8-Chloromethyl-5-(2,5-dioxooxolan-3-yl)-3,3a,4,5-tetrahydro-1H-naphtho[1,2-c]furan-1,3-dione

The title compound, C17H13ClO6, is an asymmetric alicyclic dianhydride containing a chloromethyl-substituted tetrahydronaphthalene moiety. The cyclohexene ring in the tetrahydronaphthalene moiety exhibits an envelope conformation with the tertiary C atom as the flap The dihedral angle between the two anhydride rings is 79.96 (6)°, while those between the benzene ring and the non-fused and fused anhydride rings are 71.03 (5) and 42.57 (7)°, respectively. In the crystal, molecules are connected by weak C—H⋯O interactions, forming a three-dimensional supramolecular structure.

The title compound, C 17 H 13 ClO 6 , is an asymmetric alicyclic dianhydride containing a chloromethyl-substituted tetrahydronaphthalene moiety. The cyclohexene ring in the tetrahydronaphthalene moiety exhibits an envelope conformation with the tertiary C atom as the flap The dihedral angle between the two anhydride rings is 79.96 (6) , while those between the benzene ring and the non-fused and fused anhydride rings are 71.03 (5) and 42.57 (7) , respectively. In the crystal, molecules are connected by weak C-HÁ Á ÁO interactions, forming a three-dimensional supramolecular structure.   Table 1 Hydrogen-bond geometry (Å , ). to ultraviolet lights of high-pressure mercury lamps have been successfully developed via the reaction of chloromethyl substituted in the PI molecules with photosensitive substances, such as cinnamic acid (Zhang et al., 2003). In addition, chloromethyl-containing PIs exhibited good sensitivity to linearly polarized ultraviolet light, which making it possible using the PIs for the photoalignment fabrication of liquid crystal molecules in advanced liquid crystal display devices (Zhong et al., 2004). In the current work, we reported a novel chloromethyl-containing alicyclic dianhydride monomer.

Experimental
Into a 500 ml three-necked flask equipped with a mechanical stirrer, a nitric oxide inlet, and a condenser, 43.75 g(0.446 mol) of maleic anhydride, 104.09 g(0.682 mol) of 4-chloromethylstyrene, 0.1138 g(0.5 mmol) of 2,5-di-tert-butyl hydroquinone were added. The reaction mixture was heated to 120°C and maintained for 6 h under nitric oxide. The produced red-brown nitrogen oxide gas was trapped by passing through an aqueous solution of 20 wt% sodium hydroxide. White needle crystals were formed. After the reaction was completed, 60 ml of acetonitrile was added and the solution was refluxed for about 0.5 h. Then 60 ml of toluene was added and the reactino mixture was cooled to room temperature. The produced white needle crystals was collected by filtration and the solid was washed with toluene and petroleum ether in succession. After being dried in vacuum, the pure MCTDA was obtained as white crystals. Yield: 59.49 g(76.5%).

Refinement
All H atoms were positioned geometrically (C-H=0.95-1.00 Å) and refined using a riding model with the U iso (H)=1.2 U eq C for both of the aromatic ring and aliphatic chain.

Figure 1
The molecular structure of the title compound, showing diaplacement ellipsoids at the 30% probability level. 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 Cl1 1.05131 (7