2-Benzyl-3-hydroxy-3-methyl-2,3-dihydro-1H-isoindol-1-one

In the title compound, C16H15NO2, the isoindoline ring system is approximately planar (mean deviation = 0.0186 Å) and makes a dihedral angle of 61.91 (4)° with the phenyl ring. In the crystal, molecules form inversion dimers via pairs of O—H⋯O hydrogen bonds.

In the title compound, C 16 H 15 NO 2 , the isoindoline ring system is approximately planar (mean deviation = 0.0186 Å ) and makes a dihedral angle of 61.91 (4) with the phenyl ring. In the crystal, molecules form inversion dimers via pairs of O-HÁ Á ÁO hydrogen bonds.
The molecular structure of the title compound is shown in Fig. 1 and there are some similiar stuctures reported before (Wang et al., 2008;Orzeszko et al., 1998;Liu et al., 2009;Rosamilia et al., 2002). In the molecule, the isoindol ring system is approximately planar [mean deviation = 0.0186 Å] and has a dihedral angle of 61.91 (4)° with the benzene ring.

ml me thyl magnesium bromide solution (3 M in ether) was added to a 25 ml round-bottom flask filled with nitrogen
and heated to 60 °C. A solution of N-benzylphthalimides (500 mg, 2.11 mmol) in toluene (15 ml) was added dropwise with stirring at a sufficient rate to maintain this temperature. When the addition was complete, the solution was heated to 110 °C and maintained at this temperature for 4 h. The reaction mixture was cooled to room temperature and petroleum was added. The mixture turned purple after stirring in air for 12 h. At the end, the mixture was filtered on celite and the filtrate obtained was dried, giving a precipitate which was separated by column chromatography on silica gel (eluent: ethyl acetate/petroleum ether, 1:3). The title compound was obtained as a colorless solid (123 mg, 23%) and evaporation of a solution in ethanol for 24 h afforded colorless single crystals suitable for X-ray diffraction.

Refinement
The hydroxy H atom was obtained by difference Fourier synthesis and refined freely. All other H atoms were placed at calculated positions, with C-H = 0.95-0.98 Å. The U iso (H) values were constrained to be 1.5Ueq(C) for the methyl H atoms or 1.2Ueq(C) for the aromatic H atoms.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. 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.