N-CBZ-γ-benzyl-L-isoglutamine (5 gm.) was dissolved in 100 ml. of 50% ethanol and hydrogenated for 12 hr. at room temperature and atmospheric pressure in the presence of palladium catalyst (5% Pd on calcium carbonate). The catalyst was filtered off and a trace of calcium ions was removed with oxalic acid. The solution was evaporated to dryness, the residue dissolved in a small amount of hot water, and the solution treated with charcoal. Alcohol was added to the cloud point and L-isoglutamine was recovered from the chilled solution as fine white crystals, m.p. 186-188°, yield 65%.
