Structural elucidation and solution conformation of the novel herbicide hydantocidin

Abstract

The structure of a novel herbicide, hydantocidin isolated from the fermentation broth of Streptomyces hygroscopics SANK 63584, was determined by the combined analysis of MS and ¹H NMR spectra. Hydantocidin is a novel spiro compound containing a subofuranoid ring, at the anomeric position of which a hydantoin ring is used such that the C(1)–N(1) linkage is β. The relative configuration and the conformation in solution was determined by quantitative analysis of the NOE spectra and T₁ values. In CD₃OD and [²H₆]DMSO (dimethyl sulphoxide) solutions, the ribofuranose moiety of hydantocidin was found to be fixed in a C₂-endo conformation, probably due to the rigidity of the spiro structure and hydrogen bonding between 3-OH and the carbonyl group at C-4′.