- Zearalenone mimics: Synthesis of (E)-6-(1-Alkenyl)-substituted β-resorcylic acid esters
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Two versatile strategies for the synthesis of mimics of the Fusarium mycotoxin zearalenone (1) have been developed. Optimized preparation of (E)-6-(1-alkenyl) substituted β-resorcylic acid esters was realized via ortho-directed lithiation of variable substrates combined with allylation/isomerization or via formylation/Schlosser-Wittig olefination using different protective group patterns. Spontaneous decarboxylation of (E)-6-(1-alkenyl) substituted β-resorcylic acids indicated the influence of this substituent on the chemical behavior of these compounds. These mimics were already used for the development of optimized standard protocols for the synthesis of phase II metabolites of ZEN (glucosides, glucuronides), and further applications (i.e., sulfate conjugates) are still under investigation. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Mikula, Hannes,Hametner, Christian,Froehlich, Johannes
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p. 1939 - 1946
(2013/05/22)
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- Radical-scavenging activity of orsellinates
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Lichens are an important source of phenolic compounds and have been intensively investigated for their biological and pharmacological activities. Lecanoric acid (1), a lichen depside, was isolated from a Parmotrema tinctorum specimen and treated with alcohols to produce orsellinic acid (2) and orsellinates (3) to (9) (2,4-dihydroxy-6-n-methyl benzoates). Free radical scavenging activity of methyl (3), ethyl (4), n-propyl (5), n-butyl (6), iso-propyl (7), sec-butyl (8), tert-butyl (9) orsellinates was evaluated using 2,2′-diphenyl-1-picrylhydrazyl (DPPH) method. Results showed that chain elongation of methyl (3) to n-butyl (6) causes a rise in the antioxidant activity. However, iso-propyl (7) and tert-butyl (9) were more active than the correspondent linear compounds, although sec-butyl (8) was less active among the chain ramified compounds. All the orsellinates were less active than lecanoric acid (1) and orsellinic acid (2). Orcinol (10) and resorcinol (11) were also determined for comparison with activities of orsellinates. Gallic acid (12) was used as control.
- Lopes, Thiago Inacio Barros,Coelho, Roberta Gomes,Yoshida, Nidia Cristiane,Honda, Neli Kika
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experimental part
p. 1551 - 1554
(2009/09/06)
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- Improved Synthesis of Dichloroisoeverninic Acid
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The Dichlorination of methyl isoeverninate 7a gave the geminal dichloroketone 12 as the major product.The title compound 1 was therefore synthesized via dichlorination of 4-protected methyl orsellinate 5a using the pivaloyloxy-function as a new protecting group in resorcyclic acids chemistry. - Keywords: 3,5-Dichloro-4-hydroxy-2-methoxy-6-methylbenzoic Acid, Dichloroisoeverninic Acid
- Dornhagen, Juergen,Scharf, Hans-Dieter
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p. 1541 - 1549
(2007/10/02)
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