conformations in which the central cycloisodityrosine amide adopts its preferred trans stereochemistry and both were found to be biologically inactive.