Crystal structure of 4-amino-5-fluoro-2-oxo-2,3-dihydropyrimidin-1-ium 3-hydroxypyridine-2-carboxylate

• Main Authors: Ammasai Karthikeyan, Packianathan Thomas Muthiah, Franc Perdih
• Format: Article
• Language: English
• Published: International Union of Crystallography 2014-11-01
• Series: Acta Crystallographica Section E
• Subjects: crystal structure; antifungal drug; 5-fluorocytosine; hydrogen bonding; supramolecular structure; hydrogen-bond ring motifs
• Online Access: http://scripts.iucr.org/cgi-bin/paper?S1600536814021898

The asymmetric unit of the title salt, C4H5FN3O+·C6H4NO3−, contains one 4-amino-5-fluoro-2-oxo-2,3-dihydropyrimidin-1-ium (5-fluorocytosinium, 5FC) cation and a 3-hydroxypicolinate (3HAP) anion. The 4-amino-5-fluoro-2-oxo-2,3-dihydropyrimidine molecule is protonated at one of the pyrimidine N atoms. The typical intramolecular N—H...F and O—H...O S(5) and S(6) hydrogen-bond ring motifs are observed in the cations and anions. The protonated N atom and 2-amine group of the 5FC cation interact with the 3HPA anion through a pair of nearly parallel N—H...O hydrogen bonds, forming a robust R22(8) ring motif. The ions are further linked by N—H...N, O—H...O, N—H...O and C—H...O hydrogen bonds, generating R22(7), R33(12) and R65(18) ring motifs, respectively, leading to supramolecular wave-like sheets parallel to (010). The crystal structure is further stabilized by C—H...π interactions, generating a three-dimensional architecture.