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.

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).

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.

Oxidative decarboxylation of the 3-methyl-2-carboxynorbornanes with lead tetraacetate

1976 ◽  
Vol 54 (8) ◽  
pp. 1222-1225 ◽  
Author(s):  
J. B. Stothers ◽  
K. C. Teo
Keyword(s):  
Carboxylic Acids ◽  
Lead Tetraacetate ◽  
Starting Material ◽  
Oxidative Decarboxylation ◽  
Methyl Group

The mixtures of isomeric acetates produced by oxidative decarboxylation of the four 3-methyl-norbornane-2-carboxylic acids with lead tetraacetate in benzene have been characterized. The composition of these products depends primarily on the configuration of the methyl group in the starting material. The results are compared with those found for the Pb(OAc)4 decarboxylation of the norbornane-, bornane-, and 2,3,3-trimethylnorbornane-2-carboxylic acids. The formation of the products is interpreted in terms of competitive cationic and SNi substitution.

scholarly journals The metabolism of 3,5-di-tert.-butylphenyl N-methylcarbamate in insects and by mouse liver enzymes

1971 ◽  
Vol 125 (2) ◽  
pp. 395-400 ◽  
Author(s):  
P. G. C. Douch ◽  
J. N. Smith
Keyword(s):  
Musca Domestica ◽  
Mouse Liver ◽  
Liver Enzymes ◽  
Lucilia Sericata ◽  
Oxidation Products ◽  
Methyl Group ◽  
Tert Butyl ◽  
Costelytra Zealandica

The oxidation of 3,5-di-tert.-butylphenyl N-methylcarbamate (Butacarb) has been studied in the flies Musca domestica and Lucilia sericata, grass grubs Costelytra zealandica and the mouse. In all species eleven oxidation products, which were formed by hydroxylation of the tert.-butyl groups and the N-methyl group, were detected.

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 Degradation of 2,4,6-Trichlorophenol by Phanerochaete chrysosporium: Involvement of Reductive Dechlorination

1998 ◽  
Vol 180 (19) ◽  
pp. 5159-5164 ◽  
Author(s):  
G. Vijay Bhasker Reddy ◽  
Maarten D. Sollewijn Gelpke ◽  
Michael H. Gold
Keyword(s):  
Phanerochaete Chrysosporium ◽  
Reductive Dechlorination ◽  
Oxidation Products ◽  
Ring Cleavage ◽  
Fungal Metabolites ◽  
Subsequent Degradation ◽  
Metabolic Conditions ◽  
The Common ◽  
Dechlorination Reaction

ABSTRACT Under secondary metabolic conditions, the lignin-degrading basidiomycete Phanerochaete chrysosporium mineralizes 2,4,6-trichlorophenol. The pathway for the degradation of 2,4,6-trichlorophenol has been elucidated by the characterization of fungal metabolites and oxidation products generated by purified lignin peroxidase (LiP) and manganese peroxidase (MnP). The multistep pathway is initiated by a LiP- or MnP-catalyzed oxidative dechlorination reaction to produce 2,6-dichloro-1,4-benzoquinone. The quinone is reduced to 2,6-dichloro-1,4-dihydroxybenzene, which is reductively dechlorinated to yield 2-chloro-1,4-dihydroxybenzene. The latter is degraded further by one of two parallel pathways: it either undergoes further reductive dechlorination to yield 1,4-hydroquinone, which isortho-hydroxylated to produce 1,2,4-trihydroxybenzene, or is hydroxylated to yield 5-chloro-1,2,4-trihydroxybenzene, which is reductively dechlorinated to produce the common key metabolite 1,2,4-trihydroxybenzene. Presumably, the latter is ring cleaved with subsequent degradation to CO2. In this pathway, the chlorine at C-4 is oxidatively dechlorinated, whereas the other chlorines are removed by a reductive process in which chlorine is replaced by hydrogen. Apparently, all three chlorine atoms are removed prior to ring cleavage. To our knowledge, this is the first reported example of aromatic reductive dechlorination by a eukaryote.

Sign in / Sign up

Export Citation Format

Share Document