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Configurational assignment of β‐fluoro‐β‐phenylamines using 1 H and 19 F NMR
Author(s) -
Hamman Sylvain,
Benaïssa Tahar,
Béguin Claude 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.1260260718
Subject(s) - chemistry , protonation , diastereomer , amine gas treating , chemical shift , stereochemistry , carbon 13 nmr , tertiary amine , ammonium , alkane stereochemistry , crystallography , medicinal chemistry , crystal structure , organic chemistry , ion
The 1 H and 19 F NMR parameters [δH‐α, δH‐β, δ F , 3 J (HH) and 3 J (FH)] of β‐fluoro‐β‐phenylamines of the two series PhCHFCH 2 NR 1 R 2 and PhCHFCH(R)‐NR 1 R 2 in CDCl 3 (amine form) and in CD 3 OD (protonated amine form) and those of the corresponding β‐hydroxy‐β‐phenylamines were measured. It is shown that for the protonated amines the predominant conformation is that in which the ammonium group is antiperiplanar to the phenyl group, especially for tertiary amines. Assignment of the diastereoisomers of the PhCHFCHRNR 1 R 2 series can be made with the NMR parameters of the protonated amines: high (low) 3 J (HH) values, low (high) 3 J (FH) values, 19 F chemical shifts to high (low) frequency are those for the threo ( erythro ) isomers.