(Z)-Ethyl 2-cyano-3-(1H-imidazol-2-yl)acrylate

The crystal structure of the title compound, C9H9N3O2, features N—H⋯N and C—H⋯O interactions. The N—H⋯N interaction generates a chain running along the a axis and the C—H⋯O interaction generates a chain along the c axis. An intramolecular C—H⋯O interaction is also observed.

The crystal structure of the title compound, C 9 H 9 N 3 O 2 , features N-HÁ Á ÁN and C-HÁ Á ÁO interactions. The N-HÁ Á ÁN interaction generates a chain running along the a axis and the C-HÁ Á ÁO interaction generates a chain along the c axis. An intramolecular C-HÁ Á ÁO interaction is also observed.
Experimental Crystal data C 9 H 9 N 3 O 2 M r = 191.19 Orthorhombic, Pca2 1 a = 10.0768 (7) Table 1 Hydrogen-bond geometry (Å , ). Data collection: SMART (Bruker 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97. The Knoevenagel condensation is an important carbon-carbon bond-forming reaction in organic synthesis (Knoevenagel, 1898;Yadav et al., 2004). This reaction has been widely used in organic synthesis to prepare many biologically active derivatives, and in the synthesis of cosmetics, perfumes and pharmaceuticals (Bigi et al., 1999;Yu et al., 2000). With the view of biological importance, the series of compounds are synthesized and here we report the crystal structure of the title compound.
Atoms C6, C9, N3 and O1 deviate from the planarity of the title compound with maximum deviation of 0.31 (3) Å by O1 atom. The crystal structure is stabilized by C(4)-H(4)···O1 intramolecuar interaction generating S(5) motif. The crystal packing is stabilized by N-H···N and C-H···O intermolecular interaction network. Atom N1 acts as a donor to N2 generating chain of C(4) along a axis and atom C1 acts as a donor to O1 generating C(8) chain running along c axis.

Experimental
A solution of 1H-Imidazole-2-aldehyde (1 mol), ethyl cyanoacetate (1.2 mol) and piperidine (0.1 ml) in ethanol (20 ml) was stirred at room temperature for 4 h. After removal of the volatiles in vacuo, yellow solid was obtained in quantitative yield. A sample for analysis was obtained by recrystallization from EtOAc as pale yellow needles.

Refinement
Friedel pairs were merged in the absence of any anamalous scatterers in the molecule. The absolute structure in the present model has been chosen arbitrarily. All H-atoms were refined using a riding model with d(C-H) = 0.93 Å, U iso = 1.2U eq (C) for aromatic, 0.97 Å, U iso = 1.2U eq (C) for CH 2 and 0.96 Å, U iso = 1.5U eq (C) for CH 3 atoms

Figure 2
The molecular packing of (I). For clarity, hydrogen atoms which are not involved in hydrogen bonding are omitted. 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq