2-Chloro-N-{5-[(4R,5R,10S)-dehydroabiet-4-yl]-1,3,4-thiadiazol-2-yl}benzamide

There are two independent molecules in the asymmetric unit of the title compound, C28H32ClN3OS (systematic name: 2-chloro-N-{5-[(1R,4aS,10aR)-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthren-1-yl]-1,3,4-thiadiazol-2-yl}benzamide). In each molecule, the cyclohexyl ring attached to the thiadiazole fragment adopts a classic chair conformation with two of its two methyl groups in the axial positions. In the crystal, pairs of intermolecular N—H⋯N hydrogen bonds link the molecules into centrosymmetric dimers, which are further linked via C—H⋯π interactions.


Related literature
For background to the uses of rosin, see: Song (2004). For the isolation of dehydroabietic acid, the major component of disproportionated rosin, see: Xu et al. (2009). For the biological activity of dehydroabietic derivatives, see: Sepulveda et al. (2005). For the synthesis of the title compound, see: Liu et al.   Table 1 Hydrogen-bond geometry (Å , ).
Cg is the centroid of the C23-C28 2-chlorophenyl ring. Rosin, known as an important chemical raw material, is widely used in papermaking, adhesives, paint, printing ink, rubber, food, and other industries (Song, 2004). Dehydroabietic acid is the dominant component of disproportionated rosin produced by catalytic disproportionation of rosin. Therefore, the search for novel bioactive compounds and the study of their pharmacological properties constitute a matter of current interest. Hence, a series of dehydroabietic acid derivatives bearing heterocyclic ring were synthesized and their properties in many fileds have been researched. Herein, we report the crystal structure of the title compound.
The asymmetric unit of the title compound is shown in Fig. 1. There are two independent molecules [A and B] and all bond lengths and angles are within normal ranges (Allen et al., 1987). In each molecule, the cyclohexyl ring having the thiadiazole fragment adopts a classic chair conformation with two methyl groups in the axial positions. The crystal packing ( Fig. 2) is stabilized by intermolecular N-H···N hydrogen bonds between the hydrogen of the amide group and the thiadiazole N atom (see; Table 1). The crystal packing (Fig. 2) is further stabilized by intermolecular C-H···π interactions between a cyclohexyl H atom and the 2-chlorophenyl ring (Table 1; Cg is the centroid of the C23-C28 2-chlorophenyl ring).

Refinement
All H atoms were positioned geometrically and refined using a riding model with C-H = 0.93-0.98 Å and N-H=0.86 Å with U iso (H) = 1.5Ueq(C) for methyl H atoms and Uiso(H) = 1.2Ueq(C) for all other H atoms.
supplementary materials sup-2 Figures Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are presented as a small spheres of arbitrary radius.  as those based on F, and R-factors based on ALL data will be even larger.