Two N-substituted 3,5-diphenyl-2-pyrazoline-1-thiocarboxamides.

The structures of N-ethyl-3-(4-fluorophenyl)-5-(4-methoxyphenyl)-2-pyrazoline-1-thiocarboxamide, C19H20FN3OS, (I), and 3-(4-fluorophenyl)-N-methyl-5-(4-methylphenyl)-2-pyrazoline-1-thiocarboxamide, C18H18FN3S, (II), have similar geometric parameters. The methoxy/methyl-substituted phenyl groups are almost perpendicular to the pyrazoline (pyraz) ring [interplanar angles of 89.29 (8) and 80.39 (10) degrees for (I) and (II), respectively], which is coplanar with the fluorophenyl ring [interplanar angles of 5.72 (9) and 10.48 (10) degrees]. The pyrazoline ring approximates an envelope conformation in both structures, with the two-coordinate N atom involved in an intramolecular N-H...N(pyraz) interaction. In (I), N-H...O and C-H...S intermolecular hydrogen bonds are the primary interactions, whereas in (II), there are no intermolecular hydrogen bonds.