(RS)-1-[5-(2-Chloropropyl)indolin-1-yl]ethanone

In the title compound, C13H16ClNO, the acetylindoline moiety is roughly planar (r.m.s. deviation = 0.0048 Å). The chloropropyl group is out of the plane and is statistically disordered over two positions. Indeed, the Cl and CH3 groups located on the stereogenic carbon exchange with each other. The whole crystal is a racemate. Non-classical C—H⋯O hydrogen bonds between symmetry-related benzene rings stabilize the crystal structure.


Experimental
In searching for new synthetic route of silodosin, a adrenoceptor antagonist (Sorbera et al. 2001;Elworthy et al. 1997;Asselin et al. 2000;Bremner et al. 2000), we synthesized the title compound as racemic intermediate.
In the title compound, C 13 H 16 ClNO, the acetylindoline moiety is mainly planar with the largest deviation from the plane being 0.0076 (14)Å at C2. The chloropropane being out of the plane with the C12 atom located 1.0254 (0.0028)Å above the plane (Fig. 1). The chloropropane moiety is statistically disordered over two positions. Indeed, the Cl and CH 3 located on the stereogenic carbon exchange each other. The geometry within the 1-acetylindoline fragment compares well with related structures as 1-acetylindoline (Moreno et al., 1998) or 1-(trifluoro)acetylindoline (Wang et al., 2007).
The Cl and CH3 substituents on the stereogenic carbon are exchanging each other and such disorder induces two configurations. Two sets of positions were defined for the atoms of this group and the site occupation factor of each conformation were refined while restraining their sum to unity and using restraints on C-C and C-Cl distances with the help of SAME and PART instructions within SHELXL97 (Sheldrick, 2008). In the last stage of refinement, the disordered Cl and C atoms were anisotropically refined but the anistropic thermal parameters of the C atoms were restrained to have similar atomic displacement parameters within a tolerance s.u. of 0.01 Å 2 .

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 > σ(F 2 ) is used only for calculating Rfactors(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 Occ. (