D-Pyrohomoglutamic acid is a building block.¹It has been used in the synthesis of immunoproteasome low molecular mass polypeptide 2 (LMP2) subunit inhibitors and is a component of substance P peptide analogs.^1,2

1.Johnson, H.W.B., Anderl, J.L., Bradley, E.K., et al.Discovery of highly selective inhibitors of the immunoproteasome low molecular mass polypeptide 2 (LMP2) subunitACS Med. Chem. Lett.8(4)413-417(2017) 2.Hashimoto, T., Uchida, Y., Nishijima, M., et al.Syntheses and biological activities of substance P analogs containing L- and D-homoglutamine and L- and D-pyrohomoglutamic acid at position 5 and 6B. Chem. Soc. Jpn.60(3)1207-1209(1987)