2-Propoxybenzamide

In the title molecule, C10H13NO2, the amide –NH2 group is oriented toward the propoxy substituent and an intramolecular N—H⋯O hydrogen bond is formed between the N—H group and the propoxy O atom. The benzene ring forms dihedral angles of 12.41 (2) and 3.26 (2)° with the amide and propoxy group mean planes, respectively. In the crystal, N—H⋯O hydrogen bonds order pairs of molecules with their molecular planes parallel, but at an offset of 0.73 (2) Å to each other. These pairs are ordered into two types of symmetry-related columns extended along the a axis with the mean plane of a pair in one column approximately parallel to (-122) and in the other to (-1-22). The two planes form dihedral angle of 84.40 (1)°. Overall, in a three-dimensional network, the hydrogen-bonded pairs of molecules are either located in (-1-22) or (-122) layers. In one layer, each pair is involved in four C—H⋯O contacts, twice as a donor and twice as an acceptor. Additionally, there is a short C—H⋯C contact between a benzene C—H group and the amide π-system.

In the title molecule, C 10 H 13 NO 2 , the amide -NH 2 group is oriented toward the propoxy substituent and an intramolecular N-HÁ Á ÁO hydrogen bond is formed between the N-H group and the propoxy O atom. The benzene ring forms dihedral angles of 12.41 (2) and 3.26 (2) with the amide and propoxy group mean planes, respectively. In the crystal, N-HÁ Á ÁO hydrogen bonds order pairs of molecules with their molecular planes parallel, but at an offset of 0.73 (2) Å to each other. These pairs are ordered into two types of symmetryrelated columns extended along the a axis with the mean plane of a pair in one column approximately parallel to (122) and in the other to (122). The two planes form dihedral angle of 84.40 (1) . Overall, in a three-dimensional network, the hydrogen-bonded pairs of molecules are either located in (122) or (122) layers. In one layer, each pair is involved in four C-HÁ Á ÁO contacts, twice as a donor and twice as an acceptor. Additionally, there is a short C-HÁ Á ÁC contact between a benzene C-H group and the amide -system.
There is an intramolecular N13-H13A···O7 hydrogen bond within each molecule. The hydrogen bond N13-H13B···O12 (Table 1) (Table 1). Within two parallel layers, pairs are lying with an offset to each other without any noticeable, direct interaction between them. The parallel layers are at a distance of 3.69 (2) Å from each other. They are further apart than is found for a similar packing of 2-hydroxybenzamide [2.91 (1) Å] (Johnstone et al., 2010). Along the a axis the pairs are ordered in two symmetry related columns. The plane of the benzene ring (C1-C6) of the 2-propoxybenzamide forms an angle of 34.43 (2)° with the column axis.
For 2-ethoxybenzamide, a homologue of the title compound, a similar formation of inversion related molecular pairs in the crystal was reported (Pagola & Stephens, 2009). The noticable difference in the packing of the two molecules stems from the larger dihedral angle between the carboxamide group and the benzene ring in 2-ethoxybenzamide of [50.48 (2)°] than found for 2-propoxybenzamide. Thus, 2-ethoxybenzamide does not exhibit an intramolecular hydrogen bond, which leads to a different intermolecular bonding network as compared to the title compound.

Refinement
All the H-atom parameters were freely refined.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. 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 > σ(F 2 ) is used only for calculating R-factors(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.