Oxidation of alkoxyphenols. XX. Ring cleavage and lactone formation in the oxidation of a Biphenyl-2,2'-diol by lead tetraacetate

1977 ◽  
Vol 30 (9) ◽  
pp. 1971 ◽  
Author(s):  
FR Hewgill ◽  
DG Hewitt ◽  
GB Howie ◽  
WL Spencer
Keyword(s):  
Carboxylic Acid ◽  
Lead Tetraacetate ◽  
Ring Cleavage

Two products in the lead tetraacetate oxidation of 3,3?-di-t-butyl- 5,5?-dimethoxybiphenyl-2,2?-diol have been shown to be (E)-7-t-butyl-5- methoxy-3-[(E)-2?-methoxy-5?,5?-dimethyl-4?-oxohex-2?- enylidenelbenzofuran-2(3H)-one (1) and its (Z,Z) isomer (3). Treatment of these with base causes rearrangement to (E)-8-t-butyl-2-(3?,3?- dimethyl-2?-oxobutylidene)-6-methoxy-2H-1-benzopyran-4-carboxylic acid (13). Further treatment with base produces pinacolone and 8-t-butyl-6- methoxy-2-oxo-2H-1-benzopyran-4-carboxylic acid (14). The latter has been synthesized from 2-t-butyl-4-methoxyphenol via 7-t-butyl-5- methoxy-2,3-dihydrobenzofuran-2,3-dione (15).

Oxidations with lead tetraacetate. IV. Oxidations of 1,3-benzodithioles

1983 ◽  
Vol 36 (12) ◽  
pp. 2499 ◽  
Author(s):  
C Aromdee ◽  
ER Cole ◽  
G Crank
Keyword(s):  
Carboxylic Acid ◽  
Lead Tetraacetate ◽  
Oxidation Products ◽  
Ring Cleavage ◽  
Methyl Group

Oxidations of 2,2-dialkyl and spiro[1,3-benzodithiole-2,1'-cycloalkanes] with lead tetraacetate gave mainly sulfoxides and disulfoxides. The stereochemistry of these products was elucidated by n.m.r. spectroscopy. Oxidation of 2-methyl-2-aryl derivatives gave sulfoxides as minor products; here the main products were derived from attack on the methyl group forming acetoxy, diacetoxy, formyl and carboxylic acid derivatives and ring cleavage products. 2,2-Diaryl derivatives also formed small amounts of sulfoxides but ring cleavage products were predominant. Monosubstituted benzodithioles were very reactive and produced a variety of oxidation products, mostly unidentified.

Improved synthesis of anti-sesquinorbornene

1984 ◽  
Vol 62 (9) ◽  
pp. 1840-1844 ◽  
Author(s):  
Karl R. Kopecky ◽  
Alan J. Miller
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Lead Tetraacetate ◽  
Carboxyl Group ◽  
Silver Acetate ◽  
Benzenesulfonyl Chloride ◽  
Methoxide Ion ◽  
Hydrolysis Of ◽  
Monomethyl Ester

Treatment of methyl hydrogen decahydro-1,4:5,8-exo,endo-dimethanonaphthalene-4a,8a-dicarboxylate with lead tetraacetate in benzene – acetic acid replaces the carboxyl group by an acetoxy group. Hydrolysis of this product with 25% sulfuric acid at 130 °C forms 8a-hydroxydecahydro-1,4:5,8-exo,endo-dimethanonaphthalene-4a-carboxylic acid 10. The reaction between 10 and benzenesulfonyl chloride in pyridine containing triethylamine at 95 °C produces anti-sesquinorbornene 1 in 34% yield. In the absence of triethylamine 1 is converted to the hydrochloride. The iodohydroperoxide of 1 is converted by silver acetate at 0 °C to the diketone in a luminescent reaction. The 1,2-dioxetane could not be isolated. Decahydro-1,4:5,8-exo,exo-dimethanonaphthalene-4a,8a-dicarboxylic anhydride is converted slowly by methoxide ion in methanol at 150 °C to the monomethyl ester which then undergoes demethylation. The isomeric exo,endo anhydride undergoes reaction readily with methoxide ion at 80 °C.

scholarly journals Alkoxide-induced ring opening of bicyclic 2-vinylcyclobutanones: A convenient synthesis of 2-vinyl-substituted 3-cycloalkene-1-carboxylic acid esters

2012 ◽  
Vol 8 ◽  
pp. 650-657 ◽  
Author(s):  
Xiufang Ji ◽  
Zhiming Li ◽  
Quanrui Wang ◽  
Andreas Goeke
Keyword(s):  
Carboxylic Acid ◽  
Ring Opening ◽  
Claisen Rearrangement ◽  
Ring Cleavage ◽  
Unsaturated Ester ◽  
Supplementary Method ◽  
Convenient Synthesis ◽  
High Yields ◽  
Acid Esters

The fused 2-vinyl or 2-phenyl substituted cyclobutanones 4 undergo stereoselective ring openings by the action of alkoxide ions (t-BuO− or MeO−) to produce novel vicinally disubstituted cycloalkene derivatives 5 and 6 in moderate to high yields. The ring cleavage usually occurs with complete regioselectivity. The accessibility of γ,δ-unsaturated ester or acid derivatives makes this transformation a good supplementary method for the well-established Johnson–Claisen rearrangement.

The camphenehydro (methylcamphenilyl) and isobornyl (bornyl) cations. III. Oxidative decarboxylation of carboxylic acids with lead tetraacetate

1974 ◽  
Vol 27 (3) ◽  
pp. 603 ◽  
Author(s):  
GE Gream ◽  
CF Pincombe ◽  
D Wege
Keyword(s):  
Carboxylic Acid ◽  
Marked Change ◽  
Lead Tetraacetate ◽  
Dimethyl Sulphoxide ◽  
Oxidative Decarboxylation ◽  
Propanoic Acid ◽  
Acid Yield ◽  
Cupric Acetate ◽  
Initial Generation ◽  
Almost All

The oxidative decarboxylation of exo- and endo-bornane-2-carboxylic acid, exo- and endo-2,3,3- trimethylnorbornane-2-carboxylic acid and a-campholenylcarboxylic acid [3-(2',2',3'-trimethyl- cyclopent-3'-eny1)propanoic acid] with lead tetraacetate in benzene and dimethyl sulphoxide (each containing pyridine) in the presence, and absence, of cupric acetate has been investigated. The mode of formation of almost all the products can be satisfactorily rationalized in terms of the initial generation of radicals. In the case of exo- and endo-bornane-2-carboxylic acid, the derived bornyl radical forms organolead and organocopper derivatives that decompose in three ways: (1) by heterolysis by the direct route to give the equilibrating isobornyl and camphenehydro cations, (2) by a cyclic cis-elimination to give bornylene and (3) by an SNi process to give isobornyl and bornyl acetates. exo- and endo-2,3,3-Trimethylnorbornane-2-carboxylic acid yield the 2,3,3-trimethyl- norborn-2-yl radical which is converted into the equilibrating camphenehydro and isobornyl cations either by one-electron oxidation by lead species or via organolead or organocopper derivatives which undergo heterolysis. Processes involving cyclic cis-elimination and SNi substitution may also operate in the organometallic derivatives derived from the tertiary radical. a-Campholenylcarboxylic acid yields the a-campholenyl radical which, in the absence of cupric acetate, undergoes in the main cyclization to give the 2,3,3-trimethylnorbornyl radical. The resulting mixture of products is similar to that obtained from exo- and endo-2,3,3-trimethylnorbornane-2- carboxylic acid. In the presence of cupric acetate, the a-campholenyl radical is trapped at least to the extent of 50% in benzene and 80% in dimethyl sulphoxide to give the corresponding organo- copper derivative which undergoes a cyclic elimination to give 2,3,3-trimethyl-4-vinylcyclopentene and may undergo heterolysis by the x-route to give the camphenehydro and isobornyl cations. A marked change in the composition of the products on changing the solvent from benzene to dimethyl sulphoxide is observed only in the case of a-campholenylcarboxylic acid in the presence of cupric acetate.

scholarly journals Biotransformation of Biphenyl by Paecilomyces lilacinus and Characterization of Ring Cleavage Products

2001 ◽  
Vol 67 (4) ◽  
pp. 1551-1557 ◽  
Author(s):  
Manuela Gesell ◽  
Elke Hammer ◽  
Michael Specht ◽  
Wittko Francke ◽  
Frieder Schauer
Keyword(s):  
Acetic Acid ◽  
Carboxylic Acid ◽  
Fission Products ◽  
Paecilomyces Lilacinus ◽  
Proton Nuclear Magnetic Resonance ◽  
Ring Cleavage ◽  
Resonance Spectroscopy ◽  
Muconic Acid ◽  
Initial Oxidation ◽  
Gas Chromatography Mass Spectroscopy

ABSTRACT We examined the pathway by which the fungicide biphenyl is metabolized in the imperfect fungus Paecilomyces lilacinus. The initial oxidation yielded the three monohydroxylated biphenyls. Further hydroxylation occurred on the first and the second aromatic ring systems, resulting in the formation of five di- and trihydroxylated metabolites. The fungus could cleave the aromatic structures, resulting in the transformation of biphenyl viaortho-substituted dihydroxybiphenyl to six-ring fission products. All compounds were characterized by gas chromatography-mass spectroscopy and proton nuclear magnetic resonance spectroscopy. These compounds include 2-hydroxy-4-phenylmuconic acid and 2-hydroxy-4-(4′-hydroxyphenyl)-muconic acid, which were produced from 3,4-dihydroxybiphenyl and further transformed to the corresponding lactones 4-phenyl-2-pyrone-6-carboxylic acid and 4-(4′-hydroxyphenyl)-2-pyrone-6-carboxylic acid, which accumulated in large amounts. Two additional ring cleavage products were identified as (5-oxo-3-phenyl-2,5-dihydrofuran-2-yl)-acetic acid and [5-oxo-3-(4′-hydroxyphenyl)-2,5-dihydrofuran-2-yl]-acetic acid. We found that P. lilacinus has a high transformation capacity for biphenyl, which could explain this organism's tolerance to this fungicide.

Bridged Xanthenes. II. An Intramolecular Cycloaddition Route

1975 ◽  
Vol 53 (14) ◽  
pp. 2054-2063 ◽  
Author(s):  
D.J. Bichan ◽  
Peter Yates
Keyword(s):  
Carboxylic Acid ◽  
Acrylic Acid ◽  
Ethylene Glycol ◽  
Structural Features ◽  
Lead Tetraacetate ◽  
Gambogic Acid ◽  
Similar Treatment ◽  
Intramolecular Cycloaddition ◽  
Naturally Occurring ◽  
Acid Lactone

Oxidation of mesitol (8) with lead tetraacetate in acrylic acid followed by gentle heating gives 6-hydroxy-4,6,7-trimethyl-5-oxobicyclo[2.2.2]oct-7-ene-2-carboxylic acid lactone (13), which is considered to be formed via intramolecular cycloaddition of 6-acryloxy-2,4,6-trimethyl-2,4-cyclohexadienone (11). Similar treatment of 4-methylxanthen-3-o1 (7) gives the corresponding bridged xanthene keto lactone 5. Ketalization of this with ethylene glycol, followed by treatment with methylmagnesium iodide, hydrolysis, and pyrolysis gives the bridged xanthene keto ether 4, which possesses many of the structural features of the nucleus of the naturally occurring coloring matters morellin and gambogic acid.

Biodegradation of carbazole byRalstoniasp. RJGII.123 isolated from a hydrocarbon contaminated soil

2000 ◽  
Vol 46 (3) ◽  
pp. 269-277 ◽  
Author(s):  
Joanne Schneider ◽  
Robert J Grosser ◽  
Koka Jayasimhulu ◽  
Weiling Xue ◽  
Brian Kinkle ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Mass Spectroscopy ◽  
Contaminated Soils ◽  
High Performance ◽  
Coal Gasification ◽  
Ring Cleavage ◽  
Gasification Plant ◽  
Gas Chromatography Mass Spectroscopy ◽  
Hazardous Compounds ◽  
High Resolution Mass Spectroscopy

The use of microorganisms for bioremediation of contaminated soils may be enhanced with an understanding of the pathways involved in their degradation of hazardous compounds. Ralstonia sp. strain RJGII.123 was isolated from soil located at a former coal gasification plant, based on its ability to mineralize carbazole, a three-ring N-heterocyclic pollutant. Experiments were carried out with strain RJGII.123 and14C-carbazole (2 mg/L and 500 mg/L) as the sole organic carbon source. At 15 days, 80% of the 2 mg/L carbazole was recovered as CO2, and <1% remained as undegraded carbazole, while 24% of the 500 mg/L carbazole was recovered as CO2and ~70% remained as undegraded carbazole. Several stable intermediates were formed during this time. These intermediates were separated by high performance liquid chromatography (HPLC) and were characterized using high resolution mass spectroscopy (HR-MS) and gas chromatography - mass spectroscopy (GC-MS). At least 10 ring cleavage products of carbazole degradation were identified; four of these were confirmed as anthranilic acid, indole-2-carboxylic acid, indole-3-carboxylic acid, and (1H)-4-quinolinone by comparison with standards. These data indicate that strain RJGII.123 shares aspects of carbazole degradation with previously described Pseudomonas spp., and may be useful in facilitating the bioremediation of NHA from contaminated soils.Key words: mineralization, biodegradation, N-heterocyclic aromatic hydrocarbons, carbazole.

6H-Dibenzo[b,d]pyrans. I. Synthesis

1975 ◽  
Vol 53 (3) ◽  
pp. 343-349 ◽  
Author(s):  
John P. Devlin
Keyword(s):  
Carboxylic Acid ◽  
Sodium Borohydride ◽  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
Ring Cleavage ◽  
Borohydride Reduction ◽  
Grignard Addition ◽  
Sodium Borohydride Reduction

The preparation of 2′,4′-dihydroxy- and 2′,6′-dihydroxybiphenyl-2-carboxylic acid lactones (3 and 4) is described. Grignard addition to or direct boron trifluoride etherate – sodium borohydride reduction of these lactones yields respectively these 6,6-substituted (e.g. 6) or the 6,6-unsubstituted (13a) 6H-dibenzo[b,d]pyrans. Evidence that the reductive route proceeds without ring cleavage is presented.

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