N-(3-Methylphenyl)succinamic acid

In the crystal structure of the title compound, C11H13NO3, the conformations of the N—H and C=O bonds in the amide segment are anti to each other, and that of the amide H atom is anti to the meta-methyl group in the benzene ring. Furthermore, the conformations of the amide oxygen and the carbonyl O atom of the acid segment are also anti to the adjacent –CH2 groups. The C=O and O—H bonds of the acid group are syn to each other. In the crystal, the molecules are packed into infinite chains through intermolecular N—H⋯O and O—H⋯O hydrogen bonds.

In the crystal structure of the title compound, C 11 H 13 NO 3 , the conformations of the N-H and C O bonds in the amide segment are anti to each other, and that of the amide H atom is anti to the meta-methyl group in the benzene ring. Furthermore, the conformations of the amide oxygen and the carbonyl O atom of the acid segment are also anti to the adjacent -CH 2 groups. The C O and O-H bonds of the acid group are syn to each other. In the crystal, the molecules are packed into infinite chains through intermolecular N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds.
BSS thanks the University Grants Commission, Government of India, New Delhi, for the award of a research fellowship under its faculty improvement program.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BQ2189).

Comment
As a part of studying the effect of ring and side chain substitutions on the solid state geometry of anilides (Gowda et al., 2007;2009a,b), we report herein the crystal structure of N-(3-methylphenyl)succinamic acid (I). The conformations of N-H and C=O bonds in the amide segment are anti to each other. But the conformation of the amide oxygen and the carbonyl oxygen of the acid segment are syn to each other, contrary to the anti conformation observed in N-(4-Chlorophenyl)succinamic acid (II) (Gowda et al., 2009a) and N-(2-chlorophenyl)-succinamic acid (III) (Gowda et al., 2009b). The conformation of the amide hydrogen is anti to the meta-methyl group in the benzene ring, contrary to the syn conformation observed between the amide hydrogen and the ortho-Cl in (III).
The N-H···O and O-H···O intermolecular hydrogen bonds pack the molecules into infinite chains in the structure (Table 1, Fig.2).
The modes of interlinking carboxylic acids by hydrogen bonds is described elsewhere (Leiserowitz, 1976). The packing of molecules involving dimeric hydrogen bonded association of each carboxyl group with a centrosymmetrically related neighbor has also been observed (Jagannathan et al., 1994).

Experimental
The solution of succinic anhydride (0.01 mole) in toluene (25 ml) was treated dropwise with the solution of m-toluidine (0.01 mole) also in toluene (20 ml) with constant stirring. The resulting mixture was stirred for about one h 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 m-toluidine. The resultant solid N-(3-methylphenyl)-succinamic acid 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 by elemental analysis and characterized by its infrared and NMR spectra. The rod like colorless single crystals used in X-ray diffraction studies were grown in ethanolic solution by slow evaporation at room temperature.