Premium
1 H and 13 C NMR study of dihydro derivatives of methylphenobarbital
Author(s) -
Rautio Marjatta,
Rahkamaa Erkki
Publication year - 1981
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.1270150112
Subject(s) - sodium borohydride , chemistry , ring (chemistry) , spectral line , borohydride , nmr spectra database , carbon 13 nmr , group (periodic table) , medicinal chemistry , stereochemistry , crystallography , organic chemistry , physics , catalysis , astronomy
Sodium borohydride reduction of methylphenobarbital leads to the formation of two different dihydroderivatives, reduced either in position 4 or position 6. The structures of the derivatives have been determined through analysis of the 1 H and 13 C NMR spectra of phenobarbital, methylphenobarbital and their derivatives. Detailed interpretation of the spectra and the resulting spectral parameters indicate conformations where the hydroxyl groups are axial and trans to the ethyl group. In these configurations the phenyl ring becomes equatorial. The results also allow an unambiguous assignment of the resonances of the phenyl carbons 2′(6′) and 3′(5′) of phenobarbital and the carbonyl carbons 4 and 6 of methylphenobarbital, differing interpretations having been previously advanced in the literature.