Ismail L D, Lorenz P, Stermitz F R
Department of Pharmacognosy, Al-Azhar University, Nasr City, Cairo, Egypt.
J Nat Prod. 1998 Sep;61(9):1174-6. doi: 10.1021/np9801662.
A polar extract of leaves of Justicia ghiesbreghtiana yielded N-(2-hydroxy-4,5-dimethoxyphenyl)-(S)-alpha-malamic acid, 1. Incomplete spectral analysis yielded a hypothetical structure, which was then proven by total synthesis. Coupling of the trifluoroacetate of malic anhydride (trifluoroacetoxysuccinic anhydride) with an arylamine provided the key to regiospecific preparation of the alpha- rather than beta-malamic acids.
