Dimethyl 2,2′-(p-phenylenedioxy)diacetate

The title compound, C12H14O6, was prepared by the Williamson reaction of 1,4-dihydroxybenzene and methyl chloroacetate with phase-transfer catalysis. The compound lies on an inversion center. The structure is stabilized by weak C—H⋯π interactions.

The title compound, C 12 H 14 O 6 , was prepared by the Williamson reaction of 1,4-dihydroxybenzene and methyl chloroacetate with phase-transfer catalysis. The compound lies on an inversion center. The structure is stabilized by weak C-HÁ Á Á interactions.

Comment
The derivatives of aryloxyacetic acids and their derivatives constitute a class of compounds for both biological activity and plant growth regulators (Nagy et al., 1997;Wei et al.,2005). The phase-transfer catalysis, with the advantages of simple experimental operations, mild reaction conditions, and inexpensive and environmentally benign reagents, has established its significance in organic synthesis as one of the most useful methods for the acceleration of heterogeneous reactions (Perreux & Loupy, 2001).
Benzothiazole are remarkable heterocyclic ring systems. They have been found to exhibit a wide spectrum of biological activities. Many kinds of 2-substituted benzothiazoles are utilized as vulcanization accelators in the manufacture of rubber,as fluorescent brightening agents in textile dyeing,and in the leather industry (Chakraborti et al.,2004;Seijas et al.,2007;Wang et al.,2009). There are numerous synthetic methods to produce 2-arylbenzothiazoles. The most important ones include the reaction of o-aminothiophenols with benzoic acids or their derivatives (Chakraborti et al.,2004;Seijas et al.,2007;Wang et al.,2009). We are focusing on the synthesis of new products of bisbenzothiazole. We here report the crystal structure of the title compound (I).
The compound (I) lies on an inversion center (Fig.1). All bond lengths are within normal ranges (Allen et al., 1987).
Experimental 5.5 g (0.05 mole) hydroquinone was dissolved in 50 ml acetone, 6.9 g (0.05 mole) potassium carbonate, potassium iodide 0.8 g and tetrabutyl ammonium bromide 1.0 g were added. Then 8.8 ml L (0.10 mole) of methyl chloroacetate was dropped into the mixture. The mixture was boiled for 5 h with intensive stirring, cooled to room temperature, and filtered. The organic solution was evaporated under vacuum to dryness and the dry residue was recrystallized from methanol to obtain title compound. Crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of ethyl acetate. 1 H NMR (CDCl 3 , δ, p.p.m.) 6.85 (m, 4H), 4.58 (s, 4H), 3.79 (s,6H).

Refinement
All H atoms were positioned geometrically and treated as riding on their parent C atoms with C-H = 0.93 Å (aromatic), 0.97Å (methylene) and 0.96Å (methyl) with U iso (H) = xU eq (C), where x= 1.5 for methyl H and 1.2 for aromatic and methylene H atoms.