4-(2-Hydroxyphenyl)-2-phenyl-2,3-dihydro-1H-1,5-benzodiazepine and the 2-(2,3-dimethoxyphenyl)-, 2-(3,4-dimethoxyphenyl)- and 2-(2,5-dimethoxyphenyl)-substituted derivatives

Abstract

The 1,5-benzodiazepine ring system exhibits a puckered boatlike conformation for all four title compounds [4-(2-hydroxyphenyl)2- phenyl-2,3-dihydro-1H-1,5-benzodiazepine, C21H18N2O, (I), 2-(2,3-dimethoxyphenyl)-4-(2-hydroxyphenyl)-2,3-dihydro- 1H-1,5-benzodiazepine, C23H22N2O3, (II), 2-(3,4-dimethoxyphenyl)- 4-(2-hydroxyphenyl)-2,3-dihydro-1H-1,5-benzodiazepine, C23H22N2O3, (III), and 2-(2,5-dimethoxyphenyl)4-( 2-hydroxyphenyl)-2,3-dihydro-1H-1,5-benzodiazepine, C23H22N2O3, (IV)]. The stereochemical correlation of the two C-6 aromatic groups with respect to the benzodiazepine ring system is pseudo-equatorial-equatorial for compounds (I) (the phenyl group), (II) (the 2,3-dimethoxyphenyl group) and (III) (the 3,4-dimethoxyphenyl group), while for (IV) (the 2,5-dimethoxyphenyl group) the system is pseudo-axial- equatorial. An intramolecular hydrogen bond between the hydroxyl OH group and a benzodiazepine N atom is present for all four compounds and defines a six-membered ring, whose geometry is constant across the series. Although the molecular structures are similar, the supramolecular packing is different; compounds (I) and (IV) form chains, while (II) forms dimeric units and (III) displays a layered structure. The packing seems to depend on at least two factors: (i) the nature of the atoms defining the hydrogen bond and (ii) the number of intermolecular interactions of the types O-H center dot center dot center dot O, N-H center dot center dot center dot O, N-H center dot center dot center dot pi(arene) or C-H center dot center dot center dot pi(arene).