[1,5-bis(1-methyl-1H-tetrazol-5-yl-kappaN)-3-oxopentane-kappaO]dichlorocopper(II).

The title compound, [CuCl2(C8H14N8O)], is the first structurally characterized molecular chelate complex of a binuclear N-substituted tetrazole. The Cu atom is five-coordinate, with an approximately square-pyramidal geometry. The equatorial positions of the pyramid are occupied by two Cl atoms and two N atoms from the ligand molecule; the O atom of the ligand lies in the axial position. Each complex is connected to four others via weak C-H...Cl and C-H...N interactions, forming sheets parallel to the (010) plane.

2-(1H-tetrazol-1-yl)benzoic acid.

In the title compound, C8H6N4O2, the tetrazole and benzene rings are planar to within 0.001 (1) and 0.007 (1) A, respectively. These rings are not coplanar in the molecule, the dihedral angle between them being 52.90 (4) degrees. Molecules are connected together by O-H...N and C-H...O hydrogen bonds, forming two-dimensional networks parallel to the xz plane with van der Waals interactions between them.

4-Nitro-2-(1H-tetrazol-1-yl)phenol.

There are two symmetry-independent molecules in the unit cell of the title compound, C(7)H(5)N(5)O(3). The tetrazole and phenyl rings are essentially planar and are not coplanar in either molecule [dihedral angles 30.2 (1) and 7.0 (1) degrees]. In the structure, four molecules are connected by O-H...N bridges, forming four-membered molecular aggregates which are linked together by a complex three-dimensional hydrogen-bond network.

Synthesis of C-5'-alkyl substituted 17-spirofuran 19-norsteroids.

A number of new steroidal 17-spirofuran derivatives of the 19-nor series containing Me, Et or (i)Pr-substituents in the heterocyclic moiety has been prepared, which are expected to have a strong progestagenic activity. The proposed approach made use of the 1-3-dipolar cycloaddition of low-molecular nitrile oxides with steroidal acetylenic alcohols followed by transformation of the isoxazole side chain.