Results 121 to 130 of about 1,182 (166)

Tert-butanolysis of lichen depsides

Phytochemistry, 1984
Abstract The scope and limit of the tert-butanolysis of 12 lichen depsides is described. Neither 2-O-methylated nor 2-O-acetylated compounds are cleaved by heating with tert-butanol.
Siegfried Huneck
exaly   +2 more sources

Depsides in Sunflower Leaves

Nature, 1966
THIS communication reports our finding of neochlorogenic, isochlorogenic, and 3-O-feruloylquinic acids in the leaves of sunflowers, Helianthus annuus, Russian Mammoth variety. The well-known chlorogenic acid (3-O-caffeoylquinic acid) has been previously found in sunflowers by Urban1 and its presence there has been confirmed by Watanabe et al ...
A. ZANE, S. H. WENDER
openaire   +1 more source

Synthesis of Further Lichen Depsides

Australian Journal of Chemistry, 1993
The unambiguous total synthesis of 18 lichen depsides has been achieved by the condensation of an appropriately substituted orsellinic acid and protected phenol in the key step, followed by subsequent deprotection and/or secondary reduction. The natural occurrence of the first meta-depside involving substitution at the 5??-position of the B-ring has ...
JA Elix, CE Barclay, F David, FK Griffin, AM Hill, DB Mcconnell, JH Wardlaw   +6 more
openaire   +1 more source

Methyl β-Orcinolcarboxylate and Depsides from Parmelia furfuracea

Journal of Natural Products, 1985
Parmelia furfuracea, a common conifer lichen, produce antimicrobical constituents whose extracts have been utilized to give base materials for perfumes. Crude extracts of this lichen were tested against representative different class of microorganisms.
Caccamese, S., TOSCANO, Rosa Maria, Bellesia, F. b, Pinetti, A.   +3 more
openaire   +2 more sources

Depsides from the Petals ofPapaver rhoeas

Planta Medica, 2004
Two new depsides as well as the known p-hydroxybenzoic acid and its methyl ester, protocatechuic acid, 2-(4-hydroxyphenyl)-ethanol, 2-(3,4-dihydroxyphenyl)-ethanol and the flavonoids kaempferol, quercetin, luteolin and hypolaetin and the glycosides 3- O-beta- D-glucopyranosylquercetin (isoquercitrine), 3- O-beta- D-glucopyranosylkaempferol (astragaline)
Marita, Hillenbrand, Josef, Zapp, Hans, Becker   +2 more
openaire   +2 more sources

Synthesis of the lichen depsides pseudocyphellarin A and B

Australian Journal of Chemistry, 1984
The total synthesis of the fully substituted lichen depsides, pseudocyphellarin A (3-hydroxy-4-methoxycarbonyl-2,5,6-trimethylphenyl 3-formyl-2,4-dihydroxy-5,6-dimethylbenzoate) (1) and pseudocyphellarin B (3-hydroxy-4-methoxycarbonyl-2,5,6-trimethylphenyl 2,4-dihydroxy-3-hydroxymethyl-5,6-dimethylbenzoate) (2) is described.
JA Elix, L Lajide
openaire   +1 more source

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
openaire   +1 more source

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 ...
openaire   +1 more source

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
openaire   +1 more source

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
openaire   +1 more source