THERMAL-ISOMERIZATION OF N-OXALYL DERIVATIVES OF DIAMINO ACIDS

The neurotoxic constituent of the legume Lathyrus sativus, beta-N-oxal yl-alpha,beta-diaminopropionic acid, was thermally isomerized to an eq uilibrium mixture (60/40) containing the non-toxic alpha-N-oxalyl-alph a,beta-diaminopropionic acid. The same equilibrium mixture was establi shed by starting with the alpha-isomer but required longer time. alpha - and gamma-N-Oxalyl-alpha,gamma-diaminobutyric acids also underwent t hermally induced isomerization with alpha-gamma, or gamma-alpha migrat ion of the oxalyl group. Delta-N-Oxalylomithine and epsilon-N-oxalylly sine did not isomerize under these conditions. The observation that th e higher homologues do not undergo isomerization suggests the intramol ecular nature of the reaction.