Structure and chemistry of the perchlorate of anhydro-N-hydroxymethyldeoxyangustifoline

Abstract

The deoxy-analogue of N-hydroxymethylangustifoline was synthesised in order to establish whether it will undergo cyclisation or, as a result of an intramolecular nucleophilic attack by N(1), quaternisation. Analytical data, infrared spectra, and chemical properties of the new cation suggested that its structure could best be represeuted by a partial-bond formula. This was confirmed by an X-ray structure analysis of the perchlorate salt which crystallises in the monoclinic space group P2₁ in a unit cell with dimensions a= 7·27, b= 13·31, c= 8·74 Å, β= 103·0°. The first calculation of structure factors was based on the chlorine atom. The crystal structure was then solved by three-dimensional Fourier syntheses and least-squares calculations. The final value of R over 1353 independent reflexions was 10·5%. The molecular dimensions and the stereochemistry of the cation are discussed. The results confirm the structure and conformation of angustifoline.