A solid solution of ethyl and d (3)-methyl 2-[(4-meth­yl­pyridin-2-yl)amino]-4-(pyridin-2-yl)thia­zole-5-carboxyl­ate

The synthesis of ethyl 2-[(4-methyl­pyridin-2-yl)amino)-4-(pyridin-2-yl)thia­zole- 5-carboxyl­ate via the Hantzsch reaction and partial in situ transesterification during recrystallization from methanol-d (4) to the d (3)-methyl ester, resulting in the title solid solution, ethyl 2-[(4-methyl­pyridin-2-yl)amino)-4-(pyridin-2-yl)thia­zole-5-carboxyl­ate–d (3)-methyl 2-[(4-methyl­pyridin-2-yl)amino)-4-(pyridin-2-yl)thia­zole-5-carboxyl­ate (0.88/0.12), 0.88C(17)H(16)N(4)O(2)S·0.12C(16)D(3)H(11)N(4)O(2)S, is reported. The refined ratio of ethyl to d (3)-methyl ester in the crystal is 0.880 (6):0.120 (6). The pyridine ring is significantly twisted out of the plane of the approximately planar picoline thia­zole ester moiety. N—H⋯N hydrogen bonds between the secondary amino group and the pyridine nitro­gen atom of an adjacent symmetry-related mol­ecule link the mol­ecules into polymeric hydrogen-bonded zigzag tapes extending by glide symmetry in the [001] direction. There is structural evidence for intra­molecular N⋯S chalcogen bonding and inter­molecular weak C—H⋯O hydrogen bonds between adjacent zigzag tapes.