Figure 1.

(A) Structures of core scaffolds for 10 scaffold ranking library samples. (B) Synthetic scheme for library 1954 and individual compounds 2213: the starting N-acylated tetrapeptide, 1, is reduced to the linear polyamine by diborane–THF followed by piperidine treatment to disrupt borane–amine complexes. The next step (b) involved treatment on the resin attached polyamine with oxalyldiimidazole/DMF, to form the bis diketopiperizone (c). This was then again reduced by diborane to yield the desired bispiperazine (d). This synthesis is described in Nefzi et al. 2009.⁹⁰⁰ Throughout this manuscript TPI 1954 library samples and 2213 individual compounds have the core scaffold shown in the second row, far left structure. (C) Structures for individual compounds 2213-18, 2213-23, 2213-24, and 2213-54.