Haemoventosin.

Revised Structure of Haemoventosin

“…Reaction of haem oven tosin with acetic anhydride/sulphuric acid gave a product whose physical properties corresponded to those reported for the monoacetate prepared using acetic anhydride/pyridine [1]. Monoacetylhaemoventosin reveals in the carbonyl region of the IR spectrum bands at 1716 (quinone CO) and 1750 cm -1.…”

“…The finding of Bruun and Lamvik [1] that haemoventosin can be hydrolyzed with 10% N aOH to a compound, m.p. ca.…”

“…Haemoventosin has a centre of chirality at C-3 and should be optically active. Bruun and Lamvik [1] did not report the optical rotation of haemo ventosin or its acetate. We found that monoacetyl haemoventosin indeed is optically active; it has the large specific rotation of [a]57824 + 354.5 and the CD spectrum is shown in Fig.…”

“…It is noteworthy that Bruun and Lamvik [1] gave few details of the 'H NMR spectrum of monoacetylhaemoventosin; similarly Zeeck et al [10] did not report any 'H NM R data for 10-0-acetyl-sw?/-xanthomegnin 11, which might be expected to dis play similar conform ational behaviour to 4, and similar complications in the NMR spectra.…”

“…(Lecanoraceae)] is characterized by blood red apothecia, the colour of which turns to blue on treatm ent with potassium hydroxide. Bruun and Lamvik [1] isolated the pigment (haem oventosin) of the apothecia and proposed structure 1 for this lichen metabolite. Twenty years later Maksimov et al [2] put forward the alternative o-quinonoid structure 2 for haemoventosin which they isolated from O phioparm a lapponica (Rasänen) Hafellner & R. W. Rogers (syn.…”