A Alectoronic acid

Fig. 37. A a-Alectoronic acid, GE. Bar 100 xm. B a-Alectoronic acid with a-coUatolic acid [from Cetrelia chicitae (W.Culb.) W. Culb. et C. Culb., GE. Bar 100 im. C Colensoic acid, GE. Bar 100 im. D a-CoUatolic acid, GE. Bar 100 Lim...

Hydroxybarbatic acid Nephroarctin a-Alectoronic acid Lutein... [Pg.117]

The best known depsidones are physodic acid, lobaric acid, norlobaridone, grayanic acid, alectoronic acid, diploicin, 4-0-methylphysodic acid, a-collatolic acid, lividic acid and variolaric acid. [Pg.10]

Elix, Ferguson, and Sargent (727) have studied the tautomerism of alectoronic acid (377), a-collatolic acid (382) and related depsides. The n.m.r. spectrum of alectoronic acid (Scheme 48) at ambient temperature exhibited a sharp two proton signal (8 4.06) due to the benzylic methylene protons of the A-ring side chain and a broad two proton signal (4.05 — 3.10) due to the protons H and Hg. At — 40 " C the signal for and Hg appeared... [Pg.183]

Many /5-orcinol depsidones discolor and decompose slowly without melting at temperatures above 240°-250° C, the decomposition being dependent upon the heating rate. For physodalic acid a decomposition range of 230°-260° C has been given, for salazinic acid 260°-280° C, and for fumarpro-tocetraric acid 245°-260°C. Presence of the solvent of crystallization may alter the mp drastically. Alectoronic acid (from benzene) melts at 193° C,... [Pg.648]

Methylphysodone (117) was isolated from Pseudevernia fur-furacea (339). 3-Alectoronic acid (118) and P-collatolic acid (119) are diphenyl ethers from Asahinea chrysantha (476) and A. scholanderi (476, 672) and exhibit an equilibrium between the keto-acid and lactol tautomers. 2" -0-Ethyl-P-alectoronic acid (120) from Alectoria sarmen-tosa (327) is probably an artefact formed during extraction by reaction of P-alectoronic acid with ethanol. [Pg.80]

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