Orsellinic Acid Research Articles

A GENERAL SYNTHETIC METHOD FOR ORSELLINIC ACID MOIETY OF MACROLIDES BY THE PALLADIUM-CATALYZED CARBONYLATION OF ARYL IODIDE AND ITS APPLICATION TO ZEARALENONE SYNTHESIS

Abstract Palladium-catalyzed carbonylation of 1-iodo-2-phenylthiomethyl-4,6-dimethoxybenzene (9) with 10-iodo-6,2′-[1,3] dioxolane-2-decanol (10) afforded the corresponding ω-iodoalkyl ester of 2-phenylthiomethyl-4,6-dimethoxybenzoate (3) in 70% yield, which is the precursor of Zearalenone (1). 1-Iodo-2-phenylthiomethyl-4,6-dimethoxybenzene (9) was prepared from 3,5-dihydroxybenzoic acid (5a). This method of carbonylation offers a general and convenient synthetic method for an orsellinic acid moiety of orsellinic acid type macrolides.

A new route to 5-substituted resorcinols and related systems

Michael-type additions of phenylsulphinylacetate esters to αβ-unsaturated ketones produce cyclohexane-1,3-dione derivatives, which, after thermal elimination of benzenesulphenic acid, give the corresponding 5-substituted resorcinols, such as olivetol. The scope of this entry into other aromatic systems, such as 3,5-disubstituted and 2,3,5-trisubstituted phenols and orsellinic acid has been explored.

Ovosäure, ein neues tridepsid aus der flechte Parmelia substygia

The structure of ovoic acid, a new tridepside from the lichen Parmelia substygia Ras. has been elucidated as 2′- O-methylgyrophoric acid by 13C and 1H NMR, by UV spectroscopy and by hydrolysis to orsellinic and isoeverninic acids.

On the reaction of orsellinic acid carbanion with pyrylium salts

From the reaction of methyldimethyl orsellinate anion 1 with the pyrylium salt 2 the isocoumarin 5 was isolated in addition to the pyrones 3 and 4 . Reaction intermediates could be trapped as pyridines 6 and 7 .

Long-chain phenols. Part 16. A novel synthesis of homologous orsellinic acids and their methyl ethers

By the novel reaction of 3,5-dimethoxyfluorobenzene with n-alkyl-lithium compounds, followed by carbonation, homologous orsellinic acid dimethyl ethers (6-alkyl-2,4-dimethoxybenzoic acids) have been obtained. The reactions proceeded best with the homologues of methyl-lithium. These reactions are considered to occur by way of 3,5-dimethoxybenzyne. 2,4-Dimethoxyfluorobenzene did not form an aryne but gave 3-fluoro-2,6-dimethoxybenzoic acid instead. Decomposition with water of alkyl-lithium reaction mixtures from 3,5-dimethoxyfluorobenzene yielded 5-n-alkylresorcinol dimethyl ethers. Demethylation of 6-alkyl-2,4-dimethoxybenzoic acids with boron trichloride proceeded partially and selectively to give the 6-alkyl-2-hydroxy-4-methoxybenzoic acids, and completely with aluminium chloride to give the homologous orsellinic acids. Boron tribromide was less effective, but readily gave the 5-alkyl resorcinols from the corresponding dimethyl ethers.

ChemInform Abstract: TRIACETIC ACID LACTONE AS A POLYKETIDE SYNTHON: SYNTHESIS OF TORALACTONE AND POLYKETIDE‐TYPE ANTHRACENE DERIVATIVES

AbstractDas Carbanion (I) reagiert mit dem Triessigsäurelactonmethylether (II) zum Pyron (III), das basisch zum Derivat (IVa) des Polyketidmetaboliten Toralacton (IVb) cyclisiert wird.

ChemInform Abstract: TRIACETIC ACID LACTONE AND 2,6‐DIMETHYL‐Γ‐PYRONE AS POLYKETIDE SYNTHONS: SYNTHESES OF TORACHRYSONE AND ELEUTHERINOL DERIVATIVES

AbstractDas Carbanion (I) reagiert mit dem Pyron (II) zum ungesättigten Ketoester (III), der mit Lithiumdiisopropylamid zum Naphthalin (IVa) cyclisiert wird.

Triacetic acid lactone as a polyketide synthon: synthesis of toralactone and polyketide-type anthracene derivatives

Condensation of orsellinic and 6-methylsalicylic acid derivatives with triacetic acid lactone methyl ether gives naphthopyrones related to toralactone which can be converted in turn into polyketide-type anthracenes

Triacetic acid lactone and 2,6-dimethyl-γ-pyrone as polyketide synthons: syntheses of torachrysone and eleutherinol derivatives

Derivatives of torachrysone and eleutherinol have been made by reaction of a carbanion of an orsellinic acid derivative with γ-pyrones.

Condensation of diethyl acetonedicarboxylate. II.

Selfcondensation of diethyl acetonedicarboxylate (DADC) gave two types of products and the six kinds of the products were formed by using various catalysts. In order to elucidate the reaction mechanism of DADC for giving these products, the roles of catalysts were investigated. The formation mechanism of the orsellinic acid derivatives (1, 2, 3, and 4) was proposed, and the magnesium-DADC chelated complex (B) was recommended for the intermediate of these products. Furthermore, the mechanisms giving the coumarin derivatives (5 and 6) were discussed.

Tritium nuclear magnetic resonance spectroscopy. Part 7. New information from the tritium distribution in biosynthetically labelled penicillic acid

3 H N.m.r. spectroscopy is used to determine directly the regio- and stereo-specificity of the labelling in penicillic acid, biosynthesised by Penicillium cyclopium from [3H]acetate, from [2-3H]malonate, and from [3,5-3H]orsellinic acid. In particular, the method reveals the specific labelling of the 5-methylene group—largely trans to C-methyl—and the partial loss of label from the 5-positions relative to the 3-position and from the 3-position relative to the C-methyl group. It thus provides new information, which needs to be incorporated in any detailed proposals concerning the biosynthetic pathway and the enzyme stereochemistry. Such detail was not available from previous studies involving the use of 14C and 13C as tracers.

Synthesis of heterocycles, 186. The reaction of ethyl β‐aminocrotonate with orcinol and p‐orsellinic Acid

Synthesis of heterocycles, 186. The reaction of ethyl β‐aminocrotonate with orcinol and <i>p</i>‐orsellinic Acid

ChemInform Abstract: A NOVEL BIOGENETIC‐TYPE SYNTHESIS OF AN ORSELLINIC ACID DERIVATIVE

AbstractDas aus dem Lactonäther (I) mit Fluorsulfonsäuremethylester (II) hergestellte neue Pyryliumsalz (III) reagiert mit dem Wittig‐Reagens (IV) in Tetrahydrofuran über die nicht isolierbare′ Zwischenstufe (V) zu dem Orsellinsäurederivat (VI), ohne daß gleichzeitig Isomere als Nebenprodukte gebildet werden.

Lichen substances. V. Methylated derivatives of orsellinic acid, lecanoric acid, and gyrophoric acid from Pseudocyphellaria crocata

Two tridepsides (tenuiorin and methyl gyrophorate) have been identified as major constituents of Pseudocyphellaria crocata. Two similarly substituted didepsides (methyl evernate and methyl lecanorate) and the monomer methyl orsellinate have been isolated as new natural products. A number of additional orsellinic acid derivatives occur in the same lichen as identified by cochromatography with reference compounds, which reveals a biosynthetical fingerprint pattern based on methyl ester formation, 4-O-methylation, and condensation.

Lichen Substances VII. Identification of Orsellinate Derivatives from Lobaria linita

Lichen Substances VII. Identification of Orsellinate Derivatives from Lobaria linita

Intermediates in the penicillic acid biosynthesis in Penicillium cyclopium.

Feeding experiments using 14C-labelled precurosrs demonstrate the following sequence of the biological formation of penicillic acid in Penicillium cyclopium: orsellinic acid leads to 2-O-methylorsellinic acid leads to 1,4-dihydroxy-6-methoxy-2-methylbenzene leads 6-methoxy-2-methyl-benzoquinone(1,4)leads to penicillic acid.

A novel biogenetic-type synthesis of an orsellinic acid derivative

A synthesis of an orsellinic acid derivative (8) modelled on the polyketide mode of biosynthesis is described.

Relationship between fatty-acid and phenol synthesis in Aspergillus fumigatus.

Investigations have been conducted into the relationship between fatty acid and phenol synthesis in submerged cultures of Aspergillus fumigatus. Both groups of metabolites are derived from acetate but phenol synthesis only occurs at a late stage in the incubation period and is dependent on a change in the internal environment of the mycelium. Secretion of acetate‐derived phenols commenced many hours after exhaustion of ammonium ions from the culture medium, or transfer of mycelium to glucose solution. Lipid synthesis, however, was maintained at this stage and continued into the phenol‐secreting phase when sufficient glucose was present to provide the necessary substrates. The additional lipid formed was identified as triglyceride.The composition of fatty acids in the total lipids was very similar to that found in other Aspergillus sp. and related Ascomycetes and consisted principally of C18:2 with c16:0, c16:1, C18:0 and C18:1.Addition of 4‐fluorophenylalanine, but not cycloheximide, caused a rapid reduction in fatty acid synthetase activity and lipid synthesis, and abolished formation of orsellinic acid and trihydroxytoluene, the normal secreted products.Certain enzymes examined, including the dehydrogenases of the pentose phosphate pathway, maintained their specific activity during the “stationary” phase whereas fatty acid synthetase was present at greatly reduced activity. The activity of ATP citrate lyase was severely reduced to an undetectable level after approximately 40 h incubation; acetyl‐CoA would therefore not be made available for fatty acid, phenol or ergosterol synthesis after this time.Initiation of phenol synthesis cannot be ascribed simply to diversion of substrates from fatty acid synthesis or to reduction in fatty acid synthetase activity.

Biosynthesis of an antibiotic, siccanin

The biosynthetic pathway of the antibiotic siccanin ( 1) is based on the experiments using cell-free systems and intact cell systems of Helminthosporium siccans Drechsler. It involves (a) formation of trans-y-monocyclofarnesol ( 5) from mevalonic acid lactone or farnesyl pyrophosphate; (b) coupling reaction of the terpenic precursor with orsellinic acid; (c) oxidative conversion of presiccanochromenic acid ( 8), nto siccanochromenic acid ( 9), followed by decarboxylation to siccanochromen-A ( 10); and (d) epoxy-olefin type cyclization of siccanochromen-B ( 11) to siccanin ( 1).

Effect of inhibitors of protein synthesis on the formation of phenols derived from acetate and shikimic acid in Aspergillus fumigatus.

Trihydroxytoluene is the principal phenol secreted into the medium by submerged cultures of Aspergillus fumigatus (approximately 100 mg/l medium). Smaller amounts of tetrahydroxytoluene and its O-methyl derivative are also formed after longer periods of incubation. Supplementation of the medium with cycloheximide, 8-azaguanine or 5-methyltryptophan markedly reduced the secretion of these latter modified phenols but the production of orsellinic acid and trihydroxytoluene was not significantly affected. Addition of 4-fluorophenylalanine, however, strongly suppressed formation of the acetatederived phenols but various shikimic acid-derived phenols were secreted: 2,3-dihydroxybenzoic acid, 4-hydroxyphenylpyruvic acid and 4-hydroxybenzyl cyanide. In addition, 4-fluorophenylpyruvic acid was formed in good yield, presumably by transamination of the inhibitor. Degradation studies on 4-hydroxybenzyl cyanide indicated that the –CN group arose by retention of the α-carbon atom of tyrosine.