Bildung,Kristallstruktur und absolute Konfiguration von (−)-N-(Chloromethyl)galanthaminium-chlorid

Formation, X-Ray Crystal Structure, and Absolute Configuration of (?)-N-(Chloromethyl)galanthaminium Chloride The acetylcholinesterase inhibitor galanthamine ( 1 ), main alkaloid of several Narcissus species, readily forms a quaternary ammonium salt by reaction with the solvent CH₂Cl₂. The structure and absolute configuration of (?)-N-(chloromethyl)galanthaminium chloride ( 2 ) were determined by X-ray diffraction (R = 0.075 for 2775 observed independent reflexions) and NMR spectroscopy. The tetragonal crystals (space group P4₃) contain two crystallographically independent cations which do not differ significantly from one another. The CH₂Cl group is attached to the quaternary N-atom in stereospecific (R)-configuration. In the crystal, the configurational position of the Me group at the N-atom of 2 differs from that of the crystalline free base 1 . Hydrogen bonding is observed from the OH group at C(3) of 2 to the Cl^? anion or to the Cl-atom of an adjacent cation.