2-Chloro-N-phenylacetamide

In the title compound, C8H8ClNO, the conformations of the N—H and C=O bonds are anti to each other, but the C—Cl and C=O bonds in the side chain are syn. The molecules are linked by N—H⋯O hydrogen bonds into infinite chains running in the [101] direction.

In the title compound, C 8 H 8 ClNO, the conformations of the N-H and C O bonds are anti to each other, but the C-Cl and C O bonds in the side chain are syn. The molecules are linked by N-HÁ Á ÁO hydrogen bonds into infinite chains running in the [101] direction.

Comment
In the present work, the structure of the title compoud, (I), 2-chloro-N-(phenyl)-acetamide (NPCA) has been determined, as part of a study of the effect of ring and side chain substitutions on the solid state geometry of aromatic amides (Gowda et al., 2007;2008). The conformations of the N-H and C=O bonds are anti to each other, but the C-Cl and C=O bonds in the side chain are syn to each other ( Fig. 1), similar to that observed in 2-chloro-N-(2-chlorophenyl)-acetamide (Gowda et al., 2007)and 2-chloro-N-(3-methylphenyl)-acetamide (Gowda et al., 2008) with similar bond parameters. Further, the amide group -NHCO-in (I) makes a dihedral angle of 16.0 (8)° with the phenyl ring.
Part of the packing for (I) viewed down the b axis is shown in Fig. 2. Infinite chains running along the base vector [101] are formed by N-H···O hydrogen bonds (Table 1).

Experimental
The title compound was prepared according to the literature method (Gowda et al., 2003) and colourless prisms of (I) were recrystallised from an ethanol solution.

Refinement
The H atoms were placed in calculated positions (C-H = 0.93Å, N-H = 0.86Å) and refined as riding with U iso (H) = 1.2U eq (C,N). Fig. 1. Molecular structure of (I) with displacement ellipsoids for the non-hydrogen atoms drawn at the 50% probability level.

Figures
supplementary materials sup-2  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 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.