N-Cyclohexylbenzamide

The structure of the title compound, C13H17NO, features an anti disposition of the N—H and carbonyl groups. The amide group is twisted with respect to the benzene ring [N–C(=O)–C–C torsion angle = −30.8 (4)°]. In the crystal, C(4) chains propagating in [100] are formed by intermolecular N–H⋯O hydrogen bonds. Weak C—H⋯π interactions link the chains into sheets.

The structure of the title compound, C 13 H 17 NO, features an anti disposition of the N-H and carbonyl groups. The amide group is twisted with respect to the benzene ring [N-C( O)-C-C torsion angle = À30.8 (4) ]. In the crystal, C(4) chains propagating in [100] are formed by intermolecular N-HÁ Á ÁO hydrogen bonds. Weak C-HÁ Á Á interactions link the chains into sheets.

Comment
Benzamides are frequently used in the synthesis of new and potent anti-convulsant agents Leander et al., 1988;Diouf et al., 1997). The structure of the title compound, (I), a benzamide derivative, is reported herein (Fig. 1).
The benzene ring, adjacent to the carbonyl group, twisted with respect to the plane formed through the central amide group; the N1-C1-C2-C3 torsion angle = -30.8 (4) °. In the same way, the putative mirror plane through the cyclohexyl ring (having a chair conformation) is twisted away from the central plane; the O1-N1-C8-C11 torsion angle is 151.3 (4)°.
The anti-disposition of the NH and carbonyl groups allows for the formation of N-H···O hydrogen bonds which leads to the formation supramolecular chains aligned along the a axis, Fig. 2 and Table 1. These are connected into layers in the ab plane via C-H···π interactions, Fig. 2 and Table 1.

Experimental
A solution of cyclohexyl amine (0.458 µl, 4 mmol) in dichloromethane (15 ml) was treated dropwise with benzoyl chloride (0.463 µl, 4 mmol) in the presence of triethanol amine (5 ml) as a catalyst. The resulting mixture was stirred for 1 h. The precipitates that formed were filtered, dried and crystallized from methanol to yield colourless blocks of (I).

Refinement
The C-bound H atoms were geometrically placed (C-H = 0.93-0.98 Å) and refined as riding with U iso (H) = 1.2U eq (C).
The N-bound H atom was refined freely. In the absence of significant anomalous scattering effects, 1130 Friedel pairs were averaged in the final refinement.

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.