Oxidative Coupling of Lignans. III. Non-Phenolic Oxidative Coupling of Deoxypodorhizon and Related Compounds

1988 ◽  
Vol 41 (6) ◽  
pp. 897 ◽  
Author(s):  
RC Cambie ◽  
PA Craw ◽  
PS Rutledge ◽  
PD Woodgate
Keyword(s):  
Trifluoroacetic Acid ◽  
Oxidative Coupling ◽  
Phenolic Substances ◽  
Related Compounds

Oxidative coupling of deoxypodorhizon (4) with thallium(III) oxide and trifluoroacetic acid may be controlled to give either deoxyisopodophyllotoxin (14) or isostegane (16). These results and those with related non- phenolic substances indicate that the aromatic substituents of the parent diarylbutane play an important role in determining the outcome of oxidative coupling.

ChemInform Abstract: Oxidative Coupling of Lignans. Part 3. Non-Phenolic Oxidative Coupling of Deoxypodorhizon and Related Compounds.

ChemInform ◽  
1989 ◽  
Vol 20 (3) ◽  
Author(s):  
R. C. CAMBIE ◽  
P. A. CRAW ◽  
P. S. RUTLEDGE ◽  
P. D. WOODGATE
Keyword(s):  
Oxidative Coupling ◽  
Related Compounds

Nucleic acid related compounds. 78. Stereocontrolled syntheses of 6′(E and Z)-halovinyl analogues from uridine-derived vinylsulfones via vinyltin intermediates

1993 ◽  
Vol 71 (2) ◽  
pp. 192-198 ◽  
Author(s):  
Stanislaw F. Wnuk ◽  
Morris J. Robins
Keyword(s):  
Nucleic Acid ◽  
Trifluoroacetic Acid ◽  
Bond Cleavage ◽  
Lead Tetraacetate ◽  
Acetylenic Derivative ◽  
Vinyl Derivative ◽  
High Yields ◽  
Related Compounds

Treatment of the 6′(E)-tosylvinyl homonucleoside 1a with Bu3SnH/AIBN/toluene/Δ gave separable mixtures of 6′-vinylstannanes 2a(E/Z) in high yields. Stereospecific halodestannylations with N-iodosuccinimide, bromine, and N-bromosuccinimide proceeded smoothly to give the 6′(E or Z)-iodo(and bromo) vinyl compounds with retention of configuration. Chlorine or iodobenzene dichloride effected moderately stereoselective chlorodestannylation. Treatment of 2a with NH4F/MeOH/Δ resulted in carbon–tin bond cleavage to give the free vinyl derivative 4a. Aqueous trifluoroacetic acid effected concomitant protiodestannylation and deprotection of 2a to give 4b. Treatment of 2a(E) with lead tetraacetate/acetonitrile and deprotection afforded acetylenic derivative 3b.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: XXXIII. ISOLATION OF ACETOVANILLONE FROM WASTE SULPHITE PULP LIQUOR

1938 ◽  
Vol 16b (2) ◽  
pp. 54-56
Author(s):  
Irene K. Buckland ◽  
George H. Tomlinson II ◽  
Harold Hibbert
Keyword(s):  
Aqueous Alkali ◽  
Phenolic Substances ◽  
Related Compounds ◽  
Resinous Product

Waste sulphite pulp liquor (obtained in the manufacture of a commercial sulphite pulp from soft woods, principally spruce and balsam) on treatment with aqueous alkali gave vanillin, acetovanillone, phenolic substances, and a tarry resinous product. The yield of acetovanillone is about 5.5% of that of the vanillin formed, or about 0.3% calculated on the basis of the lignin present.

Access to Biphenyls by Palladium-Catalyzed Oxidative Coupling of Phenyl Carbamates and Phenols

Synthesis ◽  
2019 ◽  
Vol 51 (16) ◽  
pp. 3060-3076 ◽  
Author(s):  
Nadina Truchan ◽  
Christian Jandl ◽  
Alexander Pöthig ◽  
Stefan Breitenlechner ◽  
Thorsten Bach
Keyword(s):  
Trifluoroacetic Acid ◽  
Oxidative Coupling ◽  
Phenyl Ring ◽  
Cross Coupling ◽  
Ortho Position ◽  
Phenyl Substituent ◽  
Steric Factors ◽  
Palladium Catalyzed ◽  
Carbamate Group

The oxidative cross-coupling of phenols (3 equiv) to various substituted phenyl N,N-diethylcarbamates was explored with a variety of substrates. Pd(OAc)2 was employed as the catalyst (20 mol%) and K2S2O8 as the stoichiometric oxidant in trifluoroacetic acid as the solvent (50 °C, 2 h). Carbamates without or with a substituent on the phenyl ring (Me, Ph, Cl, OMe) underwent the reaction unless the phenyl substituent was too strongly electron withdrawing (CN). Cross-coupling occurred exclusively in the ortho position relative to the carbamate group. The regioselectivity at the phenol (ortho or para to hydroxy) was mainly determined by steric factors. Yields up to 60–70% were achieved for specific carbamate/phenol combinations.

Gold-Catalysis: Reactions of Organogold Compounds with Electrophiles

2010 ◽  
Vol 63 (12) ◽  
pp. 1619 ◽  
Author(s):  
A. Stephen K. Hashmi ◽  
Tanuja Dondeti Ramamurthi ◽  
Matthew H. Todd ◽  
Althea S.-K. Tsang ◽  
Katharina Graf
Keyword(s):  
Trifluoroacetic Acid ◽  
Oxidative Coupling ◽  
Gold Catalysis ◽  
Halogenated Compounds

Different arylgold(i), one alkynylgold(i), and one vinylgold(i) triphenylphosphane complexes were subjected to electrophilic halogenation reagents. With N-chlorosuccinimid, N-bromosuccinimid, and N-iodosuccinimid as well as the Barluenga reagent, selectively halogenated compounds were obtained. Trifluoroacetic acid, as a source of protons, leads to a clean protodeauration. With N-fluorobenzenesulfonimide or Selectfluor, exclusively a homocoupling was observed. For the precursor of the vinylgold(i) complex, a similar oxidative coupling could be induced by gold(iii) chloride. Reactions with silicon or tin electrophiles failed.

Synthesis and structure of a stegane from dimethylmatairesinol

1984 ◽  
Vol 37 (8) ◽  
pp. 1775 ◽  
Author(s):  
RC Cambie ◽  
GR Clark ◽  
PA Craw ◽  
PS Rutledge ◽  
PD Woodgate
Keyword(s):  
Trifluoroacetic Acid ◽  
Oxidative Coupling ◽  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
High Yield ◽  
X Ray Diffraction ◽  
X Ray

Oxidative coupling of dimethylmatairesinol with thallium tristrifluoroacetate (prepared in situ from thallium(III) oxide and trifluoroacetic acid) and boron trifluoride etherate gives a high yield of an isostegane which has been isomerized thermally to a stegane. Stereochemical assignments have been confirmed by X-ray diffraction studies.

REACTIONS OF AMIDES AND RELATED COMPOUNDS: III. N.M.R. INVESTIGATION OF THE PROTONATION OF N,N-DIMETHYLNITROSOAMINE, N,N-DIETHYLNITROSOAMINE, AND N-NITROSOPIPERIDINE

1966 ◽  
Vol 44 (2) ◽  
pp. 105-109 ◽  
Author(s):  
Stephen J. Kuhn ◽  
John S. McIntyre
Keyword(s):  
Sulfuric Acid ◽  
Magnetic Resonance ◽  
Perchloric Acid ◽  
Trifluoroacetic Acid ◽  
Proton Magnetic Resonance ◽  
Acid Solutions ◽  
Concentrated Sulfuric Acid ◽  
Related Compounds ◽  
Equimolar Solution ◽  
Magnetic Resonance Spectra

Protonation of N,N-dimethylnitrosoamine has been investigated by dissolving the nitrosoamine in different acids and recording the proton magnetic resonance spectra of these solutions. Concentrated sulfuric acid, sulfuric acid monohydrate, perchloric acid (72%), trifluoroacetic acid, and fluorosulfuric acid have been used in this study. Only in fluorosulfuric acid near 0 °C and lower was a new signal observed for the protonated nitrosoamine molecule. Integration of the peaks has shown that only one proton is captured by the nitrosoamine. The following structure is suggested for the protonated nitrosoamine.[Formula: see text]The n.m.r. spectra of fluorosulfuric acid solutions of N,N-diethylnitrosoamine and N-nitrosopiperidine also show separate signals for the captured proton.The n.m.r. spectrum of an equimolar solution of N,N-dimethylnitrosoamine, N,N-dimethylformamide, and trifluoroacetic acid in 2-nitropropane indicates that N,N-dimethylnitrosoamine is a weaker base.

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