Dl- Valine

Glycine (hRf 20—25), DL-alanine (hRf 30 — 35), DL-valine hRf 45 — 50) and L-leucine (HRf 55—60) yielded red-violet chromatogram zones on a pale yellow background. The detection limits for these amino acids were 5 ng substance per... 

Oxazolin-5-ones have also proven to be important intermediates in the homologation of carboxylic acids (71AG(E)655). The IV-acyl-DL-valine derivative (402), prepared from the acid chloride of the carboxylic acid and DL-valine by the Schotten-Baumann procedure, was treated with excess acetic anhydride to afford (403). Reaction of (403) with acrylonitrile and triethylamine led to (404) in good yield. Hydrolysis of (404) with dilute alkali or acid gave the y-keto nitrile or y-keto acid (Scheme 89). 

The characteristic absorptions in the i.r. spectra of lactones and amino acids are discussed on pp. 302 and 308 respectively the spectra of (DL)-valine and l-tryptophan are given in Figs 3.36 and 3.37. Further descriptive spectral interpretations for a range of substituted carboxylic acids and their derivatives are given in appropriate preparative sections. 

Schroeder, Iacobellis, and Smith,148 who set out to determine whether or not further evidence might be gleaned for the observation134 that water prevents the deleterious effect of autoclaving on the nutritive value of dried skim-milk. The amino acids used in this study were glycine, L-leucine, and DL-valine glycyl-L-leucine and glycyl-DL-valine were the peptides chosen. 

Glycine Glycinate ion Glycylglycine Glycylglycinate L(+)-Lactic acid L(+)-Lactate ion a-Lactose p-Lactose DL-Leudne L-Leucine L-Leucinate ion L-Malic acid L-Malate ion a-Maltose p-Maltose Methanol L-Methionine Oxaloacetic acid Oxaloacetate ion Palmitic acid Pyruvic acid Pyruvate ion 2-Propanol Succinic acid Succinate ion Sucrose dl-Valine L-Valine L-Valine ion L-Valinate ion Water... 

The working substance of the ITEP-group /9 source was a doubly tritiated crystalline amino acid, DL-valine (Mallikarjunan and Rao, 1969), which is a molecular crystal. As a result of decay, during the time 10 18 sec the valine molecule transforms into the corresponding helium-containing ion (RHe)+. Since the translational symmetry of the crystal is disturbed, no exciton states are produced, and only molecular states of the complex (RHe)+ are excited. Since in molecular crystals the intermolecular interactions are considerably weaker than the intramolecular ones, one can neglect the influence of the valine crystalline surrounding on the /S-decay process and consider only an isolated valine molecule. 

VALIDL. DL-Valine (CjHnNO. Mallikarjunan M, Rao ST (1969) Acta Crystallogr, Sect B 25 296... 

---