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Two tautomeric forms of 2‐amino‐5,6‐dimethylpyrimidin‐4‐one
Author(s) -
Hall Victoria M.,
Bertke Jeffery A.,
Swift Jennifer A.
Publication year - 2016
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229616007403
Subject(s) - tautomer , psychology , chemistry , stereochemistry
Derivatives of 4‐hydroxypyrimidine are an important class of biomolecules. These compounds can undergo keto–enol tautomerization in solution, though a search of the Cambridge Structural Database shows a strong bias toward the 3 H ‐keto tautomer in the solid state. Recrystallization of 2‐amino‐5,6‐dimethyl‐4‐hydroxypyrimidine, C 6 H 9 N 3 O, from aqueous solution yielded triclinic crystals of the 1 H ‐keto tautomer, denoted form (I). Though not apparent in the X‐ray data, the IR spectrum suggests that small amounts of the 4‐hydroxy tautomer are also present in the crystal. Monoclinic crystals of form (II), comprised of a 1:1 ratio of both the 1 H ‐keto and the 3 H ‐keto tautomers, were obtained from aqueous solutions containing uric acid. Forms (I) and (II) exhibit one‐dimensional and three‐dimensional hydrogen‐bonding motifs, respectively.