West African timbers. Part XVIII. Some reactions of Cedrela odorata substance “B” and khayasin

Abstract

Two closely related compounds, the diketone Cedrela odorata B (Ia) and khayasin (Ib), the isobutyrate of the corresponding hydroxyketone, have been obtained from the heartwood of trees belonging to the family Meliaceae. Some derivatives in which the lactone has been opened are described; one (IVa) is shown to arise by an interesting rearrangement, in which a cyclopropane ring is formed. The preparation of deoxyandirobin (X) from methyl angolensate (IV) is also described, and the n.m.r. spectra of all new compounds are recorded.