Lecanoric acid

Leit-vermfigen, n. conducting power, (Elec.) conductance conductivity, -wert, m. (E/ c.) conductance, admittance, or susceptance. -zahl, /. (coefficient of) conductivity. Lekanorsaure, /. lecanoric acid. 

Analytical Litmus oligomer of lecanoric acid, orceins and processing of lidi s... 

These lichens contain a number of peculiar acids (lecanoric acid erythric acid, roccellic acid, c.), which are split up by alkalies, the final products being orcin, CeH3CH3(OH)2, and erythrite, C4H10O,. 

Cudbear. Crottle. Common names for the lichen Ochrolechia tartarea L., Lecanoraceae and for the coloring matter from this and other lichens, especially Lecanoraceae and Roccellaceae. A source of litmus, q.v. Acids in lichens (e.g. lecanoric acid) hydrolyze to orcinol, q. v., which, in the presence of ammonia can be oxidized to the dye orcein, q.v. The dyes French Purple, Persio, Orchil, and Orseitles derive from the salts of orcein Colour Index Vol. 3 (3rd ed-, 1971) p 3241. 

CH2OH R = H, CHj. Most D. are didepsides, such as, e.g., atranorin, chloroatranorin, gyrophoric acid, and lecanoric acid. In some D. (e. g., alectorialic acid and barbatolic acid) the acid part (S) is linked with a benzylic hydroxy group of the A part. The structures of about 100 D. isolated from lichens have been elucidated by hydrolysis and alcoholysis to the corresponding carboxylic acids or esters (S part) and to the phenols (A part), respectively. 

C20H22O10, Mr422.39, needles, mp. 156-157 °C, [aJo +8°. Ester of lecanoric acid with erythritol. E. occurs, e. g., in the lichen family Roccellaceae and furnishes the bitter-tasting montagnetol (C12H1JO7, Mr 272.25,... 

Depsides, in which esterification to links two polyketide-derived units [such as lecanoric acid (50)] (Fig. 5.24), are quite common among lichens (Weiss and Edwards, 1980). Many of these compounds are strongly allelopathic and are responsible for the death of trees inhabited by the dense growth of lichens (Cutler, 1992). 

Fischer followed Schiff and supposed that tannins are condensation products of substituted hydroxybenzoic acids. He found that these, which he called depsides SeifieiVy to tan), have some resemblance to tannins. Tannin is a condensation product of gallic acid but always contains glucose. A synthetic pentadigalloylglucose had some resemblance to tannin. A compound of this kind with a mol. wt. 4021 was prepared. From experiments of Kostanecki and V. Lampe, Freudenberg assumed that catechin is related to the flavones and anthocyanidins (see p. 863). Orsellinic acid (see p. 400) was shown to be closely related to gallic acid, and lecanoric acid from lichens to be a didepside (/)-diorsellinic acid). ... 

This view was confirmed more directly when 5-methylorcylaldehyde (XXIV) but not orcylaldehyde was converted to substituted toluquinols and gliorosein (XXV) by Gliocladium roseum, implying that the C-methyltrans-ferase concerned could not accept the aromatic orcylaldehyde (Steward and Packter, 1968). In addition, whereas acetate (Yamazaki et al., 1%5) and or-sellinic acid (Yamazaki and Shibata, 1966) were both incorporated into the depside lecanoric acid (XXVI) (derived by esterification of two molecules of orsellinic acid) in the lichen Parmelia tinctorum, orsellinic acid was not converted to the related atranorin (XXVIl) (Yamazaki and Shibata, 1966) this... 

Acetyl CoA 6-Methyl-salicylic acid, acetophenones, lecanoric acid, patulin, coniine, gallic acid (D 3.3.1) Eugenone, citrinin, sepedonin, coumarin derivatives (D 3.3.2) Plumbagin (D 3.3.3) Griseo-fulvin (D 3.3.4) Anthra-quinones, ergochromes (D 3.3.5) Afla-toxins (D 3.3.6)... 

Polyketides of this group are either carbocyclic compounds (like 6-methyl-salicylic acid) hydroxylated acetophenones, or possess an 6-membered (asperlin, coniine) or 7-membered (stipitatonic acid) N- or 0-heterocyclic ring. Often dimeric compounds occur, e.g., lecanoric acid. 

Congeneric chemotypes show simple replacement of one compound. Pseudevernia furfuracea (L.) Zopf occurs in Europe in two races containing olivetoric or physodic acids, while the race from North America synthesizes lecanoric acid. 

Stereocaulon curtatum Atranorin Lecanoric acid Miriquidic acid Lecanoric acid Hamada and Ueno (1990)... 

Hypothamnolic acid small rhombic crystals Imbricaric acid large needles Lecanoric acid thin curved needles Lecanoric acid prisms... 

Atranorin, chloroatranorin, pannarin Erythrin, gyrophoric acid, lecanoric acid Dibenzofuranes Quinones... 

Fig. 29. A Imbricaric acid [from Cetrelia cetrarioides (Del. ex Duby) W. Culb. et C. Culb.)] GE. Bar lOOjLim. B Lecanoric acid, GE. Bar 100 im. C Lecanoric acid (from Parmelia tinctorum NyL), GE. Bar 100 im. D Lecanoric acid, GE. Bar 10 jim.

T etrahydroxy-3-ethyl-naphtho-2,6-quinone a-Amyrin Lecanoric acid P-Ordnolcarboxylic acid Glomelliferonic acid 2,4-Dichlorolichexanthone Picrolichenic acid Taraxanthin Haemoventosin Orsellinic acid Lepranthin Siphulin Thiomelin 5-Chloro-4-0-... 

Diploschistesic acid has an infrared spectrum and an Rp value very similar to that of lecanoric acid, from which it can easily be differentiated by its yellow colour reaction with bis-diazotized benzidine on the TLC plate. Lecanoric acid gives a deep red colour with bis-diazotized benzidine... 

Deriv Triacetyllecanoric acid, prisms, MeOH, mp 190-191 °C, from lecanoric acid with Kcfi-... 

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