Ethyl orsellinate

Hydrogenolysis of 1-phenyltetrazolyl ether has been applied to deoxygenation of several heavily substituted phenols, for example, ethyl orsellinate (4a). 

The use of open-chain precursors for obtaining the benzenoid ring in anacardic and orsellinic acids has proved a fruitful approach. Ethyl 2-methoxy-6-methylbenzoate (synthesised through the Michael addition of ethyl acetoacetate virith but-2-en-al, followed by cyclisation and aromatisation), has been alkylated in an aprotic solvent after formation of the carbanion with lithium di-isopropylamide (refs. 113,114) to give the anacardic after hydrolysis and demethylation (a). In a similar way ethyl 2,4-dimethoxy-6-methylbenzoate (ethyl orsellinate), (formed from ethyl acetoacetate and ethyl crotonate followed by cyclisation aromatisation and methylation (ref. 115)), has been alkylated (ref. 116, 117). In this way the C.,5 orsellinic acid precursor [R = C14H29 in route (b)] of the component phenols in Anacardium occidentale has been synthesised (ref. 118) and the method indirectly affords another route to the cardol series. 

Bis - (2,4-dihydroxy-6-n-pr opyl) - Ethyl orsellinate Nordivaricatic acid... 

Ethyl orsellinate, Ethyl 2,4-dihydroxy-6-methylbenzoate (Orsellinsaureethylester, 2,4-Dihydroxy-6-methylbenzoesaureethylester)... 

Whalley WB (1949) The application of the modified Gattermann reaction to methyl and ethyl orsellinate. J Chem Soc 3278-3280... 

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-... 

PD-,K-,C+ red Anziaic acid, 4-(9-demethylbarbatic acid, erythrin, ethyl orsellinate, gyrophoric acid, lecanoric acid, methyl 3,5-dichlorolecanorate, methyl- -orsellinate, montagnetol, olivetoric acid, siphulin... 

Methyl and ethyl orsellinate Bacillus sublilis. Staphylococcus aureus. (436)... 

Kato T, Hozumi T (1972) Studies on Ketene and its Derivatives. XLIX. Reaction of Diketene with (i-Ketoesters to Give Ethyl Orsellinate, Divarate, Olivetol Carboxy-late and Sphaerophorol Carboxylate. Chem Pharm Bull 20 1574... 

Whalley WB (1949) The Application of the Modified Gattermann Reaction to Methyl and Ethyl Orsellinate. J Chem Soc 3278 72/. White FJ, James PW (1985) A New Guide to Microchemical Techniques for the Identification of Lichen Substances. British Lichen Soc Bull 57 1 722. White JD, Johnson AT (1990) Synthesis of the Lichen Metabolite (+)-Bourgeanic Acid and Conformational Analysis of its Dilactone. J Org Chem 55 5938 725. White JD, Johnson AT (1994) Synthesis of the Aliphatic Depside (+)-Bourgeanic acid. J Org Chem 59 3347... 

Homosckikaic acid (7) Gyrophoric acid (65) Orsellinic acid (79) Ethyl orsellinate (90) Lecanorin (91) Antigylcation Parmotrema cooperi (J. Steiner Zahibr.) Serus [108]... 

Fried s group at Syntex has described a similar synthesis of zearalenone employing a Wittig condensation and ring closure by intramolecular lactonization (Scheme 1.27). The aromatic residue 131 was constructed from the known ethyl o-orsellinate diacetate (130) by acid hydrolysis and methylation of the phenolic hydroxy groups. 

The first synthesis modelled on biomimetic lines was directed to obtaining anacardic acids by way of polyketides [237] and later to a (17 l)-orsellinic acid [43]. A less complicated approach based on the Michael addition of ethyl acetoacetate and ethyl octadec-2-enoate, has led to a C15 orsellinic acid, Fig (4)-56, 2,4-dihydroxy-6n-pentadecylbenzoic, considered to be the biogenetic precursor of the cashew phenols [238], notably cardol, by decarboxylation. The use of bromine at the aromatisation stage in this synthesis precluded the extension of the method to components with unsaturated side-chains, although bromination with copper(ii)bromide and thermal debromination offers an alternative procedure. In a more recent approach, by the use of an oxazole intermediate and its addition to ethyl acetoacetate, (15 0) and (15 1) anacardic acid have been obtained [239] as shown in Scheme 5a, b. The 8(Z),1 l(Z)-diene and 8(Z),1 l(Z),14-triene have also been synthesised [240] by way of ethyl 6-(7-formylheptyl)-2-methoxybenzoate (C), prepared from acyclic sources, rather than, as in previous work, by semisynthesis from the ozonisation of urushiol. 

Reaction with enol ethers of ethyl acetoacetate. Reaction of the ethyl enol ether of ethyl acetoacetate (1) with TiCla gives the derivative (2) of p-orsellinic acid the phenyl enol ether (3) under the same conditions is converted into the derivative (4) of o-orselUnic acid. ... 

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-... 

OH Preparation by hydrogenolysis of 2,2, 4,4 -tetrakis-(benzyloxy)-6,6 -dimethyl-benzophenone (SM) in the presence of 10% Pd/C in ethyl acetate (90%) [1376], SM was obtained by condensation of orcinol dibenzyl ether with orsellinic acid dibenzyl ether in methylene chloride in the presence of trifluoroacetic anhydride for 5 min (75%). 

Scott FE, Simpson TJ, Trimble LA, Vederas JC (1986) Biosynthesis of the Meroterpenoid Austin, by Aspergillus ustus Synthesis and Incorporation of C, 0-Labelled Ethyl 3,5-Dimethyl Orsellinate. J Chem Soc Chem Comm 214 Seifert P, Bertram C (1995) Usnic Acid Natural Preservation from Lichens. Seifen... 

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