Results 181 to 190 of about 1,764 (217)

Depsidone synthesis. XII. Some exploratory synthetic routes to highly functionalized depsidones

Australian Journal of Chemistry, 1978
Attempts to synthesize the depsidones virensic acid (1), physciosporin (2), and pannarin (3) by routes based on the Ullmann ether condensation and the Hems reaction are described. Selective functionalization of highly substituted p-xylenes by photobromination is reported.
T Sala, MV Sargent
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Depsidone synthesis. Part 19. Some β-orcinol depsidones

J. Chem. Soc., Perkin Trans. 1, 1981
The synthesis of the lichen depsidones 3,8-dihydroxy-1,4,6,9-tetramethyl-11-oxo-11H-dibenzo[b,e][1,4]-dioxepin-7-carboxylic acid (hypoprotocetraric acid)(4), 8-hydroxy-3-methoxy-1,4,6,9-tetramethyl-11-oxo-11H-dibenzo[b,e][1,4]dioxepin-7-carboxylic acid (O-methylhyprprotocetraric acid)(5), 4-formyl-3,8-dihydroxy-1,6,9-trimethyl-11-oxo-11H-dibenzo[b,e][1,
Tony Sala, Melvyn V. Sargent
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Depsidone synthesis. Part 11. Synthesis of some fungal depsidones related to nidulin

Journal of the Chemical Society, Perkin Transactions 1, 1978
The synthesis of 3-hydroxy-8-methoxy-1,9-dimethyl-6-(s-butyl)dibenzo[b,e][1,4]dioxepin-11-one (tridechlorodihydronidulin)(34), a derivative of the fungal depsidone nidulin (1), and of 3,8-dihydroxy-1,9-dimethyl-6-(s-butyl)dibenzo[b,e][1,4]dioxepin-11-one (tridechlorodihydro-O-nornidulin)(39), a derivative of the fungal depsidone tridechloro-O ...
Peter Djura, Melvyn V. Sargent
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Depsidone synthesis. IV. Caloploicin

Australian Journal of Chemistry, 1976
The synthesis of the lichen depsidone caloploicin (2,4,7-trichloro-3-hydroxy-8-methoxy-1,6,9- trimethyldibenzo[b,e][l,4]dioxepin-11-one) (1) by oxidative coupling of 5'-chloro-2,2',4-trihydroxy-4- methoxy-3',6,6'-trimethylbenzophenone (23), and subsequent steps, is described.
MV Sargent, P Vogel
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Depsidones from Anomalographis madeirensis

Biochemical Systematics and Ecology, 1999
0 ...
González, Antonio G., Hernández, Consuelo, Rodríguez, Elsa M., Del Carmen Alfayate, M., Bermejo, Jaime   +4 more
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Three New Lichen Depsidones

Australian Journal of Chemistry, 1987
The depsidones a- acetylconstictic acid (5-acetoxymethyl-1,4-dihydroxy-10-methoxy-8-methyl-3,7-dioxo-1,3-dihydro-7 H- isobenzofuro [4,5- b][l,4] benzodioxepin-ll-carbaldehyde ) (6), substictic acid (1,4-dihydroxy-10-methoxy-8-methy1-3,7-dioxo- 1,3-dihydro-7 H- isobenzofuro [4,5-b][1,4]benzodioxepin-11-carbaldehyde) (7) and conphysodalic acid (9 ...
JA Elix, KL Gaul, PW James, OW Purvis
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ChemInform Abstract: DEPSIDONE SYNTHESIS. PART 16. BENZOPHENONE‐GRISA‐3′,5′‐DIENE‐2′,3‐DIONE‐DEPSIDONE INTERCONVERSION: A NEW THEORY OF DEPSIDONE BIOSYNTHESIS

Chemischer Informationsdienst, 1981
AbstractOxidative Kupplung der substituierten 2,2′‐Dihydroxy‐4‐methoxy‐benzophenone (I), (IV) bzw. (VII) mit K3 [Fe(CN)6] unter optimalen Bedingungen liefert die Grisadiendione (II), (V) bzw. (VIII), die sich bei Thermolyse in fester Form oder in Lösungsmitteln wie TFA/ CHz C12, Diphenylether oder Phenetol in die Depsidone (III), (VI) bzw.
T. SALA, M. V. SARGENT
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Depsidone synthesis. III. Grayanic acid

Australian Journal of Chemistry, 1976
The structure of the lichen depsidone grayanic acid (1) (6-heptyl-8-hydroxy-3-methoxy-1-methyl-11- oxo-11 H -dibenzo[b,e][1,4]dioxepin-7-carboxylic acid) proposed by Shibata and Chiang was confirmed by the synthesis firstly of methyl O -methylgrayanate (19), and then of grayanic acid itself. The key step in both syntheses was an Ullmann reaction.
P Djura, MV Sargent
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Antioxidant activity of depsides and depsidones

Phytochemistry, 1994
The antioxidant activity of lichenic metabolites, depsides and depsidones, was assessed by their effects as inhibitors of rat brain homogenate auto-oxidation and beta-carotene oxidation. The results obtained in both systems indicate that lichenic metabolites afford a moderate protection in the microM concentration range. The largest effect was measured
M E, Hidalgo, E, Fernández, W, Quilhot, E, Lissi   +3 more
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Two New Depsidones from Parmelia saxatilis

Chemistry of Natural Compounds, 2021
Two new depsidones, diffractione B (1) and salazinin A (2), and two known compounds, the dibenzofuran derivative usnic acid (3) and depsidone salazinic acid (4), were isolated from Parmelia saxatilis. The structures of the isolated compounds were identified by spectral analysis and comparison with literature data.
null Xigurigan, null Tunuomula, null Haliga, Shu Zhen Bai, null Ganchimeg, null Qirigeer, Li Guo Yang, Laxinamujila Bai   +7 more
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