Structure of daphmacrine, an alkaloid from Daphniphyllum macropodum: X-ray analysis of daphmacrine methiodide

Abstract

Crystals of daphmacrine methiodide (acetone solvate) are orthorhombic, a= 14·23, b= 24·85, c= 10·02 Å, Z= 4, space group P2₁2₁2₁. The structure was determined with Mo-K_α scintillation counter data from Patterson and Fourier syntheses, and refined by least-squares methods, the final R being 0·089 for 1834 observed reflexions. The absolute configuration was determined by the anomalous dispersion method. The molecule consists of two cage-structures which are linked by a flexible chain of two carbon atoms. The larger nitrogen-containing portion has the same structure as that in related daphniphylline compounds; the smaller oxygen-containing portion consists of a six-membered carbocyclic ring in the chair form, bridged by carbon and oxygen atoms to form a five-membered lactone, with methyl groups substituted at each bridged by carbon and oxygen atoms to form a five-membered lactone, with methyl groups substituted at each bridgehead. The bond lengths and valency angles do not differ from normal values.