1-(1,3-Benzodioxol-5-yl)pentan-1-one

In the molecule of title compound, C12H14O3, the benzodioxole ring system is essentially planar. In the crystal structure, weak intermolecular C—H⋯O hydrogen bonds link molecules into chains along the c axis, and π–π contacts between dioxole rings and between dioxole and benzene rings of the benzodioxole ring systems [centroid–centroid distances 3.702 (3) and 3.903 (3) Å] may further stabilize the structure. Two C—H⋯π interactions are also found.

In the molecule of title compound, C 12 H 14 O 3 , the benzodioxole ring system is essentially planar. In the crystal structure, weak intermolecular C-HÁ Á ÁO hydrogen bonds link molecules into chains along the c axis, andcontacts between dioxole rings and between dioxole and benzene rings of the benzodioxole ring systems [centroid-centroid distances 3.702 (3) and 3.903 (3) Å ] may further stabilize the structure. Two C-HÁ Á Á interactions are also found.

Comment
The title compound is an important medicine intermediate used to synthesize methylenedioxypyrovalerone (Koeppe et al., 1969). As part of our studies in this area, we report herein its crystal structure.
In the crystal structure, weak intermolecular C-H···O hydrogen bonds (Table 1) link the molecules into chains along the c axis ( Fig. 2), in which they may be effective in the stabilization of the structure. The π-π contacts between the dioxole rings and the dioxole and benzene rings of the benzodioxole ring systems, Cg1-Cg1 i and Cg1-Cg2 i [symmetry code: (i) 1 -x, 1 -y, -z where Cg1 and Cg2 are centroids of the rings A (O2/O3/C9/C10/C12) and B (C6-C11), respectively] may further stabilize the structure, with centroid-centroid distances of 3.702 (3) Å and 3.903 (3) Å. There also exist two C-H···π interactions (Table 1).

Experimental
The title compound was synthesized according to a literature method (May et al., 2000). Crystals suitable for X-ray analysis were obtained by dissolving the title compound (0.2 g) in methanol (25 ml), and evaporating the solvent slowly at room temperature for about 7 d.

Refinement
H atoms were positioned geometrically, with C-H = 0.93, 0.97 and 0.96 Å for aromatic, methylene and methyl H, respectively, and constrained to ride on their parent atoms with U iso (H) = xU eq (C), where x = 1.5 for methyl H and x = 1.2 for all other H atoms.