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Investigation of the structure and 13 C NMR spectrum of 5‐phenylbarbituric acid
Author(s) -
De Meester Patrice,
Chu Shirley S. C.,
Jovanovic Misa V.,
Biehl Edward R.
Publication year - 1986
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.5570230207
Subject(s) - chemistry , monoclinic crystal system , molecule , crystallography , enol , nuclear magnetic resonance spectroscopy , hydrogen bond , crystal structure , stereochemistry , organic chemistry , catalysis
Crystals of 5‐phenylbarbituric acid, 2 , are monoclinic, space group C2/c. There are 8 molecules in the unit cell of dimensions a = 20.218(3), b = 7.477(1), c, = 12.443(2), β = 111.54° and V = 1749.6(4) Å 3 . Full‐matrix least‐squares refinement has reached R = 0.039. This is the first barbiturate reported to exist in the enol form in the solid state. There is extensive hydrogen bonding between adjacent molecules which gives rise to very dense crystals. The 13 C‐nmr spectroscopy shows that 2 exists in both enol and keto forms in DMSO solution.