N-(3-Chloro-2-methylphenyl)succinamic acid

In the title compound, C11H12ClNO3, the dihedral angle between the benzene ring and the amide group is 44.9 (2)°. In the crystal, molecules form inversion dimers via pairs of O—H⋯O hydrogen bonds. These dimers are further linked into sheets parallel to (013) via N—H⋯O hydrogen bonds.

In the title compound, C 11 H 12 ClNO 3 , the dihedral angle between the benzene ring and the amide group is 44.9 (2) . In the crystal, molecules form inversion dimers via pairs of O-HÁ Á ÁO hydrogen bonds. These dimers are further linked into sheets parallel to (013) via N-HÁ Á ÁO hydrogen bonds.
Further, the conformations of the amide oxygen and the carboxyl oxygen of the acid segments are anti to each other and both are anti to the H atoms on the adjacent -CH 2 groups.
The C═O and O-H bonds of the acid groups are in syn position to each other, similar to that observed in (I).
The dihedral angle between the phenyl ring and the amide group is 44.9 (2)°, compared to the values of 40.6 (2)° and 44.9 (3)° in the two independent molecules of (I).

Experimental
The solution of succinic anhydride (0.01 mole) in toluene (25 ml) was treated dropwise with the solution of 3-chloro-2methylaniline (0.01 mole) also in toluene (20 ml) with constant stirring. The resulting mixture was stirred for about one hour and set aside for an additional hour at room temperature for completion of the reaction. The mixture was then treated with dilute hydrochloric acid to remove the unreacted 3-chloro-2-methyl-aniline. The resultant (the title compound) was filtered under suction and washed thoroughly with water to remove the unreacted succinic anhydride and succinic acid. It was recrystallized to constant melting point from ethanol. The purity of the compound was checked and characterized by its infrared spectrum.
Plate like colorless single crystals used in X-ray diffraction studies were grown in ethanolic solution by slow evaporation of the solvent at room temperature.

Refinement
All H atoms were located in a difference map. The coordinates of the H atoms bonded to N and O were refined with  (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).  Molecular packing of the title compound with hydrogen bonding shown as dashed lines. 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.