proposed synthesis of anti-malarials

It looks like the compounds in this lot of potential anti-malarials are part of a library of 2,5-diketopiperazines. A search on Google Scholar suggests a solid-phase synthesis from dipeptides might be a good strategy.

Solid phase synthesis of a diketopiperazine catalyst containing the unnatural amino acid (S)-norarginine
Jennifer Kowalski and Mark A. Lipton*
Tetrahedron Letters Volume 37, Issue 33 , 12 August 1996, Pages 5839-5840

They use a standard Merrifield polystyrene resin as solid support. I suspect most of the amino acid derivatives will be commercially available.

Next steps: identify cost and source of reagents needed to make the first few compounds.