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17 O NMR spectroscopy: Intramolecular hydrogen bonding in hydroxypyridine carboxy esters
Author(s) -
Boykin David W.,
Kumar Arvind
Publication year - 1992
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570290101
Subject(s) - chemistry , intramolecular force , nuclear magnetic resonance spectroscopy , hydrogen bond , spectroscopy , hydrogen , organic chemistry , molecule , physics , quantum mechanics
Natural abundance 17 O nmr chemical shift data for 8 aryl esters and 10 pyridine carboxy esters, including 6 ortho ‐hydroxy esters, recorded in acetomitrile at 75° are reported. The carbonyl group 17 O nmr chemical shift data for methyl 2‐, 3‐ and 4‐pyridinecarboxylate are correlated with σ + constants. The hydrogen bonding component (Δδ HB ) to the ester carbonyl 17 O nmr chemical shift for the intramolecular hydrogen bonded ortho ‐hydroxy systems are 9.8 ppm, 13.6 ppm and 4.3 ppm for benzoates, 2‐pyridinecarboxylates and 4‐pyridinecarboxylates, respectively. The relationships of the ester Δδ HB values to other hydrogen bond acceptor Δδ HB values are discussed.