4-Hydroxy-1-methyl-3-phenylquinolin-2(1H)-one

In the title compound, C16H13NO2, the quinoline system is approximately planar with a maximum deviation from the least-squares plane of 0.059 (1) Å for the N atom. The phenyl ring is rotated by 62.16 (4)° with respect to the plane of the quinoline system. In the crystal, O—H⋯O hydrogen bonds link molecules into infinite chains running along the b-axis direction.

In the title compound, C 16 H 13 NO 2 , the quinoline system is approximately planar with a maximum deviation from the least-squares plane of 0.059 (1) Å for the N atom. The phenyl ring is rotated by 62.16 (4) with respect to the plane of the quinoline system. In the crystal, O-HÁ Á ÁO hydrogen bonds link molecules into infinite chains running along the b-axis direction.   Table 1 Hydrogen-bond geometry (Å , ). This study was supported by the internal grant of the TBU in Zlin (No. IGA/FT/2012/043) funded from the resources of specific university research and the Slovenian Research Agency (Project P1-0230-0103 and Joint Project BI-CZ/07-08-018). This work was also partly supported through the infrastructure of the EN-FIST Centre of Excellence, Ljubljana. to the preparation of compound I and other 4-hydroxyquinoline-2-diones, intramolecular condensations of 2-acylaminobenzoates could be particularly feasible (Martensson & Nilsson, 1960;Bezuglyi et al., 1992). Recently, compound I was utilized for the preparation of the corresponding 3-bromo-and 3-chloro-1-methyl-3-phenylquinoline-2,4(1H,3H)-diones, from which other compounds were prepared by nucleophilic substitution of the halogen atom (Kafka et al., 2002;Klásek et al., 2002).

Related literature
In the crystal structure of the title compound (I) (Fig. 2) 4-hydroxy-1-methyl-3-phenylquinolin-2(1H)-one molecules are connected by intermolecular O-H···O hydrogen bonds between the hydroxyl and carbonyl groups (Table 1). These connections form linear chains along the b-axis in the crystal structure.

Experimental
Title compound was prepared according to a modified procedure published by Baumgarten & Kärgel (1927). A mixture of N-methylaniline (10.7 g, 100 mmol) and diethyl phenylmalonate (24.8 g, 105 mmol) was gradually heated in a Wood's metal bath at 200-290 °C for 4.5 h (until the distillation of ethanol stopped; reached 8.57 g, i.e. 93% of theoretical mass of distillate). The hot reaction mixture was poured into a mortar, crushed after cooling and dissolved in the mixture of aqueous sodium hydroxide solution (0.5 M, 300 ml) and toluene (50 ml). The aqueous phase was separated, washed with toluene, shortly stirred with active carbon, filtered and acidified by addition of 10% hydrochloric acid to Kongo red. The precipitated white solid was filtered off, washed with water and air dried affording 23.4 g (93% of theory) of crude product, m. p. 223-225 C. Crystallization of the crude product from ethanol afforded 20.1 g (80% of theoretical yield) of the title compound (I), m. p. 222-226 °C. In the literature (Martensson & Nilsson, 1960), the same m. p. is given.

Refinement
All H atoms were included in the model at geometrically calculated positions and refined using a riding model, with C-H bond lengths constrained to 0.93 Å (aromatic CH), 0.96 Å (methyl CH 3 ), and O-H = 0.82 Å, and with U iso (H) values of 1.2U eq (C) [for aromatic CH] or 1.5U eq (C) [for OH and methyl groups]. In the absence of significant anomalous scattering, the Flack parameter could not be determined reliably. Therefore Friedel-pairs were merged prior to the final refinement cycle. 16 low angle reflections were dropped by the integration routines because of detector saturation.   The packing of (I), with the O-H···O hydrogen bonds. [Symmetry code: (i) -x, y + 1/2, -z + 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 > 2σ(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.

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