D. R. Bramlett

Design and synthesis of [2-(8,9-dioxo-2,6-diazabicyclo[5.2.0]non-1(7)-en-2-yl)-ethyl]phosphonic acid (EAA-090), a potent N-methyl-D-aspartate antagonist, via the use of 3-cyclobutene-1,2-dione as an achiral alpha-amino acid bioisostere.

M. Abou-Gharbia, W. Kinney, J. Moyer, 1998, Journal of medicinal chemistry.

Bioisosteric replacement of the alpha-amino carboxylic acid functionality in 2-amino-5-phosphonopentanoic acid yields unique 3,4-diamino-3-cyclobutene-1,2-dione containing NMDA antagonists.

W. Kinney, D. Kowal, R. Tasse, 1992, Journal of medicinal chemistry.