Molecular and crystal structure of eupolauramine, a novel type of alkaloid from Eupomatia laurina

Abstract

Single-crystal X-ray structure analysis has shown the alkaloid eupolauramine, a constituent of the bark of Eupomatia laurina R. Br., is 6-methoxy-5-methyl-(4H)-1,5-diaza-acephenanthrylen-4-one. The ring system is novel. The previously reported spectroscopic and chemical properties of eupolauramine are satisfactorily explained in terms of the molecular structure.

Crystals are monoclinic, space group P2₁, a= 17.74(1), b= 9.22(1), c= 7.70(1)Å, β= 98.0(2)°, Z= 4. The structure was solved by direct (tangent refinement) procedures and refined by full-matrix least-squares methods to R 0.047 for 2 106 observed reflections. The two independent molecules in the asymmetric unit are enantiomorphic, but there are no significant differences between corresponding bond lengths and angles.