Dl-THREONINE

Reaction of Bisglycinatocopper(II). Bisglycinatocopper(II) [13479-54-4] condenses with ahphatic aldehydes. Removal of copper from the condensate results in P-hydroxy-a-amino acid. This is a classical synthetic method of DL-threonine, but the formation of i //o-isomer is unavoidable. 

Vercellotti and associates121,126 were the first to apply the Helferich -Wedemeyer procedure127 (which uses mercury dicyanide as the acid acceptor) for the preparation of a glycosylamino acid, namely, 3-0-(2-acetamido-3,4,6-tri-0-acetyl-2-deoxy-/ -D-glucopyranosyl)-N-(2,4-di-nitrophenyl)-L-serine and -DL-threonine methyl ester derivatives (162). 

Preferential crystallisation is one option for optical resolution on a manufacmr-ing scale. Online polarimetry and refractometry have been used to d3mamically optimise the process for resolution of DL-threonine in aqueous solution by variation of process parameters such as degree of supersaturation, seed quantity, initial enantiomeric excess and scale [148]. The method is claimed to be suitable for control of quasi-continuous processes. 

In the optical resolution of DL-threonine mixtures by batch preferential crystallization, changes of solution concentration and crystal purity were measured. The mechanism of nucleation of the un-seeded enantiomer was discussed to explain the purity decrease of the resolved crystals. From the observation of crystallization behavior of the seed crystals of L-threonine, it was concluded that the existence of the D-enantiomer on the surface of the seed caused the sudden nucleation when they grew to attain sufficient amounts. 

DL-threonine and L-threonine crystals were supplied from Ajinomoto Co. Inc. and were used without further purification. Excess amounts of DL-threonine crystalline particles were dissolved in water kept at 55, 57, 58 or 60 C. After decantation and filtration each saturated solution was placed in the crystallizer maintained at 50 C. The difference between the saturation temperature and the crystallization temperature was defined as the initial supersaturation in terms of supercooling of the solution and was the driving force for the crystallization. 

Several nickel(II) complexes have been reported with Schiff bases derived from the condensation of salicylaldehyde and various amino acids. The structures of the complexes were investigated by means of electronic and NMR spectra as well as X-ray crystallography.2336-2341 Recently the X-ray structure of complex (321), prepared by the reaction of pyridoxal-HCl, o-phospho-DL-threonine and N NOsVfiHaO at pH 5, has been reported.2341... 

Azole approach. Sulfomycimine (523 R = H), from acid hydrolysis of the antibiotic sulfomycine, can be synthesized by the condensation of thiazole-4-carboxylic acid with DL-threonine ethyl ester, followed by cyclization and ester hydrolysis (77H(8)46l). 

A mixture of DL-threonine and DL-allothreonine was prepared by the hydrogenation of ethyl diazoacetoacetate over paltinum oxide in 70% ethanol containing sulfuric acid (eq. 9.90). 2,4-Dimethylpyrrole-3,5-dicarboxylic acid diethyl ester was also obtained as a byproduct. 

Schraml et al.(137) found that the Si resonances of a series of silyl ester, alkoxy-silyl, and amino-silyl derivatives appear in different regions of the spectrum. On the basis of this information they suggested that Si NMR can be used for the structure elucidation of silylated hydroxy- or aminoacids. The silicon chemical shifts for DL-serine [55] and DL-threonine [56 ] are shown in ppm. The variation in the shielding for the alkoxy-silyl group demonstrates the previously noted sensitivity of Si NMR to the nature of R in Mc3SiOR. (140)... 

Thioureas Benzylisothiocyanate. dl-Threonine Benzylamine. Mercuric acetate. 

Daniel, V. A., Leela, R., Doraiswamy, T. R., Rajalakshmi, D., Venkat Rao, S., Swaminathan, M., and Parpia, H. A. B. (1966). The effect of supplementing a poor kaffir com (Sorghum vulgare) diet with L-lysine and DL-threonine on the digestibility coefficient, biological value and net utilization of proteins and retention of nitrogen in children. /. Nutr. Diet. 3,10-14. 

USE In the manuf of copolymers with vinyl acetate used in lacquers and paper sizing in the manuf of softening agents fnr synthetic rubber. In medicinal chemistry, e.g., in the manuf of DL -threonine, vitamin A. 

DL-Threonine (2), D-Senne (8) DL-Valine (2), D-Serine (8) DL-Norvahne (2), D-Serine(8) 3-Fluoro-D-Alamne (8)... 

Ethyl 3-methylcrotonate thus gives ethyl 2-bromo-3-methoxy-3-methylbutyrate,305 ethyl crotonate gives ethyl 2-bromo-3-methoxybutyrate,28 8.306 and ethyl acrylate gives ethyl 2-bromo-3-methoxypropionate,307 these products being intermediates in the synthesis of, respectively, / ,/ -dimethylserine, DL-threonine, and DL-serine.65... 

DL-Serine hydroxamic acid DL-Trypophan hydroxamic acid Phenylacetohydroxamic acid DL-Threonine hydroxamic acid... 

TEA-oleoyl hydrolyzed collagen TEA oleoyl sarcosinate TEA-palm kernel sarcosinate TEA-undecenoyl hydrolyzed collagen Tetrabutyl ammonium bromide Thenoyl methionate DL-Threonine L-Threonine Tricetylmonium chloride Tridecyl salicylate... 

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