data reports
Open access
The title compound, C5H6N4O, is approximately planar, with an angle of 11.04 (15)° between the planes of the pyrimidine ring and the non-H atoms of the carboximidamide unit. The molecule adopts an E configuration about the C=N double bond. In the crystal, adjacent molecules are linked by pairs of N—HO hydrogen bonds, forming inversion dimers with an R22(10) ring motif. The dimers are further linked via N—HN and O—HN hydrogen bonds into a sheet structure parallel to the ac plane. The crystal structure also features N—HO and weak C—HO hydrogen bonds and offset π–π stacking interactions between adjacent pyrimidine rings [centroid–centroid distance = 3.622 (1) Å].