In each of ethylN-2-amino-5-formyl-6-[methyl(phenyl)amino]pyrimidin-4-yl}glycinate, C16H19N5O3, (I),N-2-amino-5-formyl-6-[methyl(phenyl)amino]pyrimidin-4-yl}glycinamide, C14H16N6O2, (II), and ethyl 3-amino-N-2-amino-5-formyl-6-[methyl(phenyl)amino]pyrimidin-4-yl}propionate, C17H21N5O3, (III), the pyrimidine ring is effectively planar, but in each of methylN-2-amino-6-[benzyl(methyl)amino]-5-formylpyrimidin-4-yl}glycinate, C16H19N5O3, (IV), ethyl 3-amino-N-2-amino-6-[benzyl(methyl)amino]-5-formylpyrimidin-4-yl}propionate, C18H23N5O3, (V), and ethyl 3-amino-N-[2-amino-5-formyl-6-(piperidin-4-yl)pyrimidin-4-yl]propionate, C15H23N5O3, (VI), the pyrimidine ring is folded into a boat conformation. The bond lengths in each of (I)–(VI) provide evidence for significant polarization of the electronic structure. The molecules of (I) are linked by paired N—H...N hydrogen bonds to form isolated dimeric aggregates, and those of (III) are linked by a combination of N—H...N and N—H...O hydrogen bonds into a chain of edge-fused rings. In the structure of (IV), molecules are linked into sheets by means of two hydrogen bonds, both of N—H...O type, in the structure of (V) by three hydrogen bonds, two of N—H...N type and one of C—H...O type, and in the structure of (VI) by four hydrogen bonds, all of N—H...O type. Molecules of (II) are linked into a three-dimensional framework structure by a combination of three N—H...O hydrogen bonds and one C—H...O hydrogen bond.
在 N-2-氨基-5-甲酰基-6-[甲基(苯基)氨基]嘧啶-4-基}甘氨酸乙酯(C16H19N5O3,(I))、N-2-氨基-5-甲酰基-6-[甲基(苯基)氨基]嘧啶-4-基}甘氨酰胺C14H16N6O2,(II) 和 3-氨基-N-2-氨基-5-甲酰基-6-[甲基(苯基)氨基]嘧啶-4-基}丙酸乙酯,C17H21N5O3,(III) 中,嘧啶环实际上是平面的、但在 N-2-氨基-6-[苄基(甲基)氨基]-5-甲酰基嘧啶-4-基}甘氨酸甲酯(C16H19N5O3,(IV))、3-氨基-N-2-氨基-6-[苄基(甲基)氨基]-5-甲酰基嘧啶-4-基}丙酸乙酯(C18H23N5O3,(III)C18H23N5O3,(V) 和 3-氨基-N-[2-氨基-5-甲酰基-6-(哌啶-4-基)嘧啶-4-基]丙酸乙酯,C15H23N5O3,(VI),嘧啶环折叠成舟形构象。(I)-(VI)中每个分子的键长都证明了电子结构的显著极化。(I)的分子通过成对的 N-H...N氢键连接形成孤立的二聚体,而(III)的分子则通过 N-H...N和 N-H...O氢键组合连接成边缘融合的环链。在(IV)的结构中,分子通过两个氢键(均为 N-H...O 型)连接成片状;在(V)的结构中,分子通过三个氢键(两个 N-H...N 型和一个 C-H...O 型)连接成片状;在(VI)的结构中,分子通过四个氢键(均为 N-H...O 型)连接成片状。(II)的分子通过三个 N-H...O 型氢键和一个 C-H...O 型氢键组合连接成三维框架结构。