N-(2-Chloroethyl)morpholine-4-carboxamide

The title compound, C7H13ClN2O2, synthesized by the reaction of 2-chloroethyl isocyanate and morpholine, crystallizes with four molecules in the asymmetric unit, which have similar conformations and comprise two pairs each related by approximate non-crystallographic inversion centres. Two of them have a modest orientational disorder of the 2-chloroethyl fragments [occupancy ratio of 0.778 (4):0.222 (4)]. In the crystal, molecules are linked by N—H⋯O=C hydrogen bonds, forming three crystallographically different kinds of infinite hydrogen-bonded chains extending along [001].

The title compound, C 7 H 13 ClN 2 O 2 , synthesized by the reaction of 2-chloroethyl isocyanate and morpholine, crystallizes with four molecules in the asymmetric unit, which have similar conformations and comprise two pairs each related by approximate non-crystallographic inversion centres. Two of them have a modest orientational disorder of the 2-chloroethyl fragments [occupancy ratio of 0.778 (4):0.222 (4)]. In the crystal, molecules are linked by N-HÁ Á ÁO C hydrogen bonds, forming three crystallographically different kinds of infinite hydrogen-bonded chains extending along [001].

Comment
The title compound, N-(2-chloroethyl) morpholine-4-carboxamide, was prepared as part of an ongoing project investigating the multifunctional alkylation of [Pt 2 (µ-S) 2 (PPh 3 ) 4 ] (Ujam et al., 2010). The X-ray structure determination established the molecular structure and atom connectivity of the title compound C 7 H 13 Cl 1 N 2 O 2 ( Fig. 1). There are four independent molecules in the asymmetric unit which have the same overall conformation and comprise two pairs each related by approximate non-crystallographic inversion centres. Two of them have a modest orientation disorder of the 2chloroethyl fragments. The molecules consist of a chair-shaped morpholine ring attached to a planar urea-type N 2 CO unit.
The 2-chloroethyl side chains are oriented approximately perpendicular to the N 2 CO unit. In the crystal structure the molecules are linked by N-H···O═C hydrogen bonds (N···O = 2.809 (6) -2.831 (6) Å) to form three crystallographically different kinds of infinite hydrogen bonded chains extending along [001] (Fig. 2), all with criss-cross patterns of molecule orientations when viewed along the chains (Fig. 3).

Experimental
Morpholine [HN(CH 2 CH 2 ) 2 O, 200 mg, 0.002 mmol] was added to a solution of 2-chloroethyl isocyanate [ClCH 2 CH 2 NCO, 200 mg, 0.002 mmol] in diethyl ether (30 mL), immediately producing a white precipitate of the product. After stirring for 5 min the product was filtered and washed with ether (20 mL) and dried under vacuum to give ClCH 2 CH 2 NHC(O)N(CH 2 CH 2 ) 2 O. Crystals suitable for X-ray crystallographic analysis were obtained by vapour diffusion of diethyl ether into a dichloromethane solution.

Refinement
Crystal data, data collection and structure refinement details are summarized in the crystallographic data Table. Diffraction images of the reciprocal space calculated from the recorded frame data were consistent with the crystallography reported and did reveal neither commensurate nor incommensurate superstructure reflections. All attempts to solve the structure in space group C2/c were unsuccessful, but it solved readily in Cc. The compound has four independent molecules in the asymmetric unit, comprising two pairs each related by an apparent inversion centre at x,y,z = 0.43, 0.63, 0.81 for the molecules 1 (Cl1, O1, O2, N1, N2, C1 through C7) and 2 (Cl2, N3, N4, O3, O4, C8 through C14), and at x,y,z = 0.42, 0.88, 0.31 for molecules molecules 3 (Cl3, O5, O6, N5, N6, C15 through C21) and 4 (Cl4, N7, N8, O7, O8, C22 through C28) . The two inversion centres were approximately related by 0 0.25 0.5 which is not a crystallographic relationship in C2/c, so the structure could not be converted to the centrosymmetric cell. Refinement was completed in the non-centrosymmetric space group Cc, and the crystal treated as a racemic twin. Unrestrained refinement led to a large spread in values for chemically equivalent bond parameters, and some unrealistic thermal ellipsoids, no doubt arising from instability associated with the pseudosymmetry. Hence the final refinement restrained the independent supplementary materials sup-2 Acta Cryst. (2014). E70, o463 molecules to similar geometry using the SAME command of SHELXL, and EADP constraints were applied to equivalent atoms related by pseudosymmetry. Some residual electron density appeared to arise from partial disorder of the ethylene groups of two of the molecules (molecules 2 and 4) over two sites (0.78:0.22), so the C atoms of the minor component were included with fixed isotropic thermal parameters. Otherwise all non-hydrogen atoms were treated anisotropically. H atoms attached to carbon atoms were included in calculated positions [U iso (H) = 1.2×U equ (C)], but those attached to the amide N atoms were refined with DFIX constraints and U iso (H) = 0.03 fixed.

Figure 1
The molecular structure and atom numbering of one of the four independent molecules of the title compound with displacement parameters drawn at the 40% probability level for non-H atoms.

N-(2-Chloroethyl)morpholine-4-carboxamide
Crystal data   (17) 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. Refined as a 2-component inversion twin (here a polar twin) with a component ratio of 0.38/0.62. The final refinement restrained the four independent molecules to similar geometry using the SAME command of SHELXL, and EADP constraints were applied to equivalent atom pairs related by pseudosymmetry. Some residual electron density appeared to arise from partial disorder of the ethylene groups of two of the molecules over two sites (0.78:0.22) so the C atoms of the minor component were included with fixed isotropic thermal parameters.