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PMR studies of the deuteration and hydration of 4‐piperidones
Author(s) -
Hassan M. M. A.,
Casy A. F.
Publication year - 1969
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270010506
Subject(s) - ketone , chemistry , nitrogen atom , ring (chemistry) , salt (chemistry) , base (topology) , nitrogen , medicinal chemistry , population , organic base , computational chemistry , organic chemistry , mathematics , mathematical analysis , demography , sociology
PMR spectra of substituted 4‐piperidones in base and salt forms in D 2 O, water and other solvents are reported, and spectral characteristics interpreted in terms of equilibria between free ketone and 4,4‐dideuteroxy (or hydroxy) forms. It is shown that 1‐mono and 1,3‐disubstituted‐4‐piperidones exist extensively as the corresponding dideuteroxy (or hydrated) species in D 2 O (or H 2 O) provided the ring nitrogen atom is positively charged, and that 3‐substituents decrease the population of these forms. The facile D/H exchange of α‐protons in the piperidone bases is also demonstrated.