- Formation of C-S Bond by the Elimination of Perfluorocarboxylic Acid
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Thiirane was readily generated from 2-mercaptoethyl trifluoroacetate or pentafluoropropionate by the intramolecular elimination of the perfluorocarboxylic acid with triethylamine.Alkyl benzyl sulfides were also prepared from benzyl trifluoroacetate or pentafluoropropionate and alkanethiols by the intermolecular elimination of the perfluorocarboxylic acid.
- Kawa, Hajimu,Ishikawa, Nobuo
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- Zirconium-catalysed direct substitution of alcohols: enhancing the selectivity by kinetic analysis
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Kinetic analysis was used as a tool for rational optimization of a catalytic, direct substitution of alcohols to enable the selective formation of unsymmetrical ethers, thioethers, and Friedel-Crafts alkylation products using a moisture-tolerant and commercially available zirconium complex (2 to 8 mol%). Operating in air and in the absence of dehydration techniques, the protocol furnished a variety of products in high yields, including glycosylated alcohols and sterically hindered ethers. In addition, the kinetic studies provided mechanistic insight into the network of parallel transformations that take place in the reaction, and helped to elucidate the nature of the operating catalyst.
- Camaj, David,Carlsson, Robin,Dalla-Santa, Oscar,Lill, Malin,Lundberg, Helena,Margarita, Cristiana,Ramstr?m, Anja,Tu?on, Hernando,Villo, Piret
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p. 7420 - 7430
(2021/11/23)
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- Functionalized graphene oxide as an efficient adsorbent for CO2 capture and support for heterogeneous catalysis
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We have designed new imine-functionalized graphene oxide (IFGO) through post synthetic modifications involving co-condensation of 3-aminopropyltriethoxysilane with graphene oxide basal plane containing hydroxyl and epoxy functional groups, followed by Schiff base condensation reaction with 2,6-diformyl-4-methylphenol and impregnation of copper(ii) to it through covalent attachment (Cu-IFGO). Powder X-ray diffraction, N2 sorption analysis, FT-IR, HR-TEM, FE-SEM and TGA/DTA analysis are employed to characterize the materials. The IFGO material exhibits good CO2 storage capacity of 8.10 mmol g-1 (35.64 wt%) and 2.10 mmol g-1 (9.24 wt%) at 273 K and 298 K temperature, respectively, up to 3 bar pressure, suggesting its potential application in environmental clean-up. Also, Cu-IFGO showed high catalytic activity in microwave-assisted one-pot three-component C-S coupling reactions for a diverse range of aryl halides with thiourea and benzyl bromide in aqueous medium to obtain aryl thioether products (maximum yield 86%), which are derivatives of natural products. Moreover, having imine and hydroxyl groups in functionalized graphene oxide, the grafted Cu(ii) chelated at the graphene oxide surface so strongly that it could not be leached out from the material during the course of the coupling reaction. Thus, it displayed very small decrease in product yield up to the sixth reaction cycle suggesting a sustainable future of this Cu(ii)-grafted catalyst.
- Bhanja, Piyali,Das, Sabuj Kanti,Patra, Astam K.,Bhaumik, Asim
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p. 72055 - 72068
(2016/08/09)
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- An efficient and odorless synthesis of thioethers using 2-[Bis(alkylthio)methylene]-3-oxo-N-o-tolylbutanamides as thiol equivalents
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Using 2-[bis(alkylthio)methylene]-3-oxo-N-o-tolylbutanamides 1 as odorless thiol equivalents, an efficient and odorless synthesis of thioethers has been developed. Promoted by NaOH in EtOH, the cleavage of 1 commences to generate thiolate anions, and the generated thiolate anions then react with halides to give various thioethers in good yield. It is noteworthy that only a very faint odor of thiols can be perceived during both the reaction and the workup. Using 2-[bis(alkylthio)methylene]-3-oxo-N-o-tolylbutanamides as odorless thiol equivalents, an efficient and odorless synthesis of thioethers has been developed. Promoted by NaOH in EtOH, the cleavage of 2-[bis(alkylthio)methylene] -3-oxo-N-o-tolylbutanamides commences to generate thiolate anions, and the generated thiolate anions then react with halides to give various thioethers in good yield. Copyright
- Yu, Haifeng
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p. 367 - 371
(2012/04/23)
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- A new approach to the reduction of sulfoxides to sulfides with 1,3-dithiane in the presence of electrophilic bromine as catalyst
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A new, mild, and novel method is described for the efficient deoxygenation of sulfoxides to their corresponding sulfides with 1,3-dithiane at room temperature in the presence of catalytic amounts of N-bromosuccinimide (NBS), 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO), or Br2 as the source of electrophilic bromine.
- Iranpoor, Nasser,Firouzabadi, Habib,Shaterian, Hamid Reza
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p. 2826 - 2830
(2007/10/03)
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- Deoxygenation of sulfoxides and selenoxides with nickel boride
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The deoxygenations of a variety of acyclic sulfoxides and selenoxides have been reported with nickel boride in THF at 0-5°C in nearly quantitative yields. The deoxygenations are proposed to proceed by an oxidative-addition and reductive-elimination mechanism.
- Khurana, Jitender M.,Ray, Abhijit,Singh, Sarika
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p. 3829 - 3832
(2007/10/03)
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- A simple and efficient method for preparation of unsymmetrical sulfides
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A simple and high efficient method for preparation of unsymmetrical sulfides is described.
- Yin, Jianming,Pidgeon, Charles
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p. 5953 - 5954
(2007/10/03)
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- N-alkyloxycarbonyl-3-aryloxaziridines: Their preparation, structure, and utilization as electrophilic amination reagents
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This paper reports the synthesis of a series of N-protected oxaziridines (N-Moc, Boc, Z or Fmoc) and discusses their ability to deliver their N-alkoxycarbonyl fragment to amines, enolates, sulfur, and phosphorus nucleophiles (electrophilic amination). These oxaziridines are prepared by oxidation of the corresponding imines with oxone or anhydrous MCPBA lithium salt as the source of oxygen. They transfer their N-protected fragment to primary and secondary amines to give protected hydrazines in fair to excelent yield. The nitrogen transfer to free amino acids (in form of their R4N+ salts) is particularly fast, even at low temperature, providing L (or D) N-protected α-hydrazino acids. Enolates are C-aminated to give N-protected α-amino ketones, esters, or amides in modest yield, due to a side aldol reaction of the unreacted enolate with the released benzaldehyde. With tertiary amines (Et3N), sulfides (PhSMe), and phosphines (Ph3P), amination and oxidation proceed in a parallel way; the amount of amination product increases when the temperature is lowered (kinetic control). Some of the factors that can orient the oxaziridine reactivity towards amination or oxidation of nucleophiles are considered.
- Vidal, Joelle,Damestoy, Stephanie,Guy, Laure,Hannachi, Jean-Christophe,Aubry, Andre,Collet, Andre
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p. 1691 - 1709
(2007/10/03)
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- γ-lodothioethers as a source of sulfurcontaining radicals: Reaction with electrophilic olefins
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The reaction of several y-iodothioethers (1) with different electrophilic olefins (2), tributyltin chloride and sodium borohydride in the presence of a catalytic amount of AIBN yielded, after treatment with a saturated aqueous solution of sodium fluoride, a mixture of the expected addition products (3) and the corresponding reduced thioethers (4), which can be easily separated chromatographically. Springer-Verlag Iberica 1996.
- Foubelo, Francisco,Gutierrez, Ana Maria
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p. 280 - 284
(2007/10/03)
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- Chemoselective alkylation of thiols: A detailed investigation of reactions of thiols with halides
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Arylthiols, aralkylthiols and alkane thiols can be readily alkylated by alkyl/aralkyl halides in presence of K2CO3/DMF to yield unsymmetrical sulphides in nearly quantitative yields. 2-Mercaptoethanol gave the thioether chemoselectively.
- Khurana,Sahoo
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p. 1691 - 1702
(2007/10/02)
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- Palladium-Catalyzed Synthesis of Allylic and Benzylic Sulifides from the Corresponding Dithiocarbonates
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Allylic and benzylic sulfides are prepared from O-(2-alkenyl) or S-(2-alkenyl) S-alkyl and O-benzyl S-alkyl dithiocarbonates in the presence of palladium(0)-phosphine complex as a catalyst.
- Lu, Xiyan,Ni, Zhijie
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- THIOALKYLTRIBUTYL- AND THIOALKOXYTRIPHENYLPHOSPHONIUM SALTS: PREPARATION AND APPLICATION TO THE SYNTHESIS OF THIOLESTERS AND UNSYMMETRICAL SULFIDES
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Thioalkoxyphosphonium salts, Ph3PSR(1+)*ClO4(1-) (3) and Bu3PSR(1+)*X(1-) (X=ClO4 and BF4) (5), have been prepared from the corresponding tertiary phosphines and disulfides by simple procedures, which involve (i) constant current electrolysis in acetonitrile in the presence of either HClO4 (for 3) or PhCOOH and LiX (for 5), and (ii) stirring an equimolar mixture of a phosphine, a disulfide, PHCOOH, and LiX in acetonitrile at ambient temperature.For the preparation of 3, which have been reported as useful reagents for the synthesis of unsymmetrical disulfides, the electrochemical method is recomended, while for 5 the latter non-electrochemicl procedure gave better results.Reactions of the phosphonium salts 5 with carboxylic acidsand primary alcohols in benzene at ambient temperature gave thiolesters and unsymmetrical sulfides, respectively, in fair to excellent yields.Keywords - triphenylphosphine; tributylphosphine; disulfide; thioalkoxyphosphonium salt; thiolester; unsymmetrical sulfide
- Ohmori, Hidenobu,Maeda, Hatsuo,Konomoto, Kohichi,Sakai, Kiyoshi,Masui, Masaichiro
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p. 4473 - 4481
(2007/10/02)
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- Chemistry of Amine-Boranes. Part 10. Synthesis of Sulphides from Dithioacetals using Pyridine-Borane in Acid
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The synthesis of sulphides from dithioacetals in trifluoroacetic acid or in dichloromethane in the presence of aluminium chloride with pyridine-borane is described.
- Kikugawa, Yasuo
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p. 609 - 610
(2007/10/02)
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