Methyl p-orsellinate

Hylands PJ, Ingolfsdottir K (1985) The isolation of methyl P-orsellinate from Stereocaulon alpinum and comments on the isolation of 4,6-dihydroxy-2-methoxy-3-methylacetophenone from Stereocaulon species. Phytochemistry 24 127-129... 

In both lichens the ketones co-occur with atranorin (110) and it has been pointed out by Culberson, Culberson and Johnson (78) that from the data available, (108) could not be distinguished from methyl P-orsellinate (111), a possible artefact of atranorin. 

Methyl 3-methoxysalicylate. Methyl 2-hydroxy-3-methoxybenzoate, 1545 Methyl mono-O-methyl-p-orsellinate. Methyl 2-hydroxy-6-methoxy-4-methylbenzoate, 1547... 

From 2,4-dihydroxy-3,6-dimethyl-5-chlorobenzoic acid and methyl P-orsellinate with TFAA From 2,4-dibenzyloxy-3,6-dimethyl-5-chlorobenzoic acid and methyl orsellinate with TFAA and subsequent debenzylation From 4-benzyloxy-2-methoxy-6-n-pentyl-benzoic acid and 2,3-dihydroxy-4-methoxy-6-n-pentylbenzoate with TFAA and subsequent debenzylation... 

Cladosporium sphaerospermum (Gomes et al. 2002). In addition, MIC values obtained from monoaromatic phenols (methyl beta-orsellinate and methyl and ethyl orsellinates) derived from various Icelandic lichen species were found equal or higher than usual preservatives (methyl- and propyl-p-hydroxybenzoates, o-... 

Also obtained by decarboxylation of 3-acetyl-p-orsellinic acid (3-acetyl-2,6-di-hydroxy-4-methyl-benzoic add) with copper in boiling quinoline [2691]. 

Penicillic acid (Figure 3.45), another micro-bially produced food contaminant with carcinogenic properties, is synthesized by cultures of Penicillium cyclopium and P. baarnense, and also features oxidative ring fission of an aromatic compound. This time orsellinic acid (Figure 3.25) is a precursor, and ring fission appears to proceed via a quinone, which is the result of decarboxylation, oxidation, and methylation reactions. Figure 3.45 also represents an over-simplistic rationalization of the ring fission process. 

Dibromo - 5 - methyl - 6 - carbethoxycyclohexa -1,3 - dione dissolved in coned. H2SO4, and allowed to stand 0.5 hr. at room temp. 2,4-dibromo-5-methyl-6-carboxycyclohexa-1,3-dione (Y 97%) mixed with 2-3 parts Pd-on-calcium carbonate and 2 N NaOH-soln., hydrogenated 6 hrs. at 40 p.s.i. orsellinic acid (Y 70%). — This sequence avoids sulfonation. R. A. Kloss and D. A. Clayton, J. Org. Chem. 30, 3566 (1965). 

Huneck S, Yoshimura I (1996) Identification of lichen substances. Springer, Berlin, p 493 Hussain MS, Fareed S, Ansari S et al (2012) Current approaches toward production of secondary plant metabolites. J Pharm Bioallied Sci 4 10-20 Ingolfsdottir K, Gudmundsdottir GF (2002) Effects of tenuiorin and methyl orsellinate from the lichen Peltigera leucophlebia on 5-/15-lipoxygenases and proliferation of malignant cell lines in-vitro. Phytomedicine 9 654-658... 

Preparation by hydrogenolysis of 2,2, 4 -tris-(benzyloxy)-3,5-dibromo-6-methoxy-4,6 -dimethyl-benzophenone (SM) in ethanol/trifluoroacetic acid mixture in the presence of 10% Pd/C at atmospheric pressure (quantitative yield). SM was obtained by condensation of 0-benzyl-0-methyl-3,5-dibromo-y-orsellinic acid— 2-(benzyloxy)-3,5-dibromo-6-methoxy-4-methylbenzoic acid—with orcinol dibenzyl ether in the presence of nifluoroacetic anhydride/trifluoroacetic acid mixture under nihogen in refluxing chloroform for 6.25 h [1376]. m.p. and Spectra (NA). 

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