Structure and absolute configuration of viocidic acid: X-ray analysis of viocidic acid dihydrobromide

Abstract

The constitution and absolute stereochemistry of viocidic acid, a degradation product of viomycin, has been established by an X-ray crystal structure analysis of its dihydrobromide, C₈H₁₃N₅O₂,2HBr,3H₂O. Crystals are orthorhombic, space group P2₁2₁2₁, with Z= 4 in a unit cell of dimensions a= 8·17, b= 12·17, c= 15·22 Å. The atomic co-ordinates were determined by Fourier and least-squares calculations and the final R value was 7·6% for 1408 independent reflexions. The structure comprises dipositive C₈H₁₅N₅O₂ ions, bromide ions, and water molecules; hydrogen bonding is the dominant feature of the intermolecular packing.