- Continuous-flow step-economical synthesis of thiuram disulfidesviavisible-light photocatalytic aerobic oxidation
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A continuous-flow photocatalytic synthesis of the industrially important thiuram disulfides has been developed, utilizing O2as the oxidant and Eosin Y as the photoredox catalyst. This highly atom- and step-economical method features much reduced reaction time as well as excellent product yield and purity, making it a sustainable and potentially scalable process for industrial production.
- Xu, Hao-Xing,Zhao, Ze-Run,Patehebieke, Yeersen,Chen, Qian-Qian,Fu, Shun-Guo,Chang, Shuai-Jun,Zhang, Xu-Xu,Zhang, Zhi-Liang,Wang, Xiao
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supporting information
p. 1280 - 1285
(2021/02/26)
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- Photocatalytic H2-Evolution by Homogeneous Molybdenum Sulfide Clusters Supported by Dithiocarbamate Ligands
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Irradiation at 460 nm of [Mo3(μ3-S)(μ2-S2)3(S2CNR2)3]I ([2a]I, R = Me; [2b]I, R = Et; [2c]I, R = iBu; [2d]I, R = CH2C6H5) in a mixed aqueous-polar organic medium with [Ru(bipy)3]2+ as photosensitizer and Et3N as electron donor leads to H2 evolution. Maximum activity (300 turnovers, 3 h) is found with R = iBu in 1:9 H2O:MeCN; diminished activity is attributed to deterioration of [Ru(bipy)3]2+. Monitoring of the photolysis mixture by mass spectrometry suggests transformation of [Mo3(μ3-S)(μ2-S2)3(S2CNR2)3]+ to [Mo3(μ3-S)(μ2-S)3(S2CNR2)3]+ via extrusion of sulfur on a time scale of minutes without accumulation of the intermediate [Mo3S6(S2CNR2)3]+ or [Mo3S5(S2CNR2)3]+ species. Deliberate preparation of [Mo3S4(S2CNEt2)3]+ ([3]+) and treatment with Et2NCS21- yields [Mo3S4(S2CNEt2)4] (4), where the fourth dithiocarbamate ligand bridges one edge of the Mo3 triangle. Photolysis of 4 leads to H2 evolution but at ~25% the level observed for [Mo3S7(S2CNEt2)3]+. Early time monitoring of the photolyses shows that [Mo3S4(S2CNEt2)4] evolves H2 immediately and at constant rate, while [Mo3S7(S2CNEt2)3]+ shows a distinctive incubation prior to a more rapid H2 evolution rate. This observation implies the operation of catalysts of different identity in the two cases. Photolysis solutions of [Mo3S7(S2CNiBu2)3]+ left undisturbed over 24 h deposit the asymmetric Mo6 cluster [(iBu2NCS2)3(μ2-S2)2(μ3-S)Mo3](μ3-S)(μ3-η2,η1-S′,η1-S″-S2)[Mo3(μ2-S)3(μ3-S)(S2CNiBu2)2(μ2-S2CNiBu2)] in crystalline form, suggesting that species with this hexametallic composition and core topology are the probable H2-evolving catalysts in photolyses beginning with [Mo3S7(S2CNR2)3]+. When used as solvent, N,N-dimethylformamide (DMF) suppresses H2-evolution but to a greater degree for [Mo3S4(S2CNEt2)4] than for [Mo3S7(S2CNEt2)3]+. Recrystallization of [Mo3S4(S2CNEt2)4] from DMF affords [Mo3S4(S2CNEt2)4(η1,κO-DMF)] (5), implying that inhibition by DMF arises from competition for a Mo coordination site that is requisite for H2 evolution. Computational assessment of [Mo3S4(S2CNMe2)3]+ following addition of 2H+ and 2e- suggests a Mo(H)-μ2(SH) intermediate as the lowest energy species for H2 elimination. An analogous pathway may be available to the Mo6 cluster via dissociation of one end of the μ2-S2CNR2 ligand, a known hemilabile ligand type, in the [Mo3S4]4+ fragment.
- Fontenot, Patricia R.,Shan, Bing,Wang, Bo,Simpson, Spenser,Ragunathan, Gayathri,Greene, Angelique F.,Obanda, Antony,Hunt, Leigh Anna,Hammer, Nathan I.,Webster, Charles Edwin,Mague, Joel T.,Schmehl, Russell H.,Donahue, James P.
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p. 16458 - 16474
(2019/12/24)
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- A disulphide diisobutylcarbamoylmethyl thiuram method for the preparation of (by machine translation)
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The invention discloses a method for the preparation of diisobutyl thiuram sulfide, its steps are: the two isobutyl amine into solvent, then dropping to the carbon disulfide, reaction after the dipping 0.5-1h, shall be diisobutylcarbamoylmethyl dithio Carbamic reaction liquid; the step (1) the diisobutylcarbamoylmethyl dithiocarbamate is slowly dripped into the reaction solution in a hydrogen peroxide solution, oxidizing reaction temperature rise after the dipping, filtering the reaction liquid after the reaction, the obtained precipitate washing, drying, be disulphide diisobutylcarbamoylmethyl thiuram disulfide. The preparation process of the invention is simple, by controlling the solvent, drop conditions, such as acceleration and dropping sequence, no longer add strong acid and strong alkali, reduce the production cost, reduces the potential safety hazard, less pollution, energy saving and environmental protection, the resulting product quality is good, high yield, the policy requirements of the green chemical States. (by machine translation)
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Paragraph 0003; 0031
(2016/11/21)
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- Reduced graphene oxide as recyclable catalyst for synthesis of Bis(aminothiocarbonyl)disulfides from secondary amines and carbon disulfide
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The reaction of secondary amines with CS2 under mild conditions using reduced graphene oxide (rGO) as a green catalyst was reported, which provided an efficient access to the one-pot synthesis of bis(aminothiocarbonyl) disulfides. The rGO can be recycled at least four times without any loss of catalytic activity. A plausible mechanism was proposed.
- Wang, Meishuang,Song, Xianghai,Ma, Ning
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p. 1233 - 1239
(2014/07/21)
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- Development of an improved method for conversion of thiuram disulfides into N,N-dialkylcarbamoyl halides and derivatives
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A convenient procedure for preparing N,N-disubstituted carbamoyl halides is reported. It consists of two steps: (1) reaction of carbon disulfide and a secondary amine in the presence of a polar organic solvent and oxygen to produce the corresponding tetraalkyl thiuram disulfides and (2) reaction of tetraalkyl thiuram disulfide with a halide in the presence of an aprotic organic solvent to produce the corresponding N,N-disubstituted carbamoyl halide. Copyright Taylor & Francis Group, LLC.
- Adeppa,Rupainwar,Misra, Krishna
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experimental part
p. 285 - 290
(2011/03/20)
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- Combinations for the treatment of fungal infections
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The invention features methods and compositions for treating a patient diagnosed with, or at risk for developing, a fungal infection.
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