Crystal structure of 4-methyl-N-[2-(piperidin-1-yl)ethyl]benzamide monohydrate

In the title compound, C15H22N2O·H2O, the dihedral angle between the planes of the piperidine and benzene rings is 31.63 (1)°. The piperidine ring adopts a chair conformation. The water solvent molecule is involved in interspecies O—H⋯O, O—H⋯N, N—H⋯O and weak C—H⋯O hydrogen-bonding interactions, giving rise to chains extending along [010].


S1. Comment
Biologically active alkaloids of substituted piperidines have been targeted for their total or partial synthesis (Ramalingan et al., 2004). Piperidines are known to have CNS depressant action at low dosage levels and stimulant activity with increased doses. In addition, the nucleus also possesses analgesic, anglionic blocking and anesthetic properties as well (Sergeant & May, 1970). Benzamides have been reported to correlate with many pharmacological processes such as antiemetic, anti-psychotic and anti-arrythmic activities. Various N-substituted derivatives of benzamide are reported to possess anti-convulsant activity (Magar et al., 2010;Fun et al., 2011 The substituted benzamide derivative, the title compound, C 15 H 24 N 2 O 2 , has been prepared and the structure is reported herein. In this compound ( Fig. 1) the dihedral angle between piperidine ring the and the benzene ring ring is 31.63 (1)°. The water molecule is involved in the formation of inter-species hydrogen-bonding interactions (Table 1), acting as both a double donor (O1W-H···O i and O1W-H···N1 ii ) as well as an acceptor (N2-H···O1W. One-dimensional chains are generated, extending along [010] (Fig. 2). Weak C-H···OW hydrogen bonds are also present.

S2. Experimental
The title compound was synthesized following a published procedure (Prathebha et al., 2014(Prathebha et al., , 2015. In a 250 ml roundbottomed flask, 120 ml of ethylmethylketone was added to 1,2-aminoethylpiperidine (0.02 mol) and stirred at room temperature. After 5 min, triethylamine (0.04 mol) was added and the mixture was stirred for 15 min. 4-Methylbenzoyl chloride (0.04 mol) was then added and the reaction mixture was stirred at room temperature for 2 hr. A white precipitate of triethylammonium chloride was formed, which was filtered and the filtrate was evaporated to give the crude product.
Two recrystallizations from ethylmethylketone give colourless block-like crystals of the title compound (yield: 82%).

S3. Refinement
Hydrogen atoms were positioned geometrically and treated as riding on their parent atoms and water H-atoms were and an N-H distance of 0.86 Å, with U iso (H) = 1.5 U eq (C-methyl), 1.5U eq (O) and 1.2U eq (C) for other H atoms. One reflection (100) was considered to be affected by the beamstop.

Figure 1
The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level.

Figure 2
The packing of the molecules in the crystal structure. The dashed lines indicate hydrogen bonds.

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.