- Mild Darzens Annulations for the Assembly of Trifluoromethylthiolated (SCF3) Aziridine and Cyclopropane Structures
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We report mild new annulation approaches to trisubstituted trifluoromethylthiolated (SCF3) aziridines and cyclopropanes via Darzens inspired protocols. The products of these anionic annulations, rarely studied previously, possess attractive features rendering them valuable building blocks for synthesis platforms. In this study, trisubstituted acetophenone nucleophiles bearing SCF3 and bromine substituents in their α position were shown to undergo [2 + 1] annulations with vinyl ketones and tosyl-protected imines under mild reaction conditions.
- Delost, Michael D.,Njardarson, Jon T.
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supporting information
p. 6121 - 6125
(2021/08/16)
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- METHOD FOR MAKING BIARYL COMPOUNDS, COMPOUNDS MADE BY THE METHOD, AND METHOD FOR THEIR USE
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Certain disclosed embodiments of the present invention concern a method for making biaryl compounds by combining a diene with a dienophile under reaction conditions that facilitate a Diels-Alder reaction. Certain embodiments are particularly directed to making a tetra-ortho-substituted biaryl compounds. The disclosed method may involve using novel dienes, dienophiles, or both. Similarly, certain of the biaryl compounds are novel compounds too. Additional disclosed embodiments concern a method for making useful compounds by first making a Diels-Alder adduct. The Diels-Alder adduct is then further modified or coupled to other compounds. The method can be used to make carbazoles, such as Siamenol. Disclosed biaryl compounds are useful for a number of applications, such as pharmacophores and organocatalysts.
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Page/Page column 46; 177
(2009/01/23)
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- Diels - Alder approach for the construction of halogenated, o-nitro biaryl templates and application to the total synthesis of the anti-HIV agent siamenol
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(Chemical Equation Presented) A rapid Diels - Alder approach to halogenated biaryl templates is described. These biaryl templates are available in two steps from the corresponding aromatic aldehydes. The scope of subsequent Suzuki couplings on the biaryl chlorides is explored. Good tolerance for both electron-donating and electron-withdrawing groups in the coupling process can be achieved. Further functionalization of the biaryl templates is described. Hydrogenation of the nitro moiety with concomitant removal of the benzyl ether yields the o-anilino, o-phenolic polyaryls. Selective reduction of the nitro group can be accomplished. Alternatively, the benzyl ether can be selectively removed under Lewis acidic conditions. The utilization of the Diels - Alder adducts for the synthesis of a series of chlorinated carbazoles via the Cadogan cyclization is also demonstrated. Finally, application of this technology to the total synthesis of siamenol, an anti-HIV agent, is reported.
- Naffziger, Michael R.,Ashburn, Bradley O.,Perkins, Johanna R.,Carter, Rich G.
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p. 9857 - 9865
(2008/04/05)
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- Polyaza Heterocycles. Part 2. Nucleophilic Substitution of Halogens in Halogenoquinoxalinocinnolines
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10-Chloroquinoxalinocinnoline readily undergoes methoxydechlorination when treated with sodium methoxide.The 1-, 2-, 3-, 4- and 9-chloro isomers are unreactive towards this reagent, but the 9,10-dichloro derivative undergoes substitution of both chlorines (the 10-position being much the more reactive).The 9- and 10-bromo analogues are both unreactive towards sodium methoxide, but the 9- and 10-fluoro analogues are both highly reactive, to the extent that it has not been possible even to isolate the 10-fluoro compound.Routes to 9- and 10-piperidinoquinoxalinocinnolines are described.
- Ahmad, Arshad,Dunbar, Linda J.,Green, Iain G.,Harvey, Ian W.,Shepherd, Thomas,et al.
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p. 2751 - 2758
(2007/10/02)
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- Compounds interacting with tubulin: Part I: Synthesis of ortho-ortho' substituted phenylpyrroles with free or restricted rotation.
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The synthesis of ortho-ortho' substituted phenylpyrroles that are susceptible to isomerization of the biaryl type (atropisomerism) was performed using a Michael addition of isocyanoacetates with nitrostyrenes.Atropisomerism in phenylpyrroles 14 and 15 was studied by means of 1H NMR spectroscopy using chiral lanthanide shift reagents (LSR*).In the case of chiral phenylpyrrole 21, an evaluation of the interconversion parameters between diastereomers (k, ΔGT*) was attempted. - - - tubulin / phenylpyrrole / atropisomers / chiral shift reagents
- Alazard, JP.,Boye, O.,Gillet, B.,Guenard, D.,Beloeil, JC.,Thal, C.
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p. 779 - 787
(2007/10/02)
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- BIOMIMETIC MODELS OF CYTOCHROME P-450. SYNTHESIS AND CATALYTIC ACTIVITY OF Mn-PORPHYRINS BEARING COVALENTLY ATTACHED AXIAL LIGANDS
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A description is presented of the synthesis of Mn(III)-tetraarylporphyrins 4 and 5 in which a pyridine axial ligand is connected, through a flexible chain of linearly disposed 9 and 14 atoms, to the tetra(2,6-dichlorophenyl)porphyrin, 6, structure, which is particulary resistant to oxidative degradation.In 4a and 4b the chain is bonded to the porphyrin skeleton through an amido bond in the meta position of a meso-phenyl ring.These Mn(III)-porphyrins proved to be catalytically even more efficient than 6 in the HOCl alkene epoxidations carried out under CH2Cl2-H2O two-phase conditions, at pH 10.5 and in the absence of a phase-transfer catalyst.The chemical stability and catalytic activity of 4a and 4b are lowered in alkene epoxidations promoted by 30percent-H2O2 in the presence of benzoic acid.Mn(III)-porphyrins 5a and 5b, in which one out of eight chorine atoms of 6 has been replaced by the amido group bearing the flexible chain, were less stable with respect to 4a and 4b in epoxidations promoted by either HOCl or 30percent-H2O2.Coordiantion of anchored pyridine and factors ruling catalytic efficiency and chemical stability of catalysts 4 and 5 are also examined.
- Banfi, Stefano,Montanari, Fernando,Quici, Silvio
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p. 435 - 441
(2007/10/02)
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