137-26-8 Usage
Uses
1. Used in Agriculture:
Tetramethylthiuram Disulfide is used as a protective fungicide of broad spectrum for the control of powdery mildew, smut, and rice seedlings damping-off of cereal crops. It is also used for some fruit trees and vegetable diseases, as well as a seed disinfectant and an ectoparasiticide.
2. Used in Rubber Industry:
Tetramethylthiuram Disulfide is used as a super accelerator of natural rubber, synthetic rubber, and latex. It is also used as a vulcanizer, a late effect promoter of natural rubber, butadiene rubber, styrene-butadiene rubber, and polyisoprene rubber. It is suitable for the manufacture of cables, wires, tires, and other rubber products.
3. Used as a Pesticide:
Tetramethylthiuram Disulfide is used for pest control of rice, wheat, tobacco, sugar beet, grapes, and other crops, as well as for seed dressing and soil treatment.
4. Used as a Lubricant Additive:
Tetramethylthiuram Disulfide is used as an additive in the blending of lubricant oils.
5. Used as a Wood Preservative:
Tetramethylthiuram Disulfide is used as a preservative for wood.
6. Used in Antiseptic Sprays:
Tetramethylthiuram Disulfide is used in antiseptic sprays for its fungicidal and bactericidal properties.
7. Used as an Antioxidant:
Tetramethylthiuram Disulfide is used as an antioxidant in polyolefin plastics.
8. Used as a Pepetizing Agent:
Tetramethylthiuram Disulfide is used as a peptizing agent in polysulphide elastomers.
9. Used in Soaps and Rodent Repellents:
Tetramethylthiuram Disulfide is used as a bacteriostat in soap and as a rodent repellent.
10. Used as a Disinfectant:
Tetramethylthiuram Disulfide is used as a disinfectant for nuts, fruits, and mushrooms.
11. Used in the Treatment of Human Scabies:
Tetramethylthiuram Disulfide has been used in the treatment of human scabies.
12. Used as a Sunscreen:
Tetramethylthiuram Disulfide has been used as a sunscreen.
13. Used as a Bactericide:
Tetramethylthiuram Disulfide has been used as a bactericide applied directly to the skin or incorporated into soap.
Toxicity
Acute oral-rat: LD50 780~865mg/kg; Acute oral-mice: LD50 1500~2000mg/kg. Accelerator T has an irritation effect on the human mucous membrane and skin. People long-term exposure to it have allergic reactions while drinking alcohol. Carp LC50 4mg/L.
Production method
The preparation of sodium dimethyl dithiocarbamate(SDD): the reaction of dimethylamine hydrochloride and carbon disulfide in the presence of sodium hydroxide can generate sodium dimethylamino dithiocarbamate . The reaction temperature is 50~55℃ and the pH value is 8~9.
The preparation of thiram: the reaction of SDD (or Diram) and hydrogen peroxide in the presence of sulfuric acid can produce thiram. The reaction temperature is controlled at 10 ℃ below and the end pH value is 3 to 4. Chlorine can also be used instead of hydrogen peroxide and sulfuric acid. The reaction is performed in the sieve tray tower, from the bottom of which the diluted chlorine is introduced and from the top of which 5% sodium solution is sprayed, which is called chlorine-air oxidation method. There are also other methods, such as sodium nitrite oxidation or electrolytic oxidation.
Hazards & Safety Information
Category :Toxic substances
Toxicity classification :? moderate toxicity
Acute Toxicity : Oral-Rat LD50: 560 mg/kg; Oral-mouse LD50: 1250 mg/kg
Stimulation Data: Eye-Rabbit 100 mg/24hours Moderate
Flammability Hazardous characteristics:
The products can decompose into toxic nitrogen oxides and sulfur oxides when meeting heat.
Storage and transportation characteristics :
Storehouse should be low-temperature, well-ventilated and dry; the storage and transportation should be separated form food raw materials.
Extinguishing agent : sand, dry powder, foam
Occupational Standard :TWA 5 mg/m3; STEL 10 mg/m3
Air & Water Reactions
Insoluble in water. Decomposes in acidic media to give toxic products. Decomposes to an extent on prolonged exposure to heat, air or moisture.
Reactivity Profile
TMTD is incompatible with oxidizing materials and strong acids. Also incompatible with strong alkalis and nitrating agents .
Hazard
Toxic by ingestion and inhalation, irritant
to skin and eyes. Body weight and hematologic
effects. Questionable carcinogen.
Health Hazard
Inhalation of dust may cause respiratory irritation. Liquid irritates eyes and skin and may cause allergic eczema in sensitive individuals. Ingestion causes nausea, vomiting, and diarrhea, all of which may be persistent; paralysis may develop.
Fire Hazard
Special Hazards of Combustion Products: Toxic and irritating oxides of sulfur are formed. Carbon disulfide may be formed from unburned material.
Trade name
AAPIROL?; AATACK?; AATIRAM?;
ACCELERATOR T?; ACCELERATOR THIURAM?;
ACCEL TMT?; AGROSOL POUR-ON?; ANLES?;
ARASAN?[C]; ATIRAM?; ATTACK?; AULES?;
CHIPCO THIRAM 75?; CRYLCOAT?; CUNITEX?;
CYURAM DS?; DELSAN?; EBECRYL?; EKAGOM
TB?; EVERSHIELD T SEED PROTECTORANT?;
FALITIRAM?; FERMIDE?; FERNACOL?;
FERNASAN?; FERNIDE?; FLO PRO T SEED
PROTECTANT?; FMC 2070?[C]; FORMALSOL?;
HERMAL?; HERYL?; HEXATHIR?; HY-VIC?;
KODIAK T?; KREGASAN?; LIQUID MOLY-CO-THI?;
MERCURAM?; METIURAC?; MOLY-T?; NA2771?;
NOBECUTAN?; NOMERSAN?; NORMERSAN?;
OPTIMA?; PANORAM 75?; POLYRAM
ULTRA?; POMARSOL?; POMARSOL FORTE?;
POMASOL?; PRO-GRO?; PURALIN?; RAXIL?;
REZIFILM?; ROOTONE?; ROYAL TMTD?; RTUBAYTAN-
THIRAM?; RTU FLOWABLE SOYBEAN
FUNGICIDE?; SADOPLON?; SOLUCRYL?;
SPOTRETE?; SPOTRETE-F?; SQ 1489?; SRANANSF-
X?; TERSAN 75?[C]; TERSANTETRAMETHYL
DIURANE SULFIDE?; TETRAPOM?;
TETRASIPTON?; THIANOSAN?; THILLATE?;
THIMAR?; THIMER?; THIOKNOCK?; THIOSAN?;
THIOSCABIN?; THIOTEX?; THIOTOX?; THIRAM
75?; THIRAM 80?; THIRAMAD?; THIRAM B?;
THIRAMPA?; THIRASAN?; THIULIN?; THIULIX?;
THIURAD?; THIURAMIN?; THIURAMYL?;
THYLATE?; TIRAMPA?; TITAN FL?; TRAMETAN?;
TRIDIPAM?; TRIPOMOL?; TUADS?; TUEX?;
TULISAN?; UCECOAT?; UCECRYL?; UVECRYL?;
VANCIDA TM-95?; VANCIDE TM?; VITAFLO 280?;
VITAVAX? Thiram; VITAVAX-T?; VUAGT-1-4?;
VULCAFOR TMTD?; VULKACIT MTIC?;
VULKACIT THIURAM?; VULKACIT THIURAM/C?
Contact allergens
TITD is a rubber vulcanization accelerator
Contact allergens
This rubber chemical, accelerator of vulcanization, represents the most commonly positive allergen contained in “thiuram mix.” The most frequent occupational categories are the metal industry, homemakers, health services and laboratories, the building industry, and shoemakers. It is also widely used as a fungicide, belonging to the dithiocarbamate group of carrots, bulbs, and woods, and as an insecticide. Thiram is the agricultural name for thiuram.
Safety Profile
Poison by ingestion and
intraperitoneal routes. Questionable
carcinogen with experimental tumorigenic
and teratogenic data. Other experimental
reproductive effects. Mutation data
reported, Affects human pulmonary system.
A rmld allergen and irritant. Acute poisoning
in experimental animals produced liver,
hdney, and brain damage. Dangerous in a
fire; see NITROGEN MONOXIDE and
SULFUR DIOXIDE.
Potential Exposure
Thiram is a dithiocarbamate. Some thiurams have been used as rubber components: thiram is used as a rubber accelerator and vulcanizer; a seed, nut, fruit, and mushroom disinfectant; a bacteriostat for edible oils and fats; and as an ingredient in suntan and antiseptic sprays and soaps. It is also used as a fungicide, rodent repellent; wood preservative; and may be used in the blending of lubricant oils.
Carcinogenicity
Thiram also was not carcinogenic in rats
by gavage or in mice by single subcutaneous
injection. In skin painting studies in mice
thiram had tumor-initiating and -promoting
activity but was not a complete carcinogen.
Thiram was genotoxic to insects, plants,
fungi, and bacteria: it induced sister chromatid
exchange and unscheduled DNA synthesis in
cultured human cells. Despite established
genotoxicity in vitro, it showed no clastogenic
and/or aneugenic activity in vivo after oral
administration to mice at the maximum tolerated
dose.
Environmental Fate
Biological. In both soils and water, chemical and biological mediated reactions can
transform thiram to compounds containing the mercaptan group (Alexander, 1981).
Odeyemi and Alexander (1977) isolated three strains of Rhizobium sp. that degraded
thiram. One of these strains, Rhizobium meliloti, metabolized thiram to yield dimethy-
lamine (DMA) and carbon disul?de which formed spontaneously from dimethyldithiocar-
bamate (DMDT). The conversion of DMDT to DMA and carbon disul?de occurred via
enzymatic and nonenzymatic mechanisms (Odeyemi and Alexander, 1977).When thiram (100 ppm) was inoculated with activated sludge (30 ppm) at 25°C and
pH 7.0 for two weeks, 30% degraded. Metabolites included methionine, elemental sulfur,
formaldehyde, dimethyldithiocarbamate-α-aminobutyric acid and the corresponding keto
aciTo a non-autoclaved alluvial sandy loam (pH 7.3) fortified and inoculated with the
bacterium Pseudomonas aeruginosa, 40 and 86% degradation were observed after 4 and
24 days, respectively. In autoclaved soil, thiram degradation was not affected. DegradatSoil. Decomposes in soils to carbon disul?de and dimethylamine (Sisler and Cox,
1954; Kaars Sijpesteijn et al., 1977). When a spodosol (pH 3.8) pretreated with thiram
was incubated for 24 days at 30°C and relative humidity of 60–90%, dimethylamine formed
as the major product. Minor degradative products included nitrite ions (nitration reduction)
and dimethylnitrosamine (Ayanaba et al., 1973).Plant. Major plant metabolites are ethylene thiourea, thiram monosul?de, ethylene
thiram disul?de and sulfur (Hartley and Kidd, 1987).
Metabolic pathway
Dialkyldithiocarbamates chelate copper and inhibit pyruvate dehydrogenase.
It is likely that the mode of action of chelators is principally through
their effect on lipoamide containing dehydrogenases (Corbett et al., 1984).
Thiram generates dimethyldithiocarbamic acid by being cleaved in acidic
conditions and in biological media. The acid is conjugated with glucose
and alanine in plants and with glucuronic acid in mammals. Dimethyldithiocarbamic
acid is further degraded to dimethylamine and CS2. An
extensive review of the properties of dithiocarbamate pesticides was published
by the World Health Organisation (WHO, 1988) from which much
of the following information is taken.
Shipping
UN2771 Thiocarbamate pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.
Purification Methods
Crystallise thiram (three times) from boiling CHCl3, then recrystallise it from boiling CHCl3 by adding EtOH dropwise to initiate crystallisation, and allow it to cool. Finally it is precipitated from cold CHCl3 by adding EtOH (which retains the monosulfide in solution). [Ferington & Tobolsky J Am Chem Soc 77 4510 1955, Beilstein 4 IV 242.]
Degradation
Thiram is decomposed in acidic media. It deteriorates on prolonged
exposure to heat, air or moisture. DT50 values are estimated as 128 days,
18 days and 9 hours at pH 4, 7 and 9, respectively (PM). The dimethyldithiocarbamate
(2) is stable in alkaline media but unstable in acidic
conditions, decomposing to dimethylamine and carbon disulfide. In
water, the dimethyldithiocarbamate can be oxidatively degraded to a
number of products. The rate of degradation depends on pH and the
type of any cations that might be present. The rate of decomposition and
production of CS2 is decreased by cations in the following order Na+ >
Zn2+> Fe3+> Cu2+. Thiram was completely degraded in sewage water in
12 days.
An ethanolic solution of unlabelled thiram (4 g l-1) was exposed to UV
light for 48 hours. The reaction tube was encircled by low pressure Hg
lamps that gave more than 85% of their total radiation at 253.7 nm. Pure
nitrogen was bubbled through the solutions. Photo-oxidation studies were
done similarly except that oxygen was bubbled through the solution.
In further experiments, irradiation was by visible light from a tungsten
lamp and again oxygen was bubbled through the solution. The outlet
gases from the UV study were condensed in a cold trap and analysed
by GC-MS. Traces of carbon disulfide and dimethylamine were
identified. The reaction mixture was also analysed by GC-MS and
three products were identified as tetramethyl hydrazine (3), N,N-dimethylthioformamide
(4) and tetramethylthiourea (5). The identity of
the latter was confirmed by IR and NMR. The reaction mixture was concentrated
and applied to TLC plates and sulfur and tetramethylthiourea
(5) were identified as the main products of photolysis. The same
products with the addition of sulfur dioxide and carbon dioxide were
produced by UV light and oxygen. Oxidation of thiram in the presence
of visible light together with Rose Bengal as a photosensitiser also gave the same products in almost identical yields. The results confirm that
C-S and S-S bond fissions are primary photochemical steps with
dithiocarbamates.
Toxicity evaluation
Thiram cytotoxicity appears to result from its potential to
disrupt cellular defense mechanisms against oxidative stress. In
cultured human skin fibroblast, thiram results in an increase in
oxidative markers such as lipid peroxidation and oxidation of
reduced glutathione and decrease in other endogenous antioxidant.
Toxic effects of thiram have been described in humans
and animal model systems ranging from liver injury, testicular
toxicity, ophthalmological changes, and development of
micronuclei in bone marrow. However, the mechanisms of
these effects are not characterized and inconsistent across
various studies.
Incompatibilities
Dust may form explosive mixture with air. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine,fluorine, etc.); contact may cause fires or explosions. Keep away from strong alkaline materials, strong acids, strong bases and nitrating agents.
Waste Disposal
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal. Thiram can be dissolved in alcohol or other flammable solvent and burned in an incinerator with an afterburner and scrubber.
Check Digit Verification of cas no
The CAS Registry Mumber 137-26-8 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 1,3 and 7 respectively; the second part has 2 digits, 2 and 6 respectively.
Calculate Digit Verification of CAS Registry Number 137-26:
(5*1)+(4*3)+(3*7)+(2*2)+(1*6)=48
48 % 10 = 8
So 137-26-8 is a valid CAS Registry Number.
InChI:InChI=1/C6H12N2S4/c1-7(2)5(9)11-12-6(10)8(3)4/h1-4H3
137-26-8Relevant articles and documents
Trimethylchlorosilane (TMSCl) and cyanuric chloride (CC) catalyzed efficient oxidative coupling of thiols with dimethylsulfoxide
Karimi, Babak,Hazarkhani, Hassan,Zareyee, Daryoush
, p. 2513 - 2516 (2002)
Different types of thiols were rapidly and efficiently converted to disulfides using DMSO in the presence of catalytic amounts of either trimethylchlorosilane (TMSCl) or cyanuric chloride (CC).
Development of an improved method for conversion of thiuram disulfides into N,N-dialkylcarbamoyl halides and derivatives
Adeppa,Rupainwar,Misra, Krishna
, p. 285 - 290 (2011)
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.
Carbonic anhydrase inhibitors: Sulfonamides as antitumor agents?
Supuran, Claudiu T,Briganti, Fabrizio,Tilli, Silvia,Chegwidden,Scozzafava, Andrea
, p. 703 - 714 (2001)
Novel sulfonamide inhibitors of the zinc enzyme carbonic anhydrase CA, EC 4.2.1.1) were prepared by reaction of aromatic or heterocyclic sulfonamides containing amino, imino, or hydrazino moieties with N,N-dialkyldithiocarbamates in the presence of oxidiz
Zinc(II)-catalyzed disproportionation in rubber: The mechanism of sulfur vulcanization revisited
Nieuwenhuizen, Peter J.,Timal, Sandjai,Haasnoot, Jaap G.,Spek, Anthony L.,Reedijk, Jan
, p. 1846 - 1851 (1997)
Model studies have shown that cross-link precursors, that is, intermediates in the sulfur vulcanization of rubber, are transformed into cross-links by a nonsymmetric but regioselective disproportionation mechanism. Thus, two equivalents of the cross-link precursor of the type R-S-S-X are transformed into X-S-X and the actual cross-link R-S-S-S-R. Exchange of sulfur atoms is a prerequisite. A mechanism involving an S(N)i' reaction with an allylic moiety, suggested in the literature, has not been observed. The disproportionation reaction is catalyzed by rubber-soluble zinc-dithio-carbamate complexes, an important class of vulcanization accelerators. By virtue of ligand-functional-group exchange reactions these complexes serve to transport and exchange sulfur atoms.
Microfluidic electrosynthesis of thiuram disulfides
Zheng, Siyuan,Wang, Kai,Luo, Guangsheng
, p. 582 - 591 (2021)
An electrolytic approach to sodium dithiocarbamates based on a microfluidic reactor is proposed for the green synthesis of thiuram disulfides, which are versatile free radical initiators. The electro-oxidation reactions avoid the over-oxidation of sodium dithiocarbamates and the generation of waste salts, which have perplexed the industry for a long time. This microfluidic electrolysis method prevents solid deposition by introducing liquid-liquid Taylor flow into the microchannel, and promotes the synthesis efficiency of thiuram disulfides with the enlargement of the electrode-specific surface area. The highest yield of thiuram disulfide was 88% in the experiment without any oxidation by-products. The Faraday efficiencies of most reactions are higher than 96%, showing the excellent electronic utilization. In addition to improving the environmental friendliness of sodium dithiocarbamate oxidation, the electrosynthesis method helps to create a cyclic technology of thiuram disulfide synthesis via the combination of sodium dithiocarbamate generation in a packed bed reactor. The cyclic technology finally achieved >99% atom utilization in thiuram disulfide synthesis from secondary amines and carbon disulfide. This journal is
Method for preparing tetraalkyl thiuram disulfide through photocatalytic oxidation
-
Paragraph 0061-0064, (2021/02/13)
The invention relates to a method for preparing tetraalkyl thiuram disulfide by photocatalytic oxidation. The method comprises the following steps: carrying out mixed reaction on secondary amine, carbon disulfide and a catalyst in a medium to generate an intermediate product; and carrying out catalytic oxidation reaction on the intermediate product under illumination to obtain tetraalkyl thiuram disulfide. According to the invention, the method is high in reaction speed and mild in condition, and energy conservation and efficiency improvement are achieved; the used medium and catalyst can be recycled, so that the resource utilization rate is improved; and the method does not produce inorganic salt by-products, and the product has high yield and high purity.
Continuous-flow step-economical synthesis of thiuram disulfidesviavisible-light photocatalytic aerobic oxidation
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
supporting information, p. 1280 - 1285 (2021/02/26)
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.
Development of disulfide-derived fructose-1,6-bisphosphatase (FBPase) covalent inhibitors for the treatment of type 2 diabetes
Xu, Yi-xiang,Huang, Yun-yuan,Song, Rong-rong,Ren, Yan-liang,Chen, Xin,Zhang, Chao,Mao, Fei,Li, Xiao-kang,Zhu, Jin,Ni, Shuai-shuai,Wan, Jian,Li, Jian
, (2020/07/25)
Fructose-1,6-bisphosphatase (FBPase), as a key rate-limiting enzyme in the gluconeogenesis (GNG) pathway, represents a practical therapeutic strategy for type 2 diabetes (T2D). Our previous work first identified cysteine residue 128 (C128) was an important allosteric site in the structure of FBPase, while pharmacologically targeting C128 attenuated the catalytic ability of FBPase. Herein, ten approved cysteine covalent drugs were selected for exploring FBPase inhibitory activities, and the alcohol deterrent disulfiram displayed superior inhibitory efficacy among those drugs. Based on the structure of lead compound disulfiram, 58 disulfide-derived compounds were designed and synthesized for investigating FBPase inhibitory activities. Optimal compound 3a exhibited significant FBPase inhibition and glucose-lowering efficacy in vitro and in vivo. Furthermore, 3a covalently modified the C128 site, and then regulated the N125–S124–S123 allosteric pathway of FBPase in mechanism. In summary, 3a has the potential to be a novel FBPase inhibitor for T2D therapy.
Photocatalytic H2-Evolution by Homogeneous Molybdenum Sulfide Clusters Supported by Dithiocarbamate Ligands
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.
, p. 16458 - 16474 (2019/12/24)
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.
Synthetic method of tetramethylthiuram disulfide drug intermediate
-
Paragraph 0014; 0019; 0020; 0023; 0024; 0025-0028, (2018/07/30)
The invention discloses a synthetic method of a tetramethylthiuram disulfide drug intermediate. The synthetic method comprises the following steps: adding a dimethylamine solution and a sodium nitratesolution into a reaction container, controlling the solution temperature to be 20 to 24 DEG C, controlling the stirring speed to be 230 to 260 rpm, adding a 1-pentanethiol solution, adding a thiophane solution in batches within 30 to 50 min, and continuously reacting for 80 to 120 min; then adding nickel bromide powder, controlling the solution temperature to be 15 to 18 DEG C, adding lead tetraacetate, continuously reacting for 2 to 4 h, standing for 30 to 50 min, adding a potassium chloride solution, layering the solution to separate an oil layer, washing with a 2-heptanone solution for 20to 40 min, carrying out recrystallization in a 1-chloropropane solution, and carrying out dehydration of a dehydrating agent so as to obtain the finished product tetramethylthiuram disulfide.