- Photocatalytic C-O Bond Cleavage of Alcohols Using Xanthate Salts
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The homolytic cleavage of C-O bonds to afford alkyl radicals is an attractive yet challenging transformation in organic synthesis. Herein we describe a photocatalyzed deoxygenative C-C coupling reaction of xanthate salts, which can be easily prepared from the corresponding alcohols. The key to the success of this strategy is the low oxidation potential of the xanthate salt and the use of an appropriate phosphine to accelerate the desulfurative release of carbonyl sulfide.
- Nanjo, Takeshi,Matsugasako, Tatsuki,Maruo, Yuri,Takemoto, Yoshiji
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p. 359 - 363
(2022/01/15)
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- Activation of C-C Bonds via σ-Bond Metathesis: Hydroborenium-Catalyzed Hydrogenolysis of Cyclopropanes
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High-valent transition metal or main group complex mediated σ-bond metathesis plays an important role in the activation of covalent H-E bonds. However, its involvement in the activation of C-C bonds has remained elusive. Here we describe direct hydroboration of the C-C bonds of cyclopropanes by a hydroborenium complex. Our mechanism study suggests this reaction operates through a σ-bond metathesis pathway. With this hydroborenium complex as a catalyst, hydrogenolysis of unfunctionalized cyclopropanes was achieved, which is unprecedented for homogeneous catalysts and provides an unconventional approach for C-C bond functionalization in the absence of metals.
- Su, Bo,Li, Yawei,Li, Zhen Hua,Hou, Jun-Li,Wang, Huadong
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supporting information
p. 4159 - 4163
(2020/04/10)
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- Synthesis method of p-bromo-linear alkylbenzene
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The invention belongs to the technical field of fine chemical industry, and in particular discloses a clean and efficient synthetic process technology of p-bromo-linear alkylbenzene. Paradibromobenzene and linear chain 1-haloalkane are added into an organic solvent, and reaction is conducted under the action of a catalyst ferric acetylacetonate and an activating agent consisting of zinc halide and magnesium powder to obtain the p-bromo-linear alkylbenzene. A paradibromobenzene single coupling technology is adopted, so production of ortho/meta isomers which are difficult to separate is avoided from the source; a Grignard reagent, which is instable to water and air, or an expensive boric acid reagent intermediate is not used, so that the production cost is reduced; a one-pot reaction technology is adopted, so that operation is simplified and good industrial application value is achieved.
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Paragraph 0035-0047
(2017/08/25)
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- N-aryl thienyl-, furyl-, and pyrrolyl-sulfonamides and derivatives thereof that modulate the activity of endothelin
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Thienyl-, furyl- and pyrrolyl-sulfonamides and methods for modulating or altering the activity of the endothelin family of peptides are provided. In particular, N-(isoxazolyl)thienylsulfonamides, N-(isoxazolyl)furylsulfonamides and N-(isoxazolyl)pyrrolylsulfonamides and methods using these sulfonamides for inhibiting the binding of an endothelin peptide to an endothelin receptor by contacting the receptor with the sulfonamide are provided. Methods for treating endothelin-mediated disorders by administering effective amounts of one or more of these sulfonamides or prodrugs thereof that inhibit or increase the activity of endothelin are also provided.
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Page column 80
(2010/01/30)
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- Biphenylsulfonamides and derivatives thereof that modulate the activity of endothelin
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Biphenylsulfonamides and methods for modulating or altering the activity of the endothelin family of peptides are provided. In particular, bicyclic or tricyclic carbon or heterocyclic ring biphenylsulfonamides and methods using these sulfonamides for inhibiting the binding of an endothelin peptide to an endothelin receptor by contacting the receptor with the sulfonamide are provided. Methods for treating endothelin-mediated disorders by administering effective amounts of one or more of these sulfonamides or prodrugs thereof that inhibit or increase the activity of endothelin are also provided.
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- Discotic liquid crystals of transition metal complexes, 31: Establishment of mesomorphism and thermochromism of bis[1,2-bis(4-n-alkoxyphenyl)ethane-1,2-dithiolene]nickel complexes
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Two series of bis[1,2-bis(4-n-alkylphenyl)ethane-1,2-dithiolene]nickel, Cn-Ni (n= 1-12), and bis[1,2-bis(4-n-alkoxyphenyl)ethane-1,2-dithiolene]nickel, CnO-Ni(n = 1-12, 14, 16, 18), have been synthesized. Their mesomorphism, thermochromism, supramolecular structures and π-acceptor property have been investigated by using different scanning calorimetry, polarizing microscopy, temperature-dependent X-ray diffraction technique, electronic spectroscopy and cyclic voltammetry. From the X-ray diffraction and electronic spectral results, it was established that the CnO-Ni complexes for n ≤ 10 exhibit two differently colored discotic lamellar (DL) mesophases whereas none of the Cn-Ni complexes has a mesophase, and that the thermochromism (brown→green) is attributable to a slow transformation from the Ni-Ni bonded dimers to the Ni-S bonded dimers.
- Horie,Takagi,Hasebe,Ozawa,Ohta
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p. 1063 - 1071
(2007/10/03)
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- THIENYL-, FURYL- AND PYRROLYL SULFONAMIDES AND DERIVATIVES THEREOF THAT MODULATE THE ACTIVITY OF ENDOTHELIN
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Thienyl-, furyl-and pyrrolyl-sulfonamides and methods for modulating or altering the activity of the endothelin family of peptides are provided. In particular, N-(isoxazolyl)thienylsulfonamides, N-(isoxazolyl) furylsulfonamides and N-(isoxazolyl)pyrrolylsulfonamides and methods using these sulfonamides for inhibiting the binding of an endothelin peptide to an endothelin receptor by contacting the receptor with the sulfonamide are provided. Methods for treating endothelin-mediated disorders by administering effective amounts of one or more of these sulfonamides or prodrugs thereof that inhibit or increase the activity of endothelin are also provided.
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- SULFONAMIDES AND DERIVATIVES THEREOF THAT MODULATE THE ACTIVITY OF ENDOTHELIN
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Sulfonamides and methods using these sulfonamides for inhibiting the binding of an endothelin peptide to an endothelin receptor by contacting the receptor with the sulfonamide are provided. Methods for treating endothelin-mediated disorders by administering effective amounts of one or more of these sulfonamides or prodrugs thereof that inhibit or increase the activity of endothelin are also provided. The sulfonamides have formula I: STR1 in which Ar 1 is a 3-or 5-isoxazolyl and Ar. sup.2 is selected from among alkyl, including straight and branched chains, aromatic rings, fused aromatic rings and heterocyclic rings, including 5-membered heterocycles with one, two or more heteroatoms and fused ring analogs thereof and 6-membered rings with one, two or more heteroatoms and fused ring analogs thereof. Ar 2 is preferably thiophenyl, furyl, pyrrolyl, naphthyl, and phenyl. Compounds in which Ar. sup.1 is a 4-halo-substituted isoxazole are more active than the corresponding alkyl-substituted compound and compounds in which Ar 1 is substituted at this position with a higher alkyl tend to exhibit greater affinity for ET B receptors than the corresponding lower alkyl-substituted compound.
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- Synthesis of Mesogenic Compounds, Catalyzed by Metal Complexes. I. Monoalkylation and Monoarylation of 1,4-Dibromobenzene in the Synthesis of 4-n-Alkyl- and 4-n-Alkoxy-4'-Cyanobiphenyls Catalyzed by Palladium
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New methods of synthesis of mesomorphic 4-n-alkyl- and 4-n-alkoxy-4'-cyanobiphenyls are developed, based on the palladium catalyzed highly selective reactions of 1,4-dibromobenzene with alkyl and aryl Grignard reagents.
- Bumagin, N. A.,Luzikova, E. V.,Beletskaya, I. P.
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p. 1480 - 1486
(2007/10/03)
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- Synthesis and Liquid Crystal Behaviour of Further 4,4"-Disubstituted 2'-Fluoro-1,1':4',1"-Terphenyls
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Further to earlier work on the liquid crystal properties of fluoro-1,1':4',1"-terphenyls we have now extended this series to include terminally fluoro- and cyano-substituted 2'-fluoro-1,1':4',1"-terphenyls, chiral 2'-fluoro-1,1':4',1"-terphenyls, and esters derived from 2'-fluoro-1,1':4',1"-terphenyls and incorporating the alkylcyclobutyl group.The preparations and transition temperatures for these series of compounds are presented and their transition temperatures and mesophase types are discussed.An interesting result from this work was the appearence of an S*C phase for one chiral homologue and of SC phases for the esters incorporating the alkylcyclobutyl group.The SC formation is attributed to the presence of the fluoro-substituent.Keywords: terphenyls, fluoroterphenyls, smectic C phases, cyclobutyl esters.
- Chan, L. K. M.,Gray, G. W.,Lacey, D.,Toyne, K. J.
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p. 209 - 240
(2007/10/02)
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- Relative Conjugative Abilities of Three-Membered Ring Heterocycles with Benzene Based on 13C and 15N NMR
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The conjugative ability of various three-membered rings with benzene was investigated by observing the sensitivity of β-carbon 13C chemical shifts to para substituents.These Hammett ρ values were 2.0, 1.5, 1.0, and 0.9 ppm for arylcyclopropanes, N-methyl-2-arylaziridines, phenyloxiranes, and N,N-dimethyl-2-arylaziridinium fluorosulfonates, respectively.These values were intermediate to ones for para-substituted styrenes (6.5 ppm) and ethylbenzenes (-0.9 ppm), model compounds which were taken to represent extremes of conjugative ability.Similar results were found for 15N chemical shifts of trans-3-aryl-oxaziridines, which had a slope of 2.1 ppm, intermediate to those for benzylimines (20.2 ppm) and benzylamines (-1.3 ppm).The order of conjugative ability, which decreases with increasing electronegativity of the hetero group, could not be explained by hybridization changes based on comparing open chain analoques with the above compounds or by conformational factors.The trend can, however, be interpreted qualitatively by perturbation theory which shows that more electronegative hetero groups decrease the extent of interaction between aryl-? and cyclopropane orbitals as well as cross ring conjugation.
- Crist, DeLanson R.,Jordan, Guy J.,Moore, Donald W.,Hashmall, Joseph A.,Borsetti, Arnold P.,Turujman, Saleh A.
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p. 4136 - 4142
(2007/10/02)
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- Preparation and Properties of Tertiary p-Alkylarylphosphines containing Straight-chain Alkyl Groups
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A series of tris(p-alkylaryl)phosphines with straight-chain alkyl groups, P(p-C6H4-CnH2n+1)3 where n=2-9, have been prepared by reaction of phosphorus trichloride with the Grignard reagent derived from the corresponding p-bromoalkylbenzene.When n=2 and 3 the phosphines are crystalline solids, but for n>3 they are viscous oils up to n=9, which is a waxy solid.The phosphines have been characterised by microanalysis, and i.r., 1H and 31P n.m.r., and mass spectrometry.The p-substituted-arylphosphines are more sensitive than triphenylphosphine to air; aerial oxidation converts them exclusively into the corresponding phosphine oxides, in contrast to trialkylphosphines which are oxidised to a complex mixture of products.The complexing ability of the new phosphines (PAr3) is demonstrated by their ready displacement of 1,5-cyclo-octadiene (cod) from (M=Pd and Pt) to yield trans- and cis-, respectively.
- Franks, Stephen,Hartley, Frank R.
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p. 2233 - 2237
(2007/10/02)
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