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Configurational assignment of β‐phenylaspartic acids in solution by 1 H and 13 C nuclear magnetic resonance
Author(s) -
Barrelle M.,
Gey C.,
Béguin C. G.
Publication year - 1988
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260260809
Subject(s) - chemistry , vicinal , diastereomer , coupling constant , molecule , resonance (particle physics) , stereochemistry , carbon 13 , crystallography , nuclear magnetic resonance , atomic physics , organic chemistry , physics , nuclear physics , particle physics
Vicinal 3 J (HH) and 3 J ( 13 CH) coupling constants are reported for the two diastereoisomers of β‐phenylaspartic acid at various pH values. A comparison between these coupling constants and those expected from the possible conformations of these molecules allows configurational assignments to be made. In strong acidic medium we observed intermediate values for 3 J (HH) for both isomers, for one isomer two intermediate values for 3 J (Co‐α, H‐β) and 3 J (Co‐β, H‐α), and for the other isomer a very small value for 3 J (CO‐α, H‐β) and an intermediate value for 3 J (Co‐β, H‐α). The discussion shows that the former has the RR/SS configuration and the latter the RS/SR configuration.