Bis{4-[(1,3-benzodioxol-5-yl)meth­yl]piperazin-1-yl}methane

In the title compound, C₂₅H₃₂N₄O₄, both piperazine rings adopt a chair conformation. One of dioxolane ring systems is essentially planar [dihedral angle = 0.9 (2)°] while the other adopts a slightly disordered envelope conformation, the mean plane of the dioxolane ring being twisted by 3.6 (2)° from that of the benzene ring. The dihedral angle between the benzene rings is 69.9 (5)°. No classical hydrogen bonds were observed.

1-[4-(4-Hy­droxy­phen­yl)piperazin-1-yl]ethanone

In the title compound, C₁₂H₁₆N₂O₂, the piperazine ring has a chair conformation. The dihedral angle between the mean planes of the benzene ring and the acetyl group is 48.7 (1)°. In the crystal, mol­ecules are linked via O—H...O hydrogen bonds, forming chains propagating along [010].

4-Methyl-N-(4-nitro­benzyl­idene)piperazin-1-amine

In the title compound, C₁₂H₁₆N₄O₂, the piperazine ring is in a slightly distorted chair conformation. In the mol­ecule, the mean plane of the nitro group is twisted by 8.0 (3)° from that of the benzene ring. Also, the mean plane of the 2-nitro­benzyl ring is twisted slightly from that of the piperazine ring, with an N—N=C—C torsion angle of −176.24 (11)°. In the crystal, pairs of weak C—H...O inter­actions link the mol­ecules into dimers approximately along [010].

N-(1H-Indol-3-yl­methyl­idene)-4-methyl­piperazin-1-amine

In the title compound, C₁₄H₁₈N₄, the piperazine ring is in a slightly distorted chair conformation. The indole ring system is twisted from the piperazine ring, making a dihedral angle of 7.27 (11)°. In the crystal, N—H...N hydrogen bonds link mol­ecules into chains along [10-1].