trans-Reduction of 5-phenyl-1,2,3,4,5,6-hexahydroazepino[4,5-b]indole. X-Ray crystallographic study of the geometry of an intermolecular N–H ⋯ phenyl hydrogen bond

Abstract

The stereochemistries of the two isomeric products (5) and (6) obtained in equal amounts from trans-reduction of 3-benzyl-5-phenyl-1,2,3,4,5,6-hexahydroazepino[4,5-b]indole (3) have been determined by spectral and single-crystal X-ray analyses. Monoclinic crystals of (5) belong to space group P2₁/c, with a= 22.005(10), b= 10.270(5), c= 13.577(7)Å, β= 106.42(1)°, Z= 8. The crystal structure was solved by direct methods, and atomic positional and thermal parameters refined by least-squares calculations to R 0.051 over 3 293 reflections measured by diffractometer. The two molecules defining the asymmetric crystal unit have identical conformations and are associated in a like manner in the solid state by N–H ⋯ N (mean N ⋯ N 3.26 Å) and N–H ⋯ phenyl (mean calculated H ⋯ phenyl 2.32 Å) hydrogen bonds.