Dihydroxyglutamic Acid in Plants.

Asymmetric synthesis of 3,4-dihydroxyglutamic acids via enantioselective reduction of cyclic meso-imide

“…The crude product was purified by column chromatography on silica gel (hexane-ethyl acetateZ50:50) to give the title compound 2 (690 mg, 61%) as an oil. 1 …”

“…Coupled with the results obtained in our previous work, 4 the present study provides a facile and versatile protocol for accessing all eight stereoisomers of 3,4-dihydroxyglutamic acids. (1). According to the procedure for the preparation of the corresponding N-benzyl derivative reported by Hiemstra and co-workers, 5 (2).…”

“…3,4-Dihydroxyglutamic acid is a natural glutamic acid derivative, which was isolated from the seeds of Lepidum sativum and the leaves of Rheum rhaponticum about 50 years ago. 1 However, nothing is known concerning the stereochemistry of the three consecutive chiral centers. Recently, two groups reported the stereoselective synthesis of (2S,3S,4S)-and (2S,3S,4R)-3,4-dihydroxyglutamic acid, 2,3 and the former compound was found to be a selective agonist of mGluR1.…”

New Amino Acids of Plants

“…Isolations of larger amounts of these substances are awaited so that their structures may be determined with more certainty. Another type of hydroxyglutamic acid has been isolated from seeds of lettuce, Lepidium sativum, and green parts of rhubarb, Rheum rhaponticum, by Virtanen & Ettala (1957), and has been shown by them to be widely distributed in plants. T h e chemical evidence available indicates that the acid is , I !…”

“…Of the other new amino acids only two, p, y-dihydroxyglutamic acid and pipecolic acid, have been reported to occur widely distributed in plants. Virtanen & Ettala (1957) report that j3, y-dihydroxyglutamic acid is present in twenty flowering plants which they examined. These plants represented a variety of different families, and the acid was stated to occur in leaves, stems, roots and fruits.…”