Results 171 to 180 of about 2,321 (211)

Cleavage of depsides by tert-butyl alcohol

Phytochemistry, 1979
Abstract Depsides have been found to cleave readily on prolonged heating with t -butyl alcohol to give t -butyl esters and the free phenols.
Frank W. Bachelor, Ukken O. Cheriyan, Jerry D. Wong   +2 more
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Solid phase synthesis of depsides and depsipeptides

Tetrahedron Letters, 1999
Abstract A general solid phase methodology for the synthesis of depside and depsipeptide chains from optically active α-hydroxy acids and α-amino acids is reported. The automated preparation of depsides (97% yield per cycle) made up from the same enantiomer [i.e. H-[( S )-Man] 8 -OH, 1 ] † by both enantiomers [i.e. H-[( R )-Man-( S )-Man] 4 -OH,
Oliver Kuisle, Emilio Quiñoá, Ricardo Riguera   +2 more
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Synthesis of the Aliphatic Depside (+)-Bourgeanic Acid

The Journal of Organic Chemistry, 1994
The lichen metabolite (+)-bourgeanic acid (1) was synthesized in 12 steps and 3.4% overall yield from (R)-2-methyl-1-iodobutane (53) by a sequence which confirmed that this aliphatic depside is the self-este- rification product of (2R,3S,4R,6R)-2,4,6-trimethyl-3-hydroxyoctanoic acid.
James D. White, Alan T. Johnson
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Chlorogenic acids and related depsides

The Botanical Review, 1964
Isolation and Chemistry 668 General Isolation Procedures 668 The Chlorogenic Acids 671 Additional Quinic Acid Depsides 677 Other Phenylpropenoyl Depsides 680 Transesterification Reactions in Quinic Acid Depsides 681 The Chlorogenic Acid-Caffeine Complex ...
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Inhibition of Photosystem II of Spinach by Lichen-derived Depsides

Bioscience, Biotechnology, and Biochemistry, 1998
Barbatic acid, a lichen-derived depside, inhibited oxygen evolution in spinach thylakoid membranes. It also affected parameters of Chl fluorescence, (Fm'-F)/F and Fv/Fm. Using specific donors and acceptors of electrons, we found two sites of inhibition in the PS II complex.
T, Endo, T, Takahagi, Y, Kinoshita, Y, Yamamoto, F, Sato   +4 more
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Radiolysis of Quercetin in Methanol Solution:  Observation of Depside Formation

Journal of Agricultural and Food Chemistry, 2002
Radiolysis of the flavonol quercetin, a natural antioxidant, was performed in methanol. The degradation process was followed by HPLC analyses. The major product was identified as a depside (Q1) by NMR and LC-MS. The G(Q1) radiolytic factor was plotted versus the initial concentration of quercetin.
Abdelghafour, Marfak, Patrick, Trouillas, Daovy-Paulette, Allais, Yves, Champavier, Claude-Alain, Calliste, Jean-Luc, Duroux   +5 more
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A theory of biogenesis of lichen depsides and depsidones

Proceedings of the Indian Academy of Sciences - Section A, 1944
Lichen depsides and depsidones are considered to arise from a common source (XIV) which originates from aldol condensation between a hexose and a biose and elimination of water. Oxidation and reduction lead to various modifications of this C8 unit and increase in the length of the sidechain arises from condensation with simple sugars and reduction ...
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New Depsides in Stirtonia ramosa (Ascomycotina, Arthoniaceae)

The Bryologist, 1990
Stirtonia ramosa, a corticolous crustose lichen from the Andaman Islands, contains two new para-depsides, 4-O-demethylsuperconfluentic and 2'-O-methylnorsuperphyllinic acids. Chemical structures are proposed from microchemical identification of the hydrolysis products of the depsides and their methyl esters.
Chicita F. Culberson, Anita Johnson, P. G. Patwardhan, Urmila Makhija   +3 more
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Synthesis of Further b-Ketoalkyl Lichen Depsides

Australian Journal of Chemistry, 1997
The unambiguous total synthesis of the lichen depsides 2-O-methylglomelliferic acid (39), 4-O- methylhyperolivetoric acid (40), hyperconfluentic acid (41), microphyllinic acid (42), arthoniaic acid (43), 2′-O-methylmicrophyllinic acid (44), 2′-O-methylhyperphyllinic acid B (45), 4-O-methylsuperolivetoric acid (46), 2′-O-methylhyperphyllinic acid A (47)
John A. Elix, Judith H. Wardlaw
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Stenosporic acid, a new depside in Ramalina stenospora

Phytochemistry, 1970
Abstract Column chromatography of an extract of the lichen Ramalina stenospora Mull. Arg. yielded usnic acid (0·013%), a mixture of atranorin and chloroatranorin (0·007%), perlatolic acid (0·40%) and a new para-depside, stenosporic acid (0·37%). Stenosporic acid was proven to be 4-(2-hydroxy-6-propyl-p-anisate)-6-pentyl-β-resorcylic acid.
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