Methyl 2-[(2-chloroquinolin-3-yl)(hydroxy)methyl]acrylate

There are two independent molecules (A and B) in the asymmetric unit of the title compound, C14H12ClNO3. The mean planes of the methyl ester unit (Cmethyl—O—C=O; r.m.s. deviation = 0.051 Å for molecule A and 0.016 Å for molecule B) and the chloroquilonine ring system (r.m.s. deviation = 0.023 Å for molecule A and 0.014 Å for molecule B) form dihedral angles of 63.5 (1)° in molecule A and 78.1 (1)° in molecule B. The main difference between the two independent molecules is reflected in the (H)O—C—C=C(H2) torsion angle which is −109.7 (2)° in molecule A and 10.6 (2)° in molecule B. An intramolecular O—H⋯O hydrogen bond is observed in molecule A. In the crystal, molecules A and B are linked into pairs via bifurcated O—H⋯(N,Cl) hydrogen bonds and a weak C—H⋯O hydrogen bond links pairs of molecules into chains along [100].

There are two independent molecules (A and B) in the asymmetric unit of the title compound, C 14 H 12 ClNO 3 . The mean planes of the methyl ester unit (C methyl -O-C O; r.m.s. deviation = 0.051 Å for molecule A and 0.016 Å for molecule B) and the chloroquilonine ring system (r.m.s. deviation = 0.023 Å for molecule A and 0.014 Å for molecule B) form dihedral angles of 63.5 (1) in molecule A and 78.1 (1) in molecule B. The main difference between the two independent molecules is reflected in the (H)O-C-C C(H 2 ) torsion angle which is À109.7 (2) in molecule A and 10.6 (2) in molecule B. An intramolecular O-HÁ Á ÁO hydrogen bond is observed in molecule A. In the crystal, molecules A and B are linked into pairs via bifurcated O-HÁ Á Á(N,Cl) hydrogen bonds and a weak C-HÁ Á ÁO hydrogen bond links pairs of molecules into chains along [100].
its crystal structure is presented herein.
The asymmetric unit of the title compound contains the two independent molecules, A and B (Fig. 1). The dihedral angle between the mean plane of methyl ester unit (C13/C14/O2/O3, r.m.s deviation = -0.051 Å for A and -0.016 Å for B) and the chloroquilonin ring system (C1-C9/N1/Cl1, r.m.s deviation = 0.023 Å for A and -0.014 Å for B) is 63.5 (1)° in molecule A and 78.6 (1)° in molecule B. The main difference between the two independent molecules is reflected in the O1-C10-C11-C12 torsion angle which is -109.7 (2)° in molecule A and 10.6 (2)° in molecule B.
The methyl ester moiety adopts an extended conformation as reflected by the torsion angles for C11-C13-C14-O3 = 177.7 (2)° in A and 178.4 (1)° in B. The extended conformation is supported by the fact that the bond angles involving the carbonyl O atoms are invariably expanded (Dunitz & Schweizer, 1982). The significant difference in the bond lengths of the C13-O3 = 1.322 (3) Å (A) 1.331 (3) Å (B) versus C14-O3 = 1.447 (3) Å (A) and 1.447 (2) Å (B) can be attributed to a partial contribution from the O --C═O + -C resonance structure of the O2-C13-O3-C14 group (Merlino, 1971). This feature, commonly observed in the carboxylic ester group of these substituents in various compounds has been shown to give average values of 1.340 Å and 1.447 Å respectively for these bonds (Varghese et al., 1986).
In the crystal molecule A and B are linked into pairs via bifurcated O-H···(N,Cl) hydrogen bonds (Fig. 2) and a weak C -H···O hydrogen bond links pairs of molecules into chains along [100].

Experimental
A mixture of 2-chloroquinoline-3-carbaldehyde (0.1 g, 0.52 mmol), methyl acrylate (0.071 ml, 0.78 mmol), and DABCO (0.017 g, 0.15 mmol), was kept at room temperature for 7 days. After completion of the reaction (indicated by TLC), the reaction mixture was extracted with ethylacetate (3 τimes 15 ml). The combined organic layer subsequently washed with dil.HCl and dried over anhydrous Na 2 SO 4 . The solvent was evaporated under reduced pressure. The crude product was obtained and purified by column chromatography eluting with 8% ethylacetate in hexane afforded the alcohol methyl 2-((2-chloroquinolin-3-yl)(hydroxy)methyl)acrylate as a colourless solid. X-ray quality crystals were obtained by slow evaporation of a solution of the title compound in ethylacetate.

Refinement
Hydrogen atoms were positioned geometrically and allowed to ride on their parent atoms, with C-H = 0.93-0.98 Å, O-H = 0.82° and U iso (H) = 1.5U eq (C) for methyl and hydroxyl H atoms and 1.2U eq (C) for other H atoms.

Figure 1
The asymmetric unit of the title compound showing 30% probability displacement ellipsoids. H atoms are shown as spheres of arbitrary radius.

Figure 2
Part of the crystal structure with hydrogen bonds shown as dashed lines.  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.29 e Å −3 Δρ min = −0.25 e Å −3 Extinction correction: SHELXL97 (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.0040 (11) 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.