Studies on fungal products. VII. The structures of meleagrin and 9-O-p-bromobenzoylmeleagrin.

The structure of meleagrin (1), isolated from Penicillium meleagrinum, was determined by X-ray crystallographic analysis of 9-O-p-bromobenzoylmeleagrin (7) monohydrate. The crystal structure of 7 monohydrate was determined by the heavy atom method : the final R value without hydrogen atoms was 0.094. The structure of meleagrin was established as the 9-O-demethyl compound of oxaline (4), isolated from Penicillium oxalicum. The absolute configurations at N1, C2, and C3 are S, S, and R, respectively.