4′-Acetyl-3′′-carbamoyl-[1,1′:3′,1′′-terphenyl]-2-carboxylic acid

In the title m-terphenyl derivative, C22H17NO4, the dihedral angles between the aromatic rings of the benzoic acid–acetophenone, acetophenone–benzamide and benzoic acid–benzamide units are 45.39 (8), 48.02 (8) and 42.93 (8)°, respectively. The carbamoyl and carboxyl groups are disordered with a refined occupancy ratio of 0.558 (15):0.442 (15). In the crystal, molecules are linked through O—H⋯O and N—H⋯O hydrogen bonds between terminal carboxyl and carbamoyl groups in a bidentate manner, and antiparallel helices are formed which extend along the b-axis direction.

This work was partly supported by Grants-in-Aid (No. 24590141 to YI) for Scientific Research from the Japan Society for the Promotion of Science. We acknowledge the University of Shizuoka for instrumental support.
supplementary materials   (Table 1), and align parallel to the b axis ( Fig. 2 and 3).

Experimental
Methyl 4′-acetyl-3′′-carbamoyl-[1,1′:3′,1′′-terphenyl]-2-carboxylate (2.70 mmol) was dissolved in a mixture of 10 M NaOH (40 ml), 2-propanol (20 ml) and THF (20 ml), which was then refluxed overnight. The reaction mixture was cooled to room temperature, and acidified (pH = 4) with 2 M HCl. After the mixture was extracted with ethyl acetate, the organic layer was washed with water and brine, and dried over anhydrous Na 2 SO 4 . Concentration of the organic solution gave the title compound (yield 94%). Single crystals suitable for X-ray diffraction were obtained by slow evaporation of an acetone/n-hexane solution of the compound at room temperature.

Refinement
The hydrogen atoms of phenyl groups were placed in geometrical positions [C-H 0.95 Å, U iso (H) = 1.2U eq (C)], and refined using a riding model. Hydrogen atoms of methyl group were found in a difference Fourier map, and a rotating group model was applied with distance constraint [C-H = 0.98 Å, U iso (H) = 1.2U eq (C)]. The carbamoyl and carboxyl groups were disordered, and the occupancies of carbamoyl and carboxyl groups were determined to 0.558 (15)    The molecular structure of the title compound, with displacement ellipsoids drawn at the 50% probability level.
Hydrogen atoms are shown as small spheres of arbitrary radius. Disordered atoms are discriminated with A/B notation, and the minor disordered form B is drawn as dashed bonds.
Special details Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F 2 . R-factor (gt) are based on F. The threshold expression of F 2 > 2.0 σ(F 2 ) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (