Three-dimensional quantitative structure activity relationship (QSAR) of cytotoxic active 3,5-diaryl-4,5-dihydropyrazole analogs: a comparative molecular field analysis (CoMFA) revisited study

A second polymorph of (Z)-3-amino-4-(2-phenyl-hydrazinyl-idene)-1H-pyrazol-5(4H)-one

The mol­ecule of the title compound, C₉H₉N₅O, is approximately planar (the r.m.s. deviation of all non-H atoms is 0.08 Å). The amine substituent is pyramidal at the N atom. An intra­molecular N—H_hydrazine⋯O=C hydrogen bond is present. In the crystal, mol­ecules are connected via N—H⋯N and N—H⋯O hydrogen bonds, forming infinite layers parallel to (010). This polymorph is triclinic, space group P-1, whereas the previously reported form was monoclinic, space group P2₁/c [Elgemeie et al. (2013 ▶). Acta Cryst. E69, o187], with stepped layers and a significantly lower density.

Ethyl 5-amino-1-[(4-methyl-phen-yl)sulfon-yl]-1H-pyrazole-4-carboxyl-ate

In the title mol­ecule, C₁₃H₁₅N₃O₄S, the benzene and pyrazole rings are inclined to each other at 77.48 (3)°. Two amino H atoms are involved in bifurcated hydrogen bonds, viz. intra­molecular N—H⋯O and inter­molecular N—H⋯O(N). The inter­molecular hydrogen bonds link the mol­ecules related by translation in [100] into chains. A short distance of 3.680 (3) Å between the centroids of benzene and pyrazole rings from neighbouring mol­ecules shows the presence of π–π inter­actions, which link the hydrogen-bonded chains into layers parallel to the ab plane.