Hydrogen bonding in 2-amino-4-methoxy-6-methylpyrimidine, 2-benzylamino-4-benzyloxy-6-methyl-pyrimidine and 4-benzylamino-2,6-bis(benzyloxy)pyrimidine: pi-stacked chains of fused R-2(2)(8) rings, and centrosymmetric R-2(2)(8) dimers

Molecules of 2-amino-4-methoxy-6-methylpyrimidine, C6H9N3O, (I), lie on mirror planes in space group Pnma and are linked by two N-H...N hydrogen bonds [H...N = 2.26 and 2.34 Angstrom, N...N = 3.136 (2) and 3.212 (2) Angstrom, and N-H...N = 175 and 172degrees] into chains of edge-fused R-2(2) (8) rings, which themselves are linked into sheets by aromatic pi-pi-stacking interactions. In 2-benzylamino-4-benzyloxy-6-methylpyrimidine, C19H19N3O, (II), and 4-benzylamino-2,6-bis(benzyloxy)pyrimidine, C25H23N3O2, (III), the molecules are linked by paired N-H...N hydrogen bonds [H...N = 2.16 Angstrom, N...N = 3.039 (2) Angstrom and N-H...N = 165degrees in (II); H...N = 2.15 Angstrom, N...N = 2.980 (2) Angstrom and N-H...N = 176degrees in (III)] into centrosymmetric R-2(2) (8) dimers, with no direction-specific interactions between these dimeric units.