3-Carbamoylquinoxalin-1-ium chloride

The title compound, C₉H₈N₃O⁺·Cl⁻, was isolated from a liquid culture of streptomyces sp. In the cation, the ring system makes a dihedral angle of 0.2 (2)° with the amide group. The protonation creating the cation occurs at ome of the N atoms in the quinoxaline ring system. In the crystal, the ions are linked through N—H...O and N—H...Cl hydrogen bonds, forming a two-dimensional network parallel to (10).

Bicyclo­[2.2.1]hept-2-en-7-yl 4-bromo­benzoate

The structure of the title compound, C₁₄H₁₃BrO₂, which contains a norbornenyl group and a 4-bromo­benzoate ester at the single C-atom bridge, has been redetermined [see McDonald & Trotter (1965). Acta Cryst. 19, 456-463] to modern standards to establish high-precision geometrical data to compare with norbornyl and other tetra­cyclic 4-bromo­benzoates. Possible structural evidence is sought to help explain solvolytic reactivities.

Bicyclo­[2.2.1]hept-7-yl p-bromo­benzoate

The title compound, C₁₄H₁₅BrO₂, contains a sterically unencumbered norbornyl group. The dihedral angle between the plane of the carboxyl­ate group and the mean plane of the adjacent benzene ring is 5.3 (2)°. The dihedral angle between the plane of the carboxyl­ate group and the norbornyl methano C-O bond is 4.5 (1)°, the methano C atom deviating by 0.141 (2) Å from this plane. In the crystal, mol­ecules pack as pairs of enanti­omers, with a distance of 3.747 (1) Å between the centroids of nearest parallel benzene rings.