Crystal structure of methyl 2-[5-(2-hydroxyphenyl)-2H-tetrazol-2-yl]acetate

The title compound, methyl 2-[5-(2-hydroxyphenyl)-2H-tetrazol-2-yl]acetate, is the major product from the reaction between 2-(2H-tetrazol-5-yl)phenol and methyl 2-bromoacetate in the presence of potassium carbonate, which gave three isomeric products.


Chemical context
Tetrazole ligands are useful building blocks for the construction of high-dimensional metal-organic frameworks by providing various binding modes toward metal centers (Karaghiosoff et al., 2009;Liu et al., 2013). Recently, we have used 5-(2-hydroxyphenyl)tetrazole as a chelating multidentate ligand and reported several interesting compounds (Park et al., 2015;2014). It provides strong [N,O] chelation to metal centers with various additional binding modes. As part of a project on the study of the substitution effects on the tetrazole ring on the self-assembly behaviour in solution, as well as in the solid state, we have synthesized a number of substituted hydroxyphenyl tetrazole complexes. The substitution of the tetrazole group may promote supramolecular interaction by weak interactions, such as hydrogen bonding. The reaction between hydroxyphenyl tetrazole and bromo acetate methyl ester in the presence of potassium carbonate gave three isomeric products. Using column chromatography, the major product was isolated and its molecular structure was determined unambiguously by X-ray crystallography. We report herein, the synthesis and crystal structure of this compound.

Structural commentary
The molecular structure of the title compound is shown in Fig. 1. The structure analysis confirms the nature of the major product of the reaction, which yielded three isomeric compounds as described in Section 5, Synthesis and crystallization. The title molecule consists of a tetrazole ring (N1-N4/ C1) and a phenol ring (C2-C7), which are connected by an intramolecular O-HÁ Á ÁN hydrogen bond (Fig. 1

Synthesis and crystallization
The synthesis of the title compound is illustrated in Fig. 3. 2-(2H-Tetrazol-5-yl)phenol (100 mg, 0.62 mmol) and potassium carbonate (85.0 mg, 0.62 mmol) were dissolved in acetonitrile at 273 K while stirring for 30 min. To the resulting solution methyl 2-bromoacetate (207 ml, 2.18 mmol) was added and stirring was continued for 24 h. The white solid that was obtained was filtered and the solvent removed under reduced pressure. The residue was purified by column chromatography on silica gel using ether:hexane (2:3) as eluent. Three isomeric compounds were obtained, as shown in Fig. 3. The major product (I) (yield = 59%), was recrystallized in dichloromethane and yielded needle-like colourless crystals of the title compound.  Table 1 Hydrogen-bond geometry (Å , ). Symmetry code: (i) Àx þ 1; Ày; Àz þ 1.

Figure 2
A view along the a axis of the crystal packing of the title compound. The intra-and intermolecular hydrogen bonds (see Table 1) are indicated by dashed lines. The offsetinteractions are shown as dashed double arrows. Only H atoms H1 and H5, and the major component of the disordered OH group in position 2, have been included.

Figure 1
A view of the molecular structure of the title compound, with the atom labelling and 30% probability displacement ellipsoids. The intramolecular O-HÁ Á ÁN hydrogen bond (see Table 1

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. The hydroxy group is disordered about positions 2 and 6 on the phenol ring, with a refined occupancy ratio of 0.531 (5):0.469 (5). All the H atoms were included in calculated positions using a riding model: O-H = 0.84 Å , C-H = 0.95-1.00 Å with U iso (H) = 1.5 U eq (O-hydroxyl, C-methyl) and 1.2U eq (C) for other H atoms.  program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

sup-2
Acta Cryst. (2017). E73, 1971-1973 Special details 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (