Dimethyl 2-nitroterephthalate

In the molecule of the title compound, C10H9NO6, the two ester groups and the nitro group are inclined at 9.2 (2), 123.3 (6) and 135.2 (5)°, respectively to the mean plane of the benzene ring. In the crystal structure, molecules are stacked along the a axis, without any π–π interactions. The stacked columns are linked together by non-classical intermolecular interactions of the type C—H⋯O.

In the molecule of the title compound, C 10 H 9 NO 6 , the two ester groups and the nitro group are inclined at 9.2 (2), 123.3 (6) and 135.2 (5) , respectively to the mean plane of the benzene ring. In the crystal structure, molecules are stacked along the a axis, without anyinteractions. The stacked columns are linked together by non-classical intermolecular interactions of the type C-HÁ Á ÁO

S1. Comment
The title compound, (I), is useful as a raw material for the preparation of 2-amino-dimethyl-terephthalic acid, which is used as an important intermediate for dyes (Niu et al., 2002). The structures of dimethyl terephthalate (Brisse & Pérez, 1976) and dimethyl 2,3-dihydroxyterephthalate (Huang & Liang, 2007) which are closely related to the title compound have already been reported. In this article, we report the crystal structure of (I). A view of the molecule of (I) is presented in Fig. 1. The bond lengths and angles are within expected ranges. The C1/O1/C2/O2, C10/O6/C9/O5 and O3/N/O4 planes form dihedral angles of 9.2 (2), 123.3 (6) and 135.2 (5)°, respectively, with the C3-C8 plane. In the crystal structure, the molecules are stacked along the a axis, without any π-π interactions. The stacked columns are linked together by non-classical intermolecular interactions of the type C-H···O (Table 1).

S2. Experimental
A sample of commercial 2-nitro-dimethyl-terephthalic acid (Aldrich) was crystalized by slow evaporation of a solution in methanol.

S3. Refinement
Positional parameters of all the H atoms bonded to C atoms were calculated geometrically and were allowed to ride on the C atoms to which they are bonded, with H-C(aryl) = 0.93 Å and U iso (H) = 1.2U eq (C) or with H-C(methyl) = 0.96 Å and U iso (H) = 1.5U eq (C).  A view of the molecule of (I) with the atomic numbering scheme. Displacement ellipsoids were drawn at the 30% probability level.

Dimethyl 2-nitroterephthalate
Crystal data C 10 H 9 NO 6 M r = 239.18 Monoclinic, P2 1 /n Hall symbol: -P 2yn a = 6.9080 (14)  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.