X-Ray crystallographic evidence for intermolecular hydrogen bonding, including a bifurcated hydrogen bond, between nitro and hydroxy groups in two 3-chloro-6-nitrobicyclo[2.2.1]heptan-2-ols

Abstract

The structures of 3-exo-chloro-6-exo-nitrobicyclo [2.2.1]heptan-2-exo-ol (7) and 3-exo-chloro-6-exo-nitrobicyclo[2.2.1]heptan-2-endo-ol (8), prepared in moderate yields by oxidation of 5-endo-nitrobicyclo[2.2.1]hept-2-ene (3) with chromyl chloride followed by reduction of the crude chloroketone mixture with sodium borohydride, were determined by X-ray crystallography. In compound (7), linear hydrogen bonds occur intermolecularly between the hydroxy and nitro groups, while in compound (8), the intermolecular hydrogen bonds between these groups are unsymmetrically bifurcated.