Tridepsides

They are called didepsides, tridepsides, poly-depsides, etc., depending on the number of phenol residues they contain. Obtained from lichens, present in tea. 

JA Elix, VK Jayanthi, CC Leznoff. 2,4-Di-O-methylgyrophoric acid and 2,4,5-tri-O-methylhiascic acid. New tridepsides from Parmelia damaziana. Austral J Chem 34 1757-1761, 1981. 

The potential role of lichen metabolites in allelopathic interactions has recently been reviewed.9,27 The phytotoxic effect of certain lichen metabolites may play a role in the establishment of lichen populations. The depsides, barbatic acid and lecanorin, and the tridepside, gyrophoric acid, have been shown to inhibit... 

During the fractionation of the bioactive MEK extract of F. nisquallensis two inactive compounds, the sesquiterpene (-)-frullanolide (21) and the tridepside tenuiorin... 

Crustinic add. C24H20O11, Mr 484.42, needles, mp. 178-180 °C (decomp.). Tridepside from the lichen... 

C24H20O10, Mr 468.42, needles, mp. 220-225 °C (decomp.) soluble in acetone. A tridepside which, on hydrolysis with concentrated sulfuric acid, gives 3 molecules of orsellinic acid. It occurs in numerous lichens, especially species from the families Umbilicariaceae, Parmeliaceae, and Roccellaceae. iU/. Aust. J.Chem.48,1761 (1995)" Culberson, p. 119-120 Karrer, No. 1048 Phytochemistry 42, 839 (1996). -[CAS548-89-0]... 

Bryan AJ, Elix JA (1976) 2-0-Acetyltenuiorin, a new tridepside from the lichen Pseudo cyphellaria australiensis. Aust J Chem 29 1147-1151 Bryan AJ, Elix JA, Norfolk S (1976) Synthesis of orcinol tridepsides and aphthosin, an orcinol tetradepside. Aust J Chem 29 1079-1086... 

Elix JA, Engkanian U (1976a) 3-Hydroxyphysodic acid. Chemical corroboration of the structure of this lichen depsidone. Aust J Chem 29 2693-2699 Elix JA, Engkanian U (1976b) 4,5-Di-O-methylhiascic acid, a new tridepside from the lichens Parmelia pseudofatiscens and Parmelia horrescens. Aust J Chem 29 2701-2705... 

Elix JA, Ferguson BA (1978) Synthesis of the lichen depsides, olivetoric acid, confluentic acid and 4-0-methylolivetoric acid. Aust J Chem 31 1041-1045 Elix JA, Gaul KL (1986) The interconversion of the lichen depsides para- and metascrobiculin, and the biosynthetic implications. Aust J Chem 39 613-624 Elix JA, Jayanthi VK (1977) 5-0-Methylhiascic acid, a new tridepside from Australian lichens. Aust J Chem 30 2695-2704... 

Elix JA, Lajide L (1981b) 2 -0-Methyltenuioirin, 2"-0-methyltenuiorin and 2, 2"-di-0-methyltenuiorin. Three new tridepsides from the lichen Pseudocyphellaria faveolata. Aust J Chem 34 2005-2011 Elix JA, Lajide L (1984a) The identification of further new depsidones in the lichen Parmelia notata. Aust J Chem 37 857-866... 

Elix JA, Jayanthi VK, Wardlaw JH (1989b) 2-0-Methylhiascic acid, a new tridepside in the lichen Parmelinopsis neodamaziana. Aust J Chem 42 1423-1426... 

Elix JA, Jin Y, Adler MT (1989c) 3-Hydroxyumbilicaric acid and 3-methoxyumbilicaric acid, new tridepsides from the lichen Parmelinopsis bonariensis. Aust J Chem 42 765-770... 

Elix JA, Yu J, Tonsberg T (1991a) 4-0-Methylhiascic acid and 5-0-acetyl-4-0-methylhiascic acid, two new lichen tridepsides. Aust J Chem 44 157-163... 

Elix JA, Venables DA, Wedin M (1994f) Newdibenzofurans and depsides from the lichen Bunodophoron patagonicum, Aust J Chem 47 1335-1344 Elix JA, Barbero M, Giralt M, Lumbsch HT (1995a) 2"-0-Methylgyrophoric acid, a new lichen tridepside. Aust J Chem 48 1761-1765... 

Huneck S, Schreiber K, Sundholm G (1980b) Ovosaure, ein neues Tridepsid aus der Flechte Parmelia substygia. Phytochemistry 19 885-887... 

Huneck S, Porzel A, Schmidt J, Feige GB, Posner B (1993c) Crustinic acid, a tridepside from Umbilicaria crus-tulosa. Phytochemistry 32 475-477... 

Vinet C, Quilhot W, Garbarino JA (1990b) Studies on Chilean lichens, XIV. 2 -0-Methylhiascic acid, a new tridepside in Catillaria corymbosa. J Nat Prod 53 1025-1027... 

Secondary aliphatic acids, esters and related derivates Mononuclear phenolic compounds Depsides, tridepsides and benzyl esters Depsidones and diphenyl esters Depsones... 

The orcinol series The most conunon fate of acetate-polymalonate-derived phenolic acids in lichens is intermolecular esterification of two or three similar or identical units. For example, the carboxylic acid of one unit is joined to the hydroxyl para to the carboxylic acid of the second unit. Such esterifications lead to the para-depsides. A second esterification reaction leads to tridepsides. If an ester linkage joins the first unit to a position meta to the carboxylic acid of the second ring, a weta-depside results. 

Depsides, tridepsides, and tetradepsides consist of two, three, and four hydroxybenzoic acid residues linked by ester groups. These are the most numerous classes of secondary metabolites in lichens. More than one hundred Uchen compounds are depsidones, which have an additional ether bond between aromatic rings. Depsidones in Uchen are believed to arise by oxidative cycUzation of depsides. It has been found that depsidone and depside compounds such as atranorin, divaricatic acid, lecanoric acid, evemic acid, salazinic acid, physodic acid, and stictic acid possess important antimicrobial activity (Manojlovic et al. 2012 Kosanic et al. 2013, 2014a Rankovic et al. 2014). 

No clear mechanisms have been identified that specifically indicate how depsides, tridepsides, tetradepsides, depsidones, anthraquinones, and xanthones target microbial invasion. 

In all instances these mononuclear compounds were accompanied by the structurally related depsides and tridepsides. 

Well established techniques 170, 171) for the isolation and separation of depsides from mixtures of lichen acids include fractional crystallization, preparative layer chromatography and column chromatography. Vacuum liquid chromatography 124) provided a convenient and efficient modification of the latter technique and was used in separating a complex mixture of tridepsides from the crude extracts of Parmelia damaziana. 

Synthesis of -Orcinol para-Depsides, -Orcinol meta-Depsides, meta-Orcinol Depsides and Orcinol Tridepsides... 

As a typical example of tridepside synthesis, the preparation of 5-0-methylhiascic acid (227) is depicted in Scheme 35 122). Persulfate oxidation of ethyl 4-benzyloxy-2-hydroxy-6-methylbenzoate (273) in potassium hydroxide solution gave the corresponding 5-hydroxy derivative (274) from which 2,4-dibenzyloxy-5-methoxy-6-methylbenzoic acid (275) was prepared. Condensation of this acid with benzyl lecanorate (276) gave the... 

Di-O-methylhiascic Acid, a New Tridepside from the Lichens Parmelia pseudofatiscens and Parmelia horrescens. Austral. J. Chem. 29, 2701 (1976). 

Methoxy-2,4-di-0-methylgyrophoric Acid, a Novel Tridepside from the Lichen Parmelia subfatiscens. Austral. J. Chem. 34, 1153 (1981). 

Of the 43 structurally determined depsides, 37 are didepsides and five are tridepsides only one tetradepside has been discovered. Depsides have typical UV spectra with two bands, such as lecanoric acid with A ax O gio e) at 270 (4.3) and 307 nm (4.2). 

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