Crystal structures and Hirshfeld surface analyses of 2-[(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(pyridin-2-yl)acetamide and 2-[(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(pyrazin-2-yl)acetamide

Abstract

In the title compounds, C11H12N6OS (I) and C10H11N7OS (II), the diaminopyrimidine ring makes dihedral angles of 71.10 (9)° with the pyridine ring in (I) and 62.93 (15)° with the pyrazine ring in (II). The ethanamine group, –CH2–C(=O)–NH– lies in the plane of the pyridine and pyrazine rings in compounds (I) and (II), respectively. In both compounds, there is an intramolecular N—H...N hydrogen bond forming an S(7) ring motif and a short C—H...O interaction forming an S(6) loop. In the crystals of both compounds, molecules are linked by pairs of N—H...N hydrogen bonds, forming inversion dimers with R22(8) ring motifs. In (I), the dimers are linked by N—H...O and N—H...N hydrogen bonds, forming layers parallel to (1\overline{1}\overline{1}). The layers are linked by offset π–π interactions [intercentroid distance = 3.777 (1) Å], forming a three-dimensional supramolecular structure. In (II), the dimers are linked by N—H...O, N—H...N and C—H...O hydrogen bonds, also forming a three-dimensional supramolecular structure.

Keywords

• crystal structure
• 4,6-diaminopyrimidine
• sulfanyl
• acetamide
• pyridine
• pyrazine
• hydrogen bonding
• offset π-π interactions
• Hirshfeld surface