Crystal structure and absolute configuration of dihydro-O-methyl-cancentrinemethine hydrobromide, a derivative of the alkaloid cancentrine

Abstract

The crystal and molecular structure and the absolute configuration of the title compound has been determined by X-ray diffraction methods. The crystals are orthorhombic with cell dimensions: a= 10·639 ± 0·002, b= 12·036 ± 0·004, and c= 26·979 ± 0·007 Å, space group P2₁2₁2₁, Z= 4. The structure was solved by the heavy-atom method. After refinement by least-squares methods using anisotropic thermal parameters, R was 0·072 for 2475 observed reflections. The molecule consists of two units derived from morphine and cularine, linked by a spiro-ring junction. The absolute configuration was determined and shows that the morphine-related fragment has the opposite configuration to that found in morphine.