N-[2-(4-Methylbenzoyl)ethyl]propan-2-aminium chloride

In the title compound, C13H20NO+·Cl−, the protonated amino N atom is hydrogen bonded to the chloride anion. N—H⋯Cl hydrogen bonds link the anions and cations into dimers, which are connected by C—H⋯O hydrogen bonds, forming supramolecular chains extending along [100].


Experimental
Crystal data C 13 H 20 NO + ÁCl À M r = 241.75 Monoclinic, P2 1 =c a = 7.786 (5) Å b = 7.511 (5) Å c = 23.365 (5) Table 1 Hydrogen-bond geometry (Å , ). Mannich bases are generally formed by the reaction between formaldehyde, a secondary amine and a compound containing reactive hydrogen atoms. On occasion, aldehydes other than formaldehyde may be employed and the secondary amine may be replaced by ammonia and primary amines. This process is known as the Mannich reaction (Dimmock & Kumar, 1997).
In the title compound (I), (Fig. 1), bond lengths and bond angles are within the range of expected values for this type of compound (Allen et al., 1987;Abonia et al., 2011;Tuzina et al., 2006). The protonated N1 atom forms a hydrogen bond to Cl1 (Table 1). Intra-and intermolecular N-H···Cl hydrogen-bonding interactions between the free chloride anion and the organic cation link the molecules into hydrogen-bond dimers, forming a R 2 2 (6) motif (Bernstein et al., 1995;Etter, 1990). The dimers are connected by C-H···O hydrogen bonds into chains extended along the a axis (Table 1, Fig. 2).

Experimental
A mixture of the appropriate ketone (50 mmol), paraformaldehyde (50 mmol), and isopropylamine hydrochloride (27 mmol) was heated in an oil bath at 403 K. The reaction vessel was then removed from the oil bath and when the temperature of the mixture dropped to 338 K, ethyl acetate (40-80 ml) was added. The mixture was stirred at room temperature for 24 h and the resultant precipitate was then collected and were recrystallized from ether/methanol. The melting point and yield of this compound was: 443-444 K (lit. Plastino et al., 1964 m.p. 444-445 K), 58% (Mete et al., 2011b).

Figure 1
The title molecule with the atom numbering scheme. Displacement ellipsoids fornon-H atoms are drawn at the 30% probability level.

Figure 2
The packing and hydrogen bonding of the title compound viewed down the baxis. H atoms not involved in hydrogen bondings are omitted for clarity.

Special details
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.