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1 H, 13 C and 17 O NMR study of chlorovanillins and some related compounds
Author(s) -
Kolehmainen Erkki,
Laihia Katri,
Knuutinen Juha,
Hyötyläinen Juha
Publication year - 1992
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.1260300311
Subject(s) - chemistry , chemical shift , substituent , carbon 13 nmr , coupling constant , proton , proton nmr , computational chemistry , stereochemistry , crystallography , physics , particle physics , quantum mechanics
1 H, 13 C and 17 O NMR chemical shifts and n J (H,H), 1 J (C,H) and 3 J (C‐6, H‐formyl) spin—spin coupling constants of chlorinated vanillins (3‐methoxy‐4‐hydroxybenzaldehydes) were determined. The variation in the long‐range 4 J (H,H) value between the formyl proton and an ortho ‐proton suggests that the ortho ‐substituent strongly forces the formyl group out of the aromatic plane. This can also be observed by considering the 3 J (C‐6,H‐formyl) values and the 13 C and 17 O NMR chemical shifts. The 17 O NMR chemical shifts show a linear correlation with the torsion angle of the formyl group calculated by molecular mechanics. The 13 C and 17 O NMR chemical shifts of the methoxyl group also possess strong predictive power in estimating the torsional characteristics of this group.