organic compounds
The title compound, C8H4ClNO2Te, represents the first reported example of a benzofuran-derived 2,1,3-benzoxatellurazole derivative. While it can be formally described as a nitrosoaryltellurium monochloride, its Te-O and Te-C bond lengths of 2.1421 (14) and 2.0374 (17) Å, respectively, characterize it as a planar tricyclic aromatic containing a Te=C double bond. Its formation suggests that derivatives of 2-cyclohexenone oxime in general react with tellurium dioxide to form aryl-2,1,3-benzoxatellurazoles.
organic compounds
A second, monoclinic, polymorph of the title compound, C14H8Cl2, has been found. In addition to the structure of this monoclinic form, the structure of the previously described orthorhombic form [Desvergne, Chekpo & Bouas-Laurent (1978). J. Chem. Soc. Perkin Trans. 2, pp. 84–87; Benites, Maverick & Fronczek (1996). Acta Cryst. C52, 647–648] has been redetermined at low temperature and using modern methods. The low-temperature structure of the orthorhombic form is of significantly higher quality than the previously published structure and additional details can be derived. A comparison of the crystal packing of the two forms with a focus on weak intermolecular C—HCl interactions shows the monoclinic structure to have one such interaction linking the molecules into infinite ribbons, while two crystallographically independent C—HCl interactions give rise to an interesting infinite three-dimensional network in the orthorhombic crystal form.
pharmaceuticals and natural products
Glabridin is a species-specific biomarker from the roots Glycyrrhiza glabra L. (European licorice, Fabaceae). Stereochemical analysis, including circular dichroism, NMR data and an X-ray diffraction data set with Bijvoet differences, confirms that glabridin, purified from its natural source, is found only in a C3 R configuration.