Supra­molecular aggregation in three 4-aryl-6-(1H-indol-3-yl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitriles

Both 6-(1H-indol-3-yl)-3-methyl-4-(4-methyl­phen­yl)-1-phen­yl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile and 6-(1H-indol-3-yl)-3-methyl-4-(4-methoxy­phen­yl)-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile crystallize from dimethyl­formamide solutions as stoichiometric 1:1 solvates, viz. C₂₉H₂₁N₅·C₃H₇NO, (I), and C₂₉H₂₁N₅O·C₃H₇NO, (II), respectively; however, 6-(1H-indol-3-yl)-3-methyl-1-phenyl-4-(3,4,5-trimethoxy­phen­yl)-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile, C₃₁H₂₅N₅O₃, (III), crystallizes in the unsolvated form. The heterocyclic components of (I) are linked by C—H...π(arene) hydrogen bonds to form cyclic centrosymmetric dimers, from which the solvent mol­ecules are pendent, linked by N—H...O hydrogen bonds. In (II), the heterocyclic components are linked by a combination of C—H...N and C—H...π(arene) hydrogen bonds into chains containing two types of centrosymmetric ring, and the pendent solvent mol­ecules are linked to these chains by N—H...O hydrogen bonds. Mol­ecules of (III) are linked into simple C(12) chains by an N—H...O hydrogen bond, and these chains are weakly linked into pairs by an aromatic π–π stacking inter­action.

A three-dimensional hydrogen-bonded framework in 2-amino-4,6-bis­[N-methyl-N-(4-methyl­phenyl)amino]­pyrimidine-5-carbaldehyde and hydrogen-bonded sheets in 2-amino-4-(indolin-1-yl)-6-methoxy­pyrimidine-5-carbaldehyde

The mol­ecules of 2-amino-4,6-bis­[N-methyl-N-(4-methyl­phenyl)amino]pyrimidine-5-carbaldehyde, C₂₁H₂₃N₅O, (I), and 2-amino-4-(indolin-1-yl)-6-methoxy­pyrimidine-5-carbaldehyde, C₁₄H₁₄N₄O₂, (II), which crystallizes with Z' = 2 in the space group P, exhibit polarized electronic structures. Mol­ecules of (I) are linked by a combination of N-H...O, C-H...O and C-H...[pi](arene) hydrogen bonds into a three-dimensional framework structure, while those of (II) are linked into sheets by a combination of two N-H...O hydrogen bonds and one N-H...[pi](arene) hydrogen bond.

(E)-3-{2-Amino-4-eth­oxy-6-[N-(4-meth­oxy­phen­yl)-N-methyl­amino]pyrimidin-5-yl}-1-phenyl­prop-2-en-1-one: a boat-shaped pyrimidine ring and a chain of hydrogen-bonded R⁴₂(8) and R²₂(20) rings

In the title compound, C₂₃H₂₄N₄O₃, the pyrimidine ring adopts an almost perfect boat conformation, and the bond distances provide evidence for some polarization of the mol­ecular-electronic structure. Two independent N-H...O hydrogen bonds link the mol­ecules into chains of edge-fused R²₄(8) and R²₂(20) rings.