2-(3-Morpholinopropyl)-2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-one monohydrate

In the title compound, C18H21N3O2·H2O, the fused-ring system is approximately planar [maximum atomic deviation = 0.028 (3) Å]; the morpholine ring displays a chair conformation. The crystal packing is stabilized by classical intermolecular O—H⋯O and O—H⋯N hydrogen bonds and weak C—H⋯O hydrogen bonds between the organic molecules and the water molecules.


Comment
Quinoline analogues have been reported to display promising antibacterial (Vaitilingam et al., 2004), an-ticancer and antiplatelet (Lee et al., 2004), antiasthmatic (Zwaagstra et al., 1998), antiinflammatory (Roma et al., 2000, and antihypertensive activities (Ferrarini et al., 2000). We have synthesized some new quinoline derivatives (Yang et al., 2008). In continuation of our efforts to develop quinoline derivatives with a new structure-activity relationship, herein, we report the synthesis and structure determination the title compound.
The molecular geometry and the atom-labeling scheme of the title compound is illustrated in Fig. 1. The molecule contains three approximately coplanar rings and the dihedral angle between the three rings 1.60 (2)° and 1.20 (5)°, respectively; the C-N2-C-C torsion angles are 43.59° and -137.51°; the morpholine ring shows a stable chair conformation. The crystal structure can be depicted as layers along a-axis which ring systems are parallel to one another. The crystal packing is stabilized by intermolecular interactions between O and H atoms [C-H···O = 2.638Å].

Experimental
The precursor, ethyl 2-(bromomethyl)quinoline-3-carboxylate, was prepared according to the literature procedure (Yang et al., 2008;Zhou et al., 2010). The title compoud was synthesized by treating 1 mmol of ethyl 2-(bromomethyl)quinoline-3carboxylate with 1.2 mmol of 3-morpholinopropan-1-amine in the presence of NaHCO 3 in acetonitrile. The reaction was carried out under the stirring at room temperature for 10 h. Once the reaction was complete, the solid salt was filtered off and the filtrate was then concentrated under reduced pressure. The crude product was purified by silica gel column chromatography with the mixture of methanol and ethyl acetate (v /v = 1/20) to afford the white product. Crystals suitable for X-ray analysis were obtained by slow evaporation of the solution of petroleum ether and dichloromethane, in which the small amount of water was not removed.

Refinement
Water H atoms were located in a difference Fourier map and refined isotropically. Other H atoms were positioned geometrically and allowed to ride on their parent atoms, with C-H = 0.93-0.97 Å and U iso (H) = 1.2U eq (C).

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 > 2sigma(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.