N-Methyl-2-oxo-1-phenylpropan-1-aminium chloride

In the structure of the title compound, C10H14NO+·Cl−, both H atoms bound to nitrogen are involved in N—H⋯Cl hydrogen-bonding interactions. These interactions join the cations and anions into dimeric units (two cations and two anions) with R 4 2(8) motifs lying about inversion centers.

In the structure of the title compound, C 10 H 14 NO + ÁCl À , both H atoms bound to nitrogen are involved in N-HÁ Á ÁCl hydrogen-bonding interactions. These interactions join the cations and anions into dimeric units (two cations and two anions) with R 4 2 (8) motifs lying about inversion centers.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: YK2004).

Comment
The importance of molecular salts as solid forms in pharmaceutical formulations is well known. For a given active ingredient, the isolation and selection of a salt with the appropriate physicochemical properties involves significant screening activity and has been discussed at some length in the literature (Tong & Whitesell et al., 1998;Shanker et al., 1994). It is apparent that over 40% of marketed salts are hydrochlorides (Gould et al., 1986), and this trend is reflected in the available set of salt structures provided by the Cambridge Structural Database (Allen et al., 2002). Here we report the synthesis and crystal structure of the title compound, N-methyl-2-oxo-1-phenylpropan-1-aminium chloride (Fig. 1).
The bond distances and angles in the structure of the title compound agree very well with the corresponding distances and angles reported for a closely related compound (Au & Tafeenko et al., 1986). It is noteworthy that both H-atoms bonded to one nitrogen (N1) are involved in hydrogen bonding interactions of the type N-H···Cl hydrogen bonds, forming dimers lying about inversion centers according to R 2 2 (4) motifs in graph set notation (Tab.1, Fig.2). Dipole-dipole and van der Waals interactions are effective in the molecular packing.

Experimental
To a stirred solution of 1-(methylamino)-1-phenylpropan-2-one (2.445 g, 0.015 mol) in 30 mL of dry THF, hydrochloric acid (1.52 g, 0.015 mol) was added at the room temperature. The precipitate was filtered and washed with a small amount of ethanol 95%. Single crystals suitable for X-ray diffraction analysis were obtained from slow evaporation of a solution of the title compound in water at room temperature.

Refinement
The H-atoms bonded to the C-atom were positioned geometrically and refined using a riding model, with C-H = 0.93-0.97 Å and U iso (H) = 1.2U eq (C). The H-atoms bonded to the N-atom were located from a difference map and refined using a riding model. Fig. 1. View of the asymmetric unit of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.  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.