Threonine chemical-shifts data

C-N.m.r. Chemical-shift Data for Various a- and /i-D-Clycosyl-L-threonine Derivatives... 

C-N.m.r. Chemical-shift Data for the Anomeric-Carbon Atoms and C, and Coupling Constants ( /ch) Measured for Selected Gland /S-D-Glycosyl-L-threonine Model Compounds19- 1,82-84... 

The presence of two different probes, namely, Gal C-l and Thr C7, giving rise to signals situated in two different, uncrowded regions of the spectrum, with chemical-shift differences (AdC-l up to 8.35 p.p.m., and Ad Thr C7, up to 6.7 p.p.m.), allows the facile detection of any racemiza-tion occurring at either, or both, of the asymmetric carbon atoms of the threonine. It would be difficult to distinguish a-D-Gal — L-Thr (27) from its P analog (28), or / -D-Gal — D-alloThr (58) from / -D-Gal — L-alloThr (56), on the basis of the anomeric-carbon chemical-shifts only. However, they can be differentiated on the basis of Thr Cr chemical-shift data. It should be noted that neither optical rotation nor -n.m.r. spectroscopy could have elucidated this point.85... 

PS may be assigned to a glycine (Gly) or threonine (Thr), because PS is close to both the expected chemical shift data sets ... 

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