- Continuous photochemical production of high purity linear mercaptan and sulfide compositions
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Continuous photochemical production of high purity linear mercaptan and sulfide-containing compositions.
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Page/Page column 24-25
(2021/11/03)
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- Catalytic Hydrogenation of Thioesters, Thiocarbamates, and Thioamides
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Direct hydrogenation of thioesters with H2 provides a facile and waste-free method to access alcohols and thiols. However, no report of this reaction is documented, possibly because of the incompatibility of the generated thiol with typical hydrogenation catalysts. Here, we report an efficient and selective hydrogenation of thioesters. The reaction is catalyzed by an acridine-based ruthenium complex without additives. Various thioesters were fully hydrogenated to the corresponding alcohols and thiols with excellent tolerance for amide, ester, and carboxylic acid groups. Thiocarbamates and thioamides also undergo hydrogenation under similar conditions, substantially extending the application of hydrogenation of organosulfur compounds.
- Luo, Jie,Rauch, Michael,Avram, Liat,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 21628 - 21633
(2021/01/11)
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- Insight into the Mechanism of Reversible Ring-Opening of 1,3-Benzoxazine with Thiols
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The reversible ring-opening addition and fragmentation reaction of p-cresol-based N-phenylbenzoxazine with aliphatic and aromatic thiols was investigated in solvent-mediated and solvent-free reactions. Independently of the used thiol, N-phenylbenzoxazine and the thiols reacted to equilibrium with comparable amounts of reactants and products in aprotic solvent, whereas in protic solvent almost full conversions were reached. In contrast, thiol reactivity was a crucial factor in solvent-free reactions yielding fast and complete conversions for a more acidic thiol and balanced equilibrium concentrations in case of thiols with high pKa values. The strong influence of thiols with low pKa values emphasizes the relevance of the protonation step in the ring-opening reactions of 1,3-benzoxazines with thiols in absence of solvents where acidity predominates nucleophilicity. The reverse reactions, namely adduct dissociation and benzoxazine recovery, were successfully conducted at elevated temperatures and reduced pressure facilitated by the removal of the formed thiols yielding up to 95% recovered 1,3-benzoxazine. These results provide deeper understanding of the reversible ring-opening reaction mechanism of 1,3-benzoxazine with thiols.
- Urbaniak, Tobias,Soto, Marc,Liebeke, Manuel,Koschek, Katharina
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p. 4050 - 4055
(2017/04/27)
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- NON-FLUORINATED MONOMERS AND POLYMERS FOR SURFACE EFFECT COMPOSITIONS
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The present invention relates to monomers and polymers of Formula (I): where R3 is selected from H or a C1 to C4 alkyl group; Y is selected from O or a substituted or unsubstituted arylene group; A is a linear or branched C1 to C10 alkylene group; w is 0 or 1; v is 0 or 1; y is 0 or 1; X is the residue of a cyclic or acyclic sugar alcohol which is substituted with at least one —R1; —C(O)R1; —(CH2CH2O)n(CH(CH3)CH2O)mR2; —(CH2CH2O)n(CH(CH3)CH2O)mC(O)R1; each n is independently 0 to 20; each m is independently 0 to 20; each R1 is independently a linear or branched alkyl group having 9 to 29 carbons optionally comprising at least 1 unsaturated bond; and each R2 is independently —H, a linear or branched alkyl group having 6 to 30 carbons optionally comprising at least 1 unsaturated bond, or mixtures thereof.
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- Mechanistic Insights into Temperature-Dependent Trithiocarbonate Chain-End Degradation during the RAFT Polymerization of N-Arylmethacrylamides
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Mechanistic insights into trithiocarbonate degradation during the RAFT polymerization of N-arylmethacrylamides are reported. Previous work by our group showed significant RAFT agent degradation during the polymerization of N-arylmethacryloyl sulfonamides at 70 °C. Herein we report the influence of methacrylamide structure on trithiocarbonate degradation during the RAFT polymerizations of N-phenylmethacrylamide (PhMA) and N-benzylmethacrylamide (BnMA) in DMF at 70 and 30 °C. UV-vis spectroscopy revealed trithiocarbonate degradation occurs exclusively after covalent addition of monomer to the RAFT agent, with 60% trithiocarbonate degradation occurring after 12 h during the polymerization of PhMA at 70 °C compared to only 3% degradation measured during the polymerization of BnMA under identical conditions. Small molecule analogues of trithiocarbonate-functional poly(PhMA) and poly(BnMA) were synthesized by single monomer unit insertion and the kinetics and byproducts of degradation investigated by in situ 1H NMR analysis at 70 °C. Trithiocarbonate degradation was ultimately shown to occur by N-phenyl-promoted, N-5 nucleophilic attack on the terminal thiocarbonyl by the ultimate methacrylamide unit.
- Abel, Brooks A.,McCormick, Charles L.
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p. 465 - 474
(2016/02/05)
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- SYNTHETIC METHOD FOR THE PREPARATION OF 1, 2-BENZISOTHIAZOLIN-3-ONE
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The present invention relates to a method for producing a 1,2-benzisothiazolin-3-one compound (I) by reacting a 2-halobenzonitrile compound (II) with a thiol compound (III) to form an intermediate (IV) and subsequently reacting the intermediate (IV) with a halogenation agent in the presence of water to form a reaction mixture (RM), comprising the 1,2-benzisothiazolin-3-one compound (I) and a halide compound (V).
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Paragraph 0277
(2015/12/05)
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- Synthetic method for the preparation of 1,2-Benzisothiazolin-3-one
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The present invention relates to a method for producing a 1,2-benzisothiazolin-3-one compound (I) by reacting a 2-halobenzonitrile compound (II) with a thiol compound (III) to form an intermediate (IV) and subsequently reacting the intermediate (IV) with a halogenation agent in the presence of water to form a reaction mixture (RM), comprising the 1,2-benzisothiazolin-3-one compound (I) and a halide compound (V). R3-SH (III), R3_X1(V),
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-
Paragraph 0164; 0167; 0170
(2015/12/18)
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- 3-(2-aminophenyl)-4-methyl-1,3-thiazole-2(3H)-thione as an ecofriendly sulphur transfer agent to prepare alkanethiols in high yield and high purity
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A new process is described for preparing very pure linear alkanethiols and linear α,ω-alkanedithiols using a sequential alkylation of the title compound, followed by a ring closure to quantitatively give the corresponding 3-methyl[1,3]thiazolo[3,2-a]-[3,1
- Mehdid, Mohammed Amine,Djafri, Ayada,Roussel, Christian,Andreoli, Federico
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experimental part
p. 4634 - 4643
(2010/04/06)
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- Photosensitized electron transfer oxidation of sulfides: A steady-state study
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The photosensitized electron-transfer oxidation of a series of ethyl sulfides RSEt (1, R = C12H25; 2, PhCH2CH 2; 3, PhCH2; 4, PhCMe2; 5, Ph2CH) has been examined in acetonitrile and the product distribution discussed on the basis of the mechanisms proposed. In nitrogen-flushed solutions, cleaved alcohols and alkenes are formed, whereas under oxygen, in reactions that are 10-70 times faster, sulfoxides and cleaved aldehydes and ketones are formed in addition to the afore-mentioned products. Two sensitizers are compared, 9,10-dicyanoanthracene (DCA) and 2,4,6-triphenylpyrylium tetrafluoroborate (TPP+BF4-), the former giving a higher proportion of the sulfoxide, the latter of cleaved carbonyls. The sulfoxidation is due to the contribution of the singlet oxygen path with DCA. Oxidative cleavage, on the other hand, occurs both with DCA and with TPP+ which is known to produce neither singlet oxygen nor the superoxide anion. This process involves deprotonation from the α position of the sulfide radical cation, but the TPP+ results suggest that O2.- is not necessarily involved and non-activated oxygen forms a weak adduct with the radical cation promoting α-hydrogen transfer, particularly with benzylic derivatives. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Bonesi, Sergio M.,Fagnoni, Maurizio,Albini, Angelo
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scheme or table
p. 2612 - 2620
(2009/04/05)
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- Processes for the synthesis of O-desmethylvenlafaxine
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The present invention describes processes for the preparation of O-desmethylvenlafaxine and tridesmethylvenlafaxine, which may be used as an intermediate in preparing O-desmethylvenlafaxine.
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Page/Page column 5
(2008/12/06)
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- Development of a novel benzyl mercaptan as a recyclable odorless substitute of hydrogen sulfide
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2,4,6-Trimethoxybenzyl mercaptan (4) was developed as an odorless substitute of hydrogen sulfide to afford β-mercapto carbonyl compounds in a Michael addition and to convert alkyl bromides into alkanethiols. Detrimethoxybenzylation of the Michael adducts prepared from 4 and α,β-unsaturated esters or ketones was facilely carried out by treatment with a solvent mixture of trifluoroacetic acid and toluene to give β-mercapto carbonyl compounds. Successive alkaline hydrolysis of 2,4,6-trimethoxybenzyl isothiouronium salt, which was obtained as a side product, regenerated 4 accompanying disulfide 8 in good yield. The disulfide 8 was also converted into 4 by reduction with LiAlH4. A similar protocol was applicable to the synthesis of alkanethiols using the S N2 reaction of alkyl bromides. Our method could be complementary to the classical method of using malodorous benzyl mercaptan as a nucleophile and Birch reduction for debenzylation. Georg Thieme Verlag Stuttgart.
- Matoba, Manabu,Kajimoto, Tetsuya,Node, Manabu
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p. 1930 - 1934
(2008/03/27)
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- A novel one pot synthesis of benzyl sulfides: Samarium-induced, benzyl bromide mediated reduction of alkyl thiocyanates and diaryl disulfides in methanol
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A convenient synthesis of benzyl Sulfides by the treatment of alkyl thiocyanates or diaryl disulfides with metallic samarium and benzyl bromide in methanol has been developed.
- Zhan, Zhuang-Ping,Lang, Kai
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p. 443 - 444
(2007/10/03)
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- Oxidation/reduction interconversion of thiols and disulfides using hydrogen and oxygen catalyzed by a rhodium complex
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RhH(PPh3)4 catalyzes reduction of disulfides to thiols by hydrogen and RhH(PPh3)4/1,4- bis(diphenylphosphino)butane (dppb) catalyzes oxidation of thiols to disulfides by oxygen.
- Arisawa, Mieko,Sugata, Chiyoshi,Yamaguchi, Masahiko
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p. 6097 - 6099
(2007/10/03)
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- Rhodium-catalyzed reductive coupling of disulfides and diselenides with alkyl halides, using hydrogen as a reducing agent
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(Chemical Equation Presented) We have established that RhCl(PPh 3)3 catalyzes a reductive coupling of disulfides and diselenides with alkyl halides in the presence of triethylamine using hydrogen as a reducing agent. This reaction serves as a convenient new method to produce unsymmetrical sulfides and selenides from disulfides and diselenides instead of unstable and odoriferous thiols and selenols.
- Ajiki, Kaori,Hirano, Masao,Tanaka, Ken
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p. 4193 - 4195
(2007/10/03)
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- Catalytic synthesis of thiols from alcohols and hydrogen sulfide
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The basic features of the reaction of thiol synthesis from hydrogen sulfide and methanol, n-propanol, n-butanol, or n-dodecanol in the presence of acid-base catalysts was studied. The catalysts with paired surface sites-weak Lewis acid sites and strong base sites-have a low activity but are selective in thiol formation. The catalysts with strong acid sites exhibited a high activity in the conversion of alcohols but were not selective in the formation of thiols. In the presence of proton-donor catalysts, the thiolation of methanol alone took place; other alcohols underwent only dehydration. The thiolation of methanol on various catalysts yielded dimethyl sulfide along with metanethiol; no dialkyl sulfides was produced in the reaction of hydrogen sulfide with higher alcohols. Copyright
- Mashkina
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- Water effects on SmI2 reductions: A novel method for the synthesis of alkyl thiols by SmI2-promoted reductions of sodium alkyl thiosulfates and alkyl thiocyanates
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Water as a cosolvent has significant improving effect on the reductivity of SmI2 in the reduction of sodium alkyl thiosulfates and alkyl thiocyanates. A new method for synthesis of alkyl thiols by SmI 2/THF/H2O system has been developed.
- Zhan, Zhuang-Ping,Lang, Kai,Liu, Feng,Hu, Li-Ming
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p. 3203 - 3208
(2007/10/03)
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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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- Chemoselective protection of thiols versus alcohols and phenols. The Tosvinyl group
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The conjugate addition of aliphatic and aromatic thiols to ethynyl p-tolyl sulphone (tosylacetylene) has been managed to afford Tosvinyl derivatives chemoselectively (in the presence of oxygen nucleophiles) and stereoselectively (isomers Z) in practically quantitative yields. The conditions of choice are: catalytic amounts of Et3N (only 0.5-1.0 mol%), a reaction temperature around 0°C and, for the less acidic thiols, CF3CH2OH or CH3CN/CF3CH2OH as the solvent. Thus, N-Boc-Cys-OMe has been quantitatively protected as its S-Tosvinyl derivative in the presence of N-Boc-Ser-OMe and N-Boc-Tyr-OMe. This novel protecting group is stable to several basic and acidic conditions; its removal is achieved at rt by treatment with an excess of pyrrolidine or at 0°C with alkanethiolate ions.
- Arjona, Odón,Medel, Rocío,Rojas, Jenny,Costa, Anna M.,Vilarrasa, Jaume
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p. 6369 - 6373
(2007/10/03)
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- Hydrophobic, low-loading and alkylated polystyrene-supported sulfonic acid for several organic reactions in water: Remarkable effects of both the polymer structures and loading levels of sulfonic acids
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The development of hydrophobic, low-loading and alkylated polystyrene-supported sulfonic acid for organic reactions was studied. The effects of both the polymer structures and loading levels of the sulfonic acid catalysts were also discussed. Hydrophobicity of the catalyst was considered as key for efficient catalysis.
- Iimura, Shinya,Manabe, Kei,Kobayashi, Shue
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p. 2416 - 2418
(2007/10/03)
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- The mechanism of polarity-reversal catalysis as involved in the radical-chain reduction of alkyl halides using the silane-thiol couple
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The mechanism by which thiols promote the radical-chain reduction of alkyl halides by a variety of simple silanes, such as Et3SiH and Ph3SiH, has been investigated in detail. Kinetic studies of the thiol-catalysed reduction of 1-bromooctane and of 1-chlorooctane by Et3SiH in cyclohexane at 60°C are consistent with a mechanism that involves reversible abstraction of hydrogen by the thiyl radical from the silane, followed by abstraction of halogen from the octyl halide by the resulting triethylsilyl radical and quenching of the derived octyl radical by the thiol to give octane. On the basis of this mechanism, rate constants for abstraction of hydrogen from Et3SiH by the adamantane-1-thiyl radical (kXSH) and for transfer of hydrogen in the reverse direction (KSiH) were determined as 3.2 × 104 M-1 s-1 and 5.2 × 107 M-1 s-1, respectively, at 60°C. The equilibrium constant kXSH/kSiH is thus 6.2 × 10-4 at 60°C and corresponds to ΔrH ≈ ΔrG = +20.4 kJ mol-1 for abstraction of hydrogen from Et3SiH by 1-AdS, implying that the Si-H bond in the silane is stronger by ca. 20 kJ mol-1 than the S-H bond in the alkanethiol. The silanethiol (ButO)3SiSH was found to be a more effective catalyst than 1-AdSH, because kXSH is greater (1.3 × 105 M-1 s-1) while kSiH is very similar (5.1 × 107 M-1 s-1). The value of kXSH/kSiH is now 2.6 × 10-3 at 60°C and thus the S-H bond in this silanethiol is stronger by ca. 4 kJ mol-1 than that in 1-AdSH. The proposed mechanism for alkyl halide reduction is strongly supported by kinetic studies of the thiol-catalysed H/D-exchange between R3SiH/D and XSH/D and the thiol-catalysed racemisation of (S)-ButMePhSiH, radical-chain processes that provide independent confirmation of the values of kXSH derived from octyl bromide reduction. The value of ΔrH determined in this work indicates that abstraction of hydrogen from Et3SiH by an alkanethiyl radical in cyclohexane solvent is ca. 11 kJ mol-1 less endothermic than implied by the difference in the currently-favoured experimental gas-phase dissociation enthalpies for the Et3Si-H and MeS-H bonds.
- Cai, Yudong,Roberts, Brian P.
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p. 1858 - 1868
(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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- β-carboxy sulfonamide ACAT inhibitors
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β-Carboxy sulfonyl compounds of the formula STR1 wherein R1 is aryl, R3 is hydrogen or alkyl, R3 and R4 are hydrogen or alkyl, Y is --O--, --S--, or --NR2 --, and R5 is alkyl or aryl are potent inhibitors of the enzyme acyl CoA:cholesterol acyltransferase (ACAT) and are thus useful for treating hypercholesterolemia and atherosclerosis.
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- Alkylthiopoly (ethylimidazolium) compounds, process for preparing them and their use as biocidal agents
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The present invention relates to new cationic surfactant compounds of formula: STR1 in which: R1 denotes a C12 -C18 alkyl radical; R denotes methyl, ethyl, hydroxyethyl or benzyl; X denotes an inorganic or organic anion; n is between 2 and 15; w equals 0, 1 or 2; the group [C5 H6 N2 R+ ] representing the following structures, taken mixed or separately: STR2 as well as to their use as biocides.
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- Mitomycin derivatives
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Novel mitomycin derivatives are characterized by a substituent on the C6 -methyl group. The mitomycin derivatives exhibit anti-tumor and antibacterial activity and have low toxicity.
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- A Method for the Simultaneous Preparation of Alkyl Isothiocyanates and Thiols
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Aus primaeren Alkylaminen wurden Ethyl-, Butyl-, Isobutyl- und n-Dodecyldithiocarbamate 2 hergestellt.Letztere lassen sich leicht zu den Isothiocyanaten 3 und Thiolen 4 pyrolisieren.Die Massenspektren der Ester sowie deren Pyrolyseprodukte wurden gemessen.
- Blotny, Grzegorz
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p. 1927 - 1932
(2007/10/02)
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- REDUCTION OF SULFONIC ACIDS WITH PHOSPHORUS PENTASULFIDE
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Arene, and alkanesulfonic acids are easily reduced to the corresponding polysulfides R-(S)n-R (n= 2.9 3.3) by treatment with phosphorus pentasulfide.In this reaction, the formation of both P-O-S and P-S-H linkages is considered to be involved in the key step of the reduction.
- Oae, Shigeru,Togo, Hideo
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p. 4701 - 4704
(2007/10/02)
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- Pesticidal compositions containing phosphoric esters and divalent sulphur compounds
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Pesticidal composition comprising: a pesticidal, phosphoric ester the molecule of which has at least one alkyl group of 1 to 3 carbon atoms, 0.05 to 10% of an agent stabilizing the said ester against decomposition by protonisation, together with adjuvants characterized in that the stabilizing agent comprises at least one sulphur compound containing per molecule at least one divalent sulphur atom of which one valence is bonded to an atom chosen from sulphur, carbon, nitrogen, hydrogen, and metals capable of giving a salt, the other valence being bonded to an atom chosen from hydrogen, the carbon atom already noted, a second carbon atom, the nitrogen atom already noted, a second nitrogen atom, the metal atom already noted in the case of a metal of valence greater than one, a second atom of metal and oxygen when the first valence is not attached to an atom of hydrogen, the proportion of sulphur calculated with reference to the weight of the sulphur compound being between 5 and 99%. Process for stabilizing a phosphoric ester of which the molecule possesses at least one alkyl group containing 1 to 3 carbon atoms characterized in that there is added to the phosphoric ester or to a mixture which contains it, 0.05 to 10% calculated on the weight of the phosphoric acid ester of an agent capable of stabilizing the said phosphoric ester against protonisation and comprising at least one sulphur compound such as that defined thereupon.
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- 3-Aryl-2-halothiopropionic acid s-esters
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Novel 3-aryl-2-halothiopropionic acid compounds of the formula STR1 wherein X is chlorine or bromine, R1 is hydrogen, a salt-forming cation, an aliphatic radical or a substituted aliphatic radical wherein the substituent is halogen, haloalkyl, hydroxy, alkoxy, alkoxy-carbonyl or aryl, R2 is hydrogen, halogen or alkyl R3 is hydrogen or alkyl n is an integer from 0 to 3; and R4 is halogen, alkyl, haloalkyl or nitro and wherein the radical R4, when n is 2 or 3, may be the same or different, Are outstandingly effective herbicides, exhibiting particularly selective action.
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