Ethyl 2-benzyl-3-[3-(4-chloro-phen-yl)-1-phenyl-1H-pyrazol-4-yl]-4,6-dioxo-5-phenyl-octa-hydro-pyrrolo-[3,4-c]pyrrole-1-carboxyl-ate

3-(4-Chlorophenyl)-5-[4-(methylsulfanyl)phenyl]-1H-pyrazole

In the title compound, C16H13ClN2S, the pyrazole ring is almost planar with an r.m.s. deviation of 0.0457 Å which forms dihedral angles of 2.875 (4) and 84.83 (7)° with the chloro-substituted benzene ring and the methylsulfanyl-substituted ring, respectively. In the crystal, N—H...N and C—H...Cl hydrogen bonds contribute to the formation of a three-dimensional network. In addition, several offset π–π stacking interactions are also present.

Characterization of biaryl torsional energetics and its treatment in OPLS all-atom force fields

The frequency of biaryl substructures in a database of approved oral drugs has been analyzed. This led to designation of 20 prototypical biaryls plus 10 arylpyridinones for parametrization in the OPLS all-atom force fields. Bond stretching, angle-bending, and torsional parameters were developed to reproduce the MP2 geometries and torsional energy profiles. The transferability of the new parameters was tested through their application to three additional biaryls. The torsional energetics for the 33 biaryl molecules are analyzed and factors leading to preferences for planar and nonplanar geometries are identified. For liquid biphenyl, the computed density and heat of vaporization at the boiling point (255 °C) are also reported.