4-Hydroxyglutamic acid

A deacylation reaction has been effected by a reactive lower order cuprate when its reaction paitner has no other pathway available. Thus, Kunieda and Hirobe have found that (-)-3-ketopinyl-2-oxazolone (85) undergoes smooth cleavage of the chiral auxiliary to a ord the heterocycle (86), subsequent elaboration of which leads to either (2S,3/ )-3-hydroxyglutamic acid (87) or (3f ,4 )-4-amino-3-hydroxy-6-methylheptanoic acid (88) as their hydrochloride salts (Scheme 15). ... 

Among the products of hydrolysis of the active material by 10 per cent H2SO4, they were able to identify /3-hydroxyglutamic acid and later y-hydroxyproline. They were of the opinion that their material was a peptide or diketopiperazine which, on hydrolysis, gave /8-hydroxyglutjHni c acid and 7-hydroxyproline. 

Over 30 amino acids have been identified in the hydrolysis product of casein of which glutamic acid, hydroxyglutamic acid, proline, valine, leucine and lysine comprise about 60%. The residues of the aminoacid arginine also appear to be of importance in the cross-linking of casein with formaldehyde. 

L Benoiton, LP Bouthillier. Synthesis of y-hydroxyglutamic acid (diastereomeric mixture). (isolation of amino acid with ion-exchange resin) Can J Chem 33, 1473, 1955. 

Does Hydroxyglutamic Acid Occur in Milk Proteins J. biol. Chem. 

The s)mthesis of e /iro-L-j -hydroxyglutamic acid (844) makes use of the furan heterocycle as a carboxyl equivalent (Scheme 122) [185]. After reduction of 793a to 839 and acetylation (840), the aminal acetate and furan are coupled in the presence of zinc bromide and a catalytic amount of trimethylchlorosilane to give a 67 33 mixture of 841 and 842. In the absence of silane the reaction requires 12 h at room temperature for completion, but with silane present the reaction time is reduced to2hat —15°C. 

Aspartic acid. Glutamic acid. Hydroxyglutamic acid... 

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