4-(Cyclopropanecarboxamido)benzoic acid

In the title compound, C11H11NO3, the dihedral angle between the benzene ring and the cyclopropane ring is 63.2 (1)°. In the crystal, molecules are linked through classical cyclic carboxylic acid O—H⋯O hydrogen-bond interactions [graph set R 2 2(8)] giving centrosymmetric dimers which are extended along the b-axis direction through amide N—H⋯O hydrogen-bond interactions, giving one-dimensional ribbon structures. Weak C—H⋯O interactions are also present in the structure.

In the title compound, C 11 H 11 NO 3 , the dihedral angle between the benzene ring and the cyclopropane ring is 63.2 (1) . In the crystal, molecules are linked through classical cyclic carboxylic acid O-HÁ Á ÁO hydrogen-bond interactions [graph set R 2 2 (8)] giving centrosymmetric dimers which are extended along the b-axis direction through amide N-HÁ Á ÁO hydrogen-bond interactions, giving one-dimensional ribbon structures. Weak C-HÁ Á ÁO interactions are also present in the structure.

Comment
The title compound, C 11 H 11 NO 3 , has been of great interest for many years because it has different biological activities and been used as a ligand in the synthesis of various Cathepsin-S reversible inhibitor compounds (Gediya et al., 2008). In order to obtain a new potentially active histone deacetylase inhibitor, the title compound was synthesized and its crystal structure is reported here. In this molecule ( Fig. 1), the dihedral angle between the benzene ring and the cyclopropane ring is 63.2 (1)°. In the crystal, molecules are linked through classic cyclic carboxylic acid O-H···O hydrogen-bonding interactions [graph set R 2 2 (8) (Etter et al., 1990)] giving centrosymmetric dimers which are extended along b through amide N-H···O hydrogen-bonding interactions (Table 1), giving one-dimensional ribbon structures (Fig. 2). Present also in the structure are weak C-H···O interactions to both amide and carboxyl O-acceptors.

Experimental
Cyclopropanecarboxylic acid (500mg, 5.8 mmol) and N, N′-carbonyldiimidazole (1.035 g, 6.38 mmol) were dissolved in acetonitrile (5ml) and the solotion was stirred for 0.5h, then added dropwise into 5 ml of an acetonitrile solution of 4aminobenzoic acid (1.59 g, 11.6 mmol). This solution was then added dropwise to 5 ml of a trifluoroacetic acid solution in acetonitrile (727 mg, 6.38 mmol) which was stirred for 1h. The resulting mixture was dried, then diluted with ethyl acetate, washed with water, then dried in vacuo. The residue was purified by colunm chromatography (CH 3 OH/CH 2 Cl 2 , 5/95). Crystals suitable for X-ray diffraction were grown in a dilute CH 3 OH/CH 2 Cl 2 solution at room temperature by slow evaporation.

Refinement
Hydrogen atoms on O and N were located in a difference-Fourier map and both coordinates and isotropic displacement parameters were refined. Other H-atoms were placed in idealized positions and allowed to ride on their respective parent atoms, with C-H = 0.93 Å (aromatic) or 0.97 or 0.98 Å (aliphatic) and U iso (H) = 1.2U eq (C).

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