The title compound, C19H21N3O, comprises a central pyrazole ring which is N-connected to an aldehyde group and C-connected twice to substituted benzene rings. The pyrazole ring is twisted on the C-C single bond, and the least-squares plane through this ring forms dihedral angles of 82.44 (5) and 4.52 (5)° with the (di-methyl-amino)-benzene and p-tolyl rings, respectively. In the crystal, weak C-H⋯O hydrogen bonds link mol-ecules into supra-molecular tubes along the b axis.
In the title compound, C24H20N2, the dihedral angles between the pyrazole ring and the pendant phenyl, toluoyl and phenyl-ethenyl rings are 41.50 (8), 4.41 (8) and 31.07 (8)°, respectively. In the crystal, inversion dimers linked by a π-π stacking inter-actions between the phenyl-ethenyl rings are observed [centroid-centroid separation = 3.5857 (9) Å].
The title compound, C20H20N2O, was studied as a part of our work on pyrazoline derivatives. It represents a trans-isomer. The central pyrazoline ring adopts an envelope conformation with the asymmetric C atom having the largest deviation of 0.107 (1) Å from the mean plane. It forms dihedral angles of 6.2 (1) and 86.4 (1)° with the adjacent p-tolyl and styrene groups, respectively. In the crystal, C-H⋯O inter-actions link mol-ecules into infinite chains along the c axis.
In the title compound, C18H18N2O2, the pyrazole ring has a twisted conformation on the CH-CH2 bond. The tolyl ring and the 4-meth-oxy-phenyl ring are inclined to the mean plane of the pyrazole ring by 4.40 (9) and 86.22 (9)°, respectively, while the two aromatic rings are inclined to one another by 88.75 (9)°. In the crystal, mol-ecules are linked via bifurcated C-H⋯(O,O) hydrogen bonds and C-H⋯π inter-actions, forming sheets lying parallel to the ab plane.