Structure of Chlorodesoxypatulinic Acid
BERGEL et al.1 found that the product of the action of ethanolic hydrogen chloride on patulin gave on hydrolysis a crystalline chloro-acid, C7H7O4Cl, now called Chlorodesoxypatulinic acid. Afterwards, Plattner et al.2 observed that the same acid was readily produced by the action of hydrogen chloride on patulin in moist ethereal solution. The expression (I) was originally deduced1 for Chlorodesoxypatulinic acid from its relationship to patulin, for which the structure (II) was assumed3. Recent developments in this Laboratory and in that of Plattner necessitated the abandonment of these views, and led the Swiss group2 to formulate Chlorodesoxypatulinic acid as (III), which was consonant with either of two new structures, (IV)4 and (V)2, put forward for patulin in Cambridge and in Zurich, respectively. We have now accumulated new evidence which requires that (III) in its turn be rejected, and which leads to a new view of the structure of chlorodesoxypatulinic acid which is consistent only with the structure (IV) for patulin.
Bioactivity studies of oxysporone and several derivatives
Recently oxysporone, a phytotoxic dihydrofuropyranone, was isolated along with two closely related compounds, afritoxinones A and B, from liquid cultures of Diplodia africana, an invasive fungal pathogen of Phoenicean juniper. In this study, eight derivatives were hemisynthesized and assayed for their phytotoxic and antifungal activities in comparison to the parent compound. Each compound was tested on non-host plants and on four destructive plant pathogens such as Athelia rolfsii, Diplodia corticola, Phytophthora cinnamomi and P. plurivora. The results on the phytotoxic activity showed that the dihydrofuropyranone carbon skeleton and both the double bond the hydroxy group of dihydropyran ring appeared to be structural features important in conferring activity. Although the data concerning the antifungal activity did not allow to extract any structure–activity relationships, it should be underlined that the conversion of oxysporone into the corresponding 4-O-benzoyl derivative led to a compound showing a good antifungal activity towards three out of the four organisms tested.
Liquid state 1H high field NMR in food analysis.
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