Structure of α-hydroxysantonin and some aspects of the stereochemistry of related eudesmanolides and guaianolides

Abstract

Chemical and spectroscopic evidence shows that the principal metabolite of a-santonin isolated from the urine of dog, α-hydroxysantonin, has structure (Ic; R = H, R' = OH). P.m.r. evidence shows that artemisin has the same configuration at C6, C7, and C11 as α-santonin and that 6-epiartemisin has the same configuration at C6, C7, and C11 as 6-epi-α-santonin. β-Santonin is the C11 epimer of a-santonin and the configuration at C6 and C7 in 1-desmotroposantonin is analogous to that in 6-epi-a-santonin. The p.m.r. spectra of ψ-santonin, lumisantonin, isophoto-α-santonic lactone, and 6-epi-isophoto-α-santonic lactone are discussed.