(E)-1-(1,3-Benzodioxol-5-yl)-4,4-dimethylpent-1-en-3-one

In the molecule of the title compound, C14H16O3, all non-H atoms except for one methyl C atom lie on a crystallographic mirror plane. The conformation with respect to the C=C bond [1.3465 (12) Å] is trans. In the crystal, molecules are linked via C—H⋯O hydrogen bonds into C(5) chains propagating along [100].

In the molecule of the title compound, C 14 H 16 O 3 , all non-H atoms except for one methyl C atom lie on a crystallographic mirror plane. The conformation with respect to the C C bond [1.3465 (12) Å ] is trans. In the crystal, molecules are linked via C-HÁ Á ÁO hydrogen bonds into C(5) chains propagating along [100].

Al-Deeb Comment
Epilepsy is a group of serious disorders of the brain characterized by excessive temporary neuronal discharge resulting in recurrent unprovoked seizures (Pessah et al., 2009). It affects approximately 1% of mankind and the majority of cases are in the developing countries (Jain, 2005;Medina et al., 2005). It affects about 50 million people worldwide, 1 person in 50 will develop epilepsy at some time in his life and 1 in 20 will have a single epileptic seizure. Despite the development of new methods of seizure control, chronic administration of antiepileptic drugs (AEDs) remains the treatment of choice.
However, the number of non-responding patients is as high as 30% and chronic medication with currently available AEDs may result in severe side-effects and undesired drug interactions. That is why in recent years intensive research has been carried out aiming at the development of new therapeutic strategies in epilepsy. The title compound is the precursor of the recently marketed antiepileptic drug, Stiripentol. Reduction of the title compound will give Stiripentol.

Experimental
A 50% aqueous solution of KOH (78.5 ml) was added to a stirred solution of piperonal (11.0 g, 0.074 mol) and pinacolone (10.2 ml, 7.4 g, 0.074 mol) in methanol (200 ml). The reaction mixture was stirred and heated at 343 K for 5 h. The reaction mixture was cooled to room temperature and diluted with water (150 ml). The precipitated solid was filtered off, washed with water (50 ml) and air dried to afford the title compound which was recrystallized from ethanol as colourless blocks, m.p. = 366 K (Aboul-Enein et al., 2011).

Refinement
All H atoms were located in a difference Fourier map and refined freely with C-H = 0.952 (17)-1.026 (16) Å.

Computing details
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009 (Cosier & Glazer, 1986) operating at 100.0 (1) K. 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.