- Cu-mediated: vs. Cu-free selective borylation of aryl alkyl sulfones
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A Cu-catalysed borylation of aryl alkyl sulfones was developed for the high yield synthesis of versatile arylboronic esters using a readily prepared NHC-Cu catalyst. In addition, the selective cleavage of either alkyl(C)-sulfonyl or aryl(C)-sulfonyl bonds
- Hu, Jiefeng,Huang, Mingming,Marder, Todd B.,Radius, Udo,Tang, Man,Westcott, Stephen A.
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p. 395 - 398
(2022/01/19)
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- Photoisomerization of azobenzene-substituted alkanethiolates on Au(111) substrates in the context of work function variation: The effect of structure and packing density
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Photoisomerization of a series of custom-designed, azobenzene-substituted alkanethiolate (AT) self-assembled monolayers (SAMs) on Au(111) substrates was studied in the context of work function variation, using Kelvin probe measurements as a transduction technique. These SAMs featured variable packing density (by ～14%; due to the odd-even effects) and, as an option, were additionally decorated with the electron donating/withdrawing -CH3 and -CF3 tail group, respectively, which induce additional dipole moments. The efficiency of photoisomerization and the respective extent of work function variation (ΔΦ) were found to be quite low and independent of the packing density in the SAMs, within the given odd-even packing density variation. They could only be increased, up to ca. 40 meV for ΔΦ, by mixing the azobenzene-substituted ATs with shorter "matrix" molecules, which were introduced for a partial release of the sterical constraints. The ΔΦ values for the SAMs decorated with the -CH3 and -CF3 tail groups were found to be lower than those for the monolayers without such a decoration, which correlated well with the theoretical estimates for the change of the dipole moment of the relevant molecules upon the photoisomerization.
- Schuster, Swen,Füser, Matthias,Asyuda, Andika,Cyganik, Piotr,Terfort, Andreas,Zharnikov, Michael
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p. 9098 - 9105
(2019/05/21)
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- Mo-Based Oxidizers as Powerful Tools for the Synthesis of Thia- and Selenaheterocycles
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A highly efficient synthetic protocol for the synthesis of thia- and selenaheterocycles has been developed. By employing a MoCl5-mediated intramolecular dehydrogenative coupling reaction, a broad variety of structural motifs was isolated in yields up to 94 %. The electrophilic key transformation is tolerated by several labile moieties like halides and tertiary alkyl groups. Due to the use of disulfide or diselenide precursors, a high atom efficiency was achieved.
- Franzmann, Peter,Beil, Sebastian B.,Schollmeyer, Dieter,Waldvogel, Siegfried R.
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supporting information
p. 1936 - 1940
(2019/01/14)
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- Substrate and Catalyst Effects in the Enantioselective Copper-Catalysed C–H Insertion Reactions of α-Diazo-β-oxo Sulfones
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Excellent enantioselectivities of up to 98 % ee are achieved by employing the copper-bis(oxazoline)-NaBARF catalyst system in the C–H insertion reactions of α-diazo-β-oxo sulfones. The influence of variation of the bis(oxazoline) ligand, copper salt, additive and substrate on both the efficiency and the enantioselectivities of these intramolecular C–H insertion reactions has been explored. Optimum enantioselectivities are achieved with phenyl and diphenyl ligands across the substrate series.
- Shiely, Amy E.,Clarke, Leslie-Ann,Flynn, Christopher J.,Buckley, Aoife M.,Ford, Alan,Lawrence, Simon E.,Maguire, Anita R.
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supporting information
p. 2277 - 2289
(2018/06/04)
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- Two-step three-component process for one-pot synthesis of 8-alkylmercaptocaffeine derivatives
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A highly efficient, odourless and two-step three-component process for one-pot synthesis of some 8-alkylmercaptocaffeine derivatives has been described. The catalyst-free three-component reaction of alkyl bromides, thiourea, and 8-bromocaffeine gave 8-alkylmercaptocaffeine products in excellent to quantitative yields. In addition, the impact of parameters on sample reaction is discussed.
- Rad, M. N. Soltani,Maghsoudi
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p. 70335 - 70342
(2016/08/06)
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- A novel C-5′ substituted cinchona alkaloid-derived catalyst promotes additions of alkyl thiols to nitroolefins with excellent enantioselectivity
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A new bifunctional C-5′ substituted cinchona alkaloid-based catalyst promotes the first highly enantioselective additions of alkyl thiols to nitrostyrenes. The Royal Society of Chemistry 2012.
- Palacio, Carole,Connon, Stephen J.
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supporting information; experimental part
p. 2849 - 2851
(2012/03/27)
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- Inhibition of monoamine oxidase by 8-[(phenylethyl)sulfanyl]caffeine analogues
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In a previous study we have investigated the monoamine oxidase (MAO) inhibitory properties of a series of 8-sulfanylcaffeine analogues. Among the compounds studied, 8-[(phenylethyl)sulfanyl]caffeine (IC50 = 0.223 μM) was found to be a particularly potent inhibitor of the type B MAO isoform. In an attempt to discover potent MAO inhibitors and to further examine the structure-activity relationships (SAR) of MAO inhibition by 8-sulfanylcaffeine analogues, in the present study a series of 8-[(phenylethyl)sulfanyl]caffeine analogues were synthesized and evaluated as inhibitors of human MAO-A and -B. The results document that substitution on C3 and C4 of the phenyl ring with alkyl groups and halogens yields 8-[(phenylethyl)sulfanyl]caffeine analogues which are potent and selective MAO-B inhibitors with IC50 values ranging from 0.017 to 0.125 μM. The MAO inhibitory properties of a series of 8-sulfinylcaffeine analogues were also examined. The results show that, compared to the corresponding 8-sulfanylcaffeine analogues, the 8-sulfinylcaffeins are weaker MAO-B inhibitors. Both the 8-sulfanylcaffeine and 8-sulfinylcaffeine analogues were found to be weak MAO-A inhibitors. This study also reports the MAO inhibition properties of selected 8-[(phenylpropyl)sulfanyl]caffeine analogues.
- Mostert, Samantha,Mentz, Wayne,Petzer, Anél,Bergh, Jacobus J.,Petzer, Jacobus P.
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p. 7040 - 7050
(2013/01/15)
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- Hydrophobic polymer-supported catalyst for organic reactions in water: Acid-catalyzed hydrolysis of thioesters and transprotection of thiols
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(Matrix presented) A hydrophobic polystyrene-supported sulfonic acid was found to be effective for hydrolysis of thioesters in pure water. It was revealed that the catalyst was much superior to other Bronsted acid catalysts. Transprotection of thiols from thioesters to thioethers has been successfully performed in water using this catalytic system.
- Iimura, Shinya,Manabe, Kei,Kobayashi, Shu
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p. 101 - 103
(2007/10/03)
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- Synthesis of N-glyoxyl prolyl and pipecolyl amides and thioesters and evaluation of their in vitro and in vivo nerve regenerative effects
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The recent discovery that small molecule ligands for the peptidyl-prolyl isomerase (PPIase) FKBP12 possess powerful neuroprotective and neuroregenerative properties in vitro and in vivo suggests therapeutic utility for such compounds in neurodegenerative disease. The neurotrophic effects of these compounds are independent of the immunosuppressive pathways by which drugs such as FK506 and rapamycin operate. Previous work by ourselves and other groups exploring the structure-activity relationships (SAR) of small molecules that mimic only the FKBP binding domain portion of FK506 has focused on esters of proline and pipecolic acid. We have explored amide and thioester analogues of these earlier structures and found that they too are extremely potent in promoting recovery of lesioned dopaminergic pathways in a mouse model of Parkinson's disease. Several compounds were shown to be highly effective upon oral administration after lesioning of the dopaminergic pathway, providing further evidence of the potential clinical utility of a variety of structural classes of FKBP12 ligands.
- Hamilton, Gregory S.,Wu, Yong-Qian,Limburg, David C.,Wilkinson, Douglas E.,Vaal, Mark J.,Li, Jia-He,Thomas, Christine,Huang, Wei,Sauer, Hansjorg,Ross, Douglas T.,Soni, Raj,Chen, Yi,Guo, Hongshi,Howorth, Pamela,Valentine, Heather,Liang, Shi,Spicer, Dawn,Fuller, Mike,Steiner, Joseph P.
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p. 3549 - 3557
(2007/10/03)
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- Cleavage of a p-cyanobenzyl group from protected alcohols, amines, and thiols using triethylgermyl sodium
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Alcohols, amines, and thiols protected with a p-cyanobenzyl group can be easily and quantitatively deprotected using triethylgermyl sodium under mild conditions.
- Yokohama, Yasuo,Takizawa, Shuichi,Nanjo, Masato,Mochida, Kunio
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p. 1032 - 1033
(2007/10/03)
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- Convenient cleavage of water-insoluble allylic substrates in the presence of per(2,6-di-O-methyl)-β-cyclodextrin
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The removal of allylic protecting groups promoted by a water soluble palladium complex of the trisulfonated triphenylphosphine is achieved in very high yields (95-100%) on a wide range of water-insoluble substrates in a genuine two-phase system by using the per(2,6-di-O-methyl)-β-cyclodextrin as inverse phase transfer catalyst. The catalytic activities were up to 1000 times higher than those observed without cyclodextrin.
- Widehem, Rodrigue,Lacroix, Thibaut,Bricout, Herve,Monflier, Eric
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p. 722 - 724
(2007/10/03)
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- Thiazolidinedione hypoglycemic agents
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Hypoglycemic thiazolidine-2,4-dione derivatives of the formula STR1 wherein the dotted line represents a bond or no bond; A and B are each independently CH or N, with the proviso that when A or B is N, the other is CH; X is S, SO, SO2, CH2, CHOH or CO; n is 0 or 1; Y is CHR1 or NR2, with the proviso that when n is 1 and Y is NR2, X is SO2 or CO; Z is CHR3, CH2 CH2, CH=CH, STR2 OCH2, SCH2, SOCH2 or SO2 CH2 ; R, R1, R2 and R3 are each independently hydrogen or methyl; and X1 and X2 are each independently hydrogen, methyl, trifluoromethyl, phenyl, benzyl, hydroxy, methoxy, phenoxy, benzyloxy, bromo, chloro or fluoro; a pharmaceutically-acceptable cationic salt thereof; or a pharmaceutically-acceptable acid addition salt thereof when A or B is N.
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- ALKYLAMIDE DERIVATIVES WITH H2-RECEPTOR ANTAGONISTIC AND CYTOPROTECTIVE ACTION
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Alkylamide derivatives having the formula, These compounds have a strong antiulcer action depend on histamine H 2-receptor antagonistic action and a cytoprotective action upon gastric mucous membrance.
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- Nucleophilic and Electrophilic Mercaptanylations via 2-(Trimethylsilyl)ethanethiol-Derived Reagents
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2-(Trimethylsilyl)ethanethiol reacts with carboxylic acids, alkyl halides, epoxides, and enones to provide acyl- and alkyl-substituted 2-(trimethylsilyl)ethyl sulfides.Electrophilic mercaptanylation is effected by a thiol-sulfonate reagent derived from 2-(trimethylsilyl)ethanethiol.
- Anderson, M.B.,Ranasinghe, M.G.,Palmer, J.T.,Fuchs, P.L.
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p. 3125 - 3127
(2007/10/02)
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