摘要:

Abstract13C NMR spectra of 27‐hydroxyfriedelane, kokoonol (27‐hydroxyfriedelan‐3‐one) and kokoononol (27‐hydroxyfriedelan‐3,21‐dione) have been recorded and signals assigned using the off‐resonance decoupling, inversion recovery and lanthanide induced s

ISSN:0030-4921    

DOI:10.1002/mrc.1270180112

出版商:John Wiley&Sons Limited    

年代:1982

数据来源: WILEY

摘要:

AbstractSubstituent effects on the13C and1H chemical shifts have been studied for derivatives of 3‐benzylidene‐2, 4‐pentanedione. A significant correlation has been found between chemical shifts of theZcarbonyl group (C‐2) and Hammett constants, while no correlation has been found for theEcarbonyl group (C‐4). Attempts have been made to determine the structural factors which influence these effects. The conformation of 3‐benzylidene‐2, 4‐pentanediones has been determined by13C and1H N

ISSN:0030-4921    

DOI:10.1002/mrc.1270180113

出版商:John Wiley&Sons Limited    

年代:1982

数据来源: WILEY

摘要:

AbstractLarge deuterium isotope effects of both signs have been observed on the13C nuclear shielding in proton‐chelating tautomeric forms of β‐thioxoketones, and small isotope effects of both signs have been found in related forms of Schiff's bases of salicylaldehydes. These effects are interpreted in terms of shifts in the tautomeric equilibria on deuterium substitution of the enolic proton. The observation of deuterium isotope effects is suggested as a useful method for the detection of fast tautomeric equilibria in systems of the following t

ISSN:0030-4921    

DOI:10.1002/mrc.1270180114

出版商:John Wiley&Sons Limited    

年代:1982

数据来源: WILEY

ISSN:0030-4921    

DOI:10.1002/mrc.1270180101

出版商:John Wiley&Sons Limited    

年代:1982

数据来源: WILEY