17O chemical shifts and deuterium isotope effects on 13C chemical shifts of intramolecularly hydrogen-bonded compounds

✍ Scribed by Lech Kozerski; Robert Kawȩcki; Piotr Krajewski; Brunon Kwiecień; David W. Boykin; Simon Bolvig; Poul Erik Hansen

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 133 KB
• Volume: 36
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199812)36:12<921::aid-omr392>3.0.co;2-r

✦ Synopsis

17O chemical shifts were measured in 40 enamines activated in the b-position by CxO, COO, NO 2 , SO and groups. Data for the oxygen-containing series of o-hydroxyacyl aromatics are also included for com-SO 2 parison. Intramolecular hydrogen bonding in the enamines is discussed in terms of the acceptor and donor groups and the separating link. 17O chemical shifts, the two-bond deuterium isotope shifts on C-a 13C shifts and 1H NH or OH chemical shifts are correlated to show the interrelations of these parameters in elucidating intramolecular hydrogen bonds and their strength in a wide variety of compounds. 17O chemical shifts in open-chain compounds are shown to reÑect intramolecular hydrogen bonding by a change to lower frequency whereas for Ðve-membered rings steric e †ects cause higher frequency chemical shifts.