Dithiocarbamic salts

Chemical antiozonants comprise the second general class of commercial antiozonants. Of the many compounds reported to be chemical antiozonants, nearly all contain nitrogen. Compound classes include derivatives of l,2-dihydro-2,2,4-trimethylquinoline, A/-substituted ureas or thioureas, substituted pyrroles, and nickel or zinc dithiocarbamate salts (see also Antioxidants). The most effective antiozonants, however, are derivatives of -phenylenediamine... 

EDA reacts readily with two moles of CS2 in aqueous sodium hydroxide to form the bis sodium dithiocarbamate. When aqueous ammonia and 2inc oxide (or manganese oxide or its hydrate) is used with a basic catalyst, the 2inc (or manganese) dithiocarbamate salt is isolated. Alternatively, the disodium salt can react with ZnSO or MnSO followed by dehydration in an organic solvent to yield the same salts (48—50). 

When carbon disulfide reacts with either aliphatic or aromatic, primary or secondary amines, dithiocarbamate salts are formed (8, 9). The following is an example. 

By using an alkali-metal hydroxide in situ as a proton acceptor, the alkali-metal dithiocarbamate salts, having various degrees of hydration, may be obtained (17). 

Mesoionic 1,2,3,4-oxatriazolium-5-thiolates (172) are convenient starting materials for mesoionic thiatriazole 5-oxides. Thus arylhydrazines and carbon disulfide in ethanol yield arylhydrazinium dithiocarbamate salts, which are nitrosated with sodium nitrite in aqueous hydrochloric acid to give yellow l,2,3,4-oxatriazolium-5-thiolates (172). These heterocycles are isomerized by warming with ammonium hydroxide in ethanol to give colorless crystalline l,2,3,4-thiatriazolium-5-olates (173) (Scheme 36) <76CC306>. 

Sodium dithiocarbamates are similarly converted to aryl dithiocarbamates with polymeric aryliodonium bisulfates 20 derived from styrene (Scheme 41) [116]. The high regioselectivity of C-I bond cleavage in 20 is noteworthy, only trace amounts of iodoarenes [Arl] having been detected in occasional cases . Regioselective conversions of p-phenylenebis(phenyliodonium) ditriflate (21) top-phenylenebis(dithiocarbamates) with dithiocarbamate salts have also been reported (Scheme 41) [117]. 

Optically active dithiocarbamates Co(S2CR2)3 (R = Me, Et, Pr, Bun, Bu1, Bz, Cy, or pip) can be prepared from the potassium dithiocarbamate salts and the optically active K[Co(edta)] or K[Co(pdta)] (pdta = 1,2-propanediaminetetra-acetate).368 The optical inversion of ( + )546-[Co(pyr-dtc)3] (pyr-dtc = NN-dipyrrolidyldithio-carbamate) in chloroform has been studied by loss of optical activity by polarimetry.3 68... 

The analysis of non-polar solutes by high performance liquid chromatography is generally a simple task, especially if reversed-phase systems are used. However, many compounds of environmental interest, such as dithiocarbamate salts and inorganic anions are ionized species. By their very nature it is difficult to chromatograph these well hydrated hydrophilic species. 

The activity of this dithiocarbamate salt is due to its decomposition to methylisothiocyanate (44 ). 

Cure system species, accelerators and their reaction products This class of additive can present problems as they are often thermally labile, reactive and, in some cases, have a degree of ionic character (e.g. zinc dithiocarbamate salts). In these cases LC-MS is a more appropriate technique than GC-MS. It is also easier to use LC-MS with a number of the approved food simulants as they can be injected directly into the instrument, being compatible with the mobile phase. In some cases the reaction products (e.g. aniline from diphenyl guanidine, and benzothiazole from thiazole and sulphonamide accelerators) are stable and so GC and GC-MS can be used. Peroxides are popular curatives for food use rubbers and the stable, breakdown products of these can be easily detected by GC-MS. 

A study in Japan looked at the migration of dimethylamine (DMA) into water and hydrochloric acid from 25 rubber articles (including stoppers, chopping boards, spatulas and teats). After one hour of refluxing, the water extracts contained 3 to 1280 mg of DMA per kg of rubber. The study also showed that the thiuram accelerators that were present (TMTD and TMTM) were almost totally decomposed to DMA (a nitrosatable substance). However, in the case of dimethyl dithiocarbamate salts (sodium, zinc, copper and lead examples were included), the decomposition to DMA depended on the solvent used and the salt compound. 

The formation of desaurins from ketones, carbon disulfide, and base 1275,1281,1282,1285-1290 believed to involve nucleophilic attack on a thioketene by the dianion of a 1,1-dimercaptoalkene, as shown for the synthesis of 572. Related syntheses involve the use of thiophosgene instead of carbon disulfide and the use of diazoalkanes or phosphonium and sulfonium ylides instead of a ketone and base. Treatment of perfluoroiso-butylene with fluoride ion and elemental sulfur in a dipolar, aprotic solvent ° °° or with sources of anionic sulfur (potassium sulfide, sodium hydrosulfide,potassium thiocyanate,sodium thiosulfate, dithiocarbamate salts, dithiophosphate salts ) give the dimer (573) of bis(trifIuoromethyl)-thioketene. Similarly, other 2,4-bis(methylene)-l,4-dithietanes are obtained by treating 2,2-dichlorovinyl ketones with anionic sulfur re-... 

Previously, the molecular structures of many thiuram di- [20-31] (see Fig. 1), mono- [32], trisulfides [33] and thiuram disulfide derivatives, in which R2NC(S)S- groups are linked by polymethylene chains [34], have been determined by single-crystal X-ray diffraction studies. A number of polycrystalline tetralkylthiuram disulfides and their cyclic analogs have also been recently studied by means of solid-state and CP/MAS NMR [31]. Assignments and and chemical shift data for eight (1-8) selected thiuram disulfide compounds and initial dithiocarbamate salts are shown in Table 1. The observed differences in and isotropic chemical shifts for these molecular systems can be attributed to simultaneous manifestation of the inductive effect of alkyl substituents and to the mesomeric effect of the dithiocarbamate groups discussed below. 

Aquatreat [ALCOA]. TM for water-soluble dithiocarbamate salt bactericides. 

A valuable alternative for the preparation of A -sugar dithiocarbamates is the reaction of a sodium dithiocarbamate salt, obtained from the condensation of an amino sugar with carbon disulfide in the presence of base, with an excess of alcohol97 or alkyl iodide190 (Scheme 50). 

Closely related are the 1-benzylamino-l-deoxylactitol dithiocarbamate salts developed by Eybl and co-workers316 317 for the same purpose. However, the most important application of 175 is, probably, its use as a nontoxic, water-soluble nitric oxide probe in vivo. In view of the central importance that this gaseous free-radical species plays in regulating a broad range of important biological functions, its detection and quantification near its site of production and action is of prime importance. For this purpose, the ferrous salt of MGD, which forms a stable water-soluble mononitrosyl iron-dithiocarbamate complex (176) with a characteristic electron spin resonance (ESR) spectrum at room temperature, is currently used.318-323... 

Dithiocarbamic esters can generally be obtained easily by alkylation or arylation of the corresponding dithiocarbamic salts 792-798 other methods are addition of thiols to isothiocyanic esters,792 treatment of chlorodithio-formic esters with amines,792 and reaction of thiocarbamoyl chlorides with thiolates.786... 

Dithiocarbamic salts are suitable starting materials for the preparation of isothiocyanic esters (mustard oils), their reactions with heavy-metal salts,771 chloroformic esters,772 phosgene,768 carbodiimides,805 phosphorus oxychloride,806 aryl cyanates,732 or sodium hypochlorite807 usually giving good yields. Reaction of amines 808,809 or their hydrochlorides with thiophosgene810 is also generally applicable. 

Preparation of isothiocyanic esters from dithiocarbamic salts ... 

Thiadiazines 238a and 238b are prepared from primary amines and carbon disulfide under basic conditions. The potassium dithiocarbamate salts 239 formed react with 2equiv of formaldehyde and the corresponding primary amine/amino acid to furnish the desired thiadiazines 238 (Scheme 45) <1999JME5359>. 

Attachment of isoniazid (INH) to a tetrahydro-277-[l,3,5]thiadiazine-2-thione moiety has been carried out via the dithiocarbamate salt 239 using a similar approach (see Scheme 46) <2004MI35>. 

Many of the methods used for the preparation of 1,3,5-oxadiazines also apply to the 1,3,5-thiadiazines. Similar to the oxygen analogs, the starting Wnitroguanidine can be treated with formaldehyde, but in the presence of sodium sulfide to afford the Mannich-type cyclization product 4-nitroimino-l,3,5-thiadiazines (Section 9.09.9.1.2). Primary amines react with carbon disulfide under basic conditions to form dithiocarbamate salts which react with 2 equiv of formaldehyde and a second primary amine to furnish tetrahydro-2//-l,3,5-thiadiazine-2-thiones (Section 9.09.9.1.3). 

Alkali metal tertiary amines dithiocarbamate salt catalysts for the preparation of polyisocyanurates [44]. 

Similarly, carbonimidoyl dichlorides X are obtained upon chlorination of dithiocarbamate salts XIII (5.32,93,98 benzoyldithiocarbamates ( ). 

Many compounds have been reported in the literature to be chemical antiozonants, and nearly all contain nitrogen. Compound classes include derivatives of 2,2,4-trimethyl-l, 2-dihydroquinoline, N-substituted ureas or thioureas, substituted pyrroles, and nickel or zinc dithiocarbamate salts. The most effective antiozonants, however, are derivatives of p-phenylenediamine (p-PDA). The commercial materials are grouped into three classes N,N -dialkyl-p-PDAs, Nalkyl-N -ary 1-p-PDAs, and NX-diary 1-p-PI) As. The NX-dialkyl-p-PDAs (where the alkyl group may be 1-methylheptyl, l-ethyl-3-methylpentyl, 1,4-dimethylpentyl, or cyclohexyl) are the most effective in terms of their reactivity to ozone. These derivatives increase the critical stress required for the initiation of crack growth, and they also reduce the rate of crack growth significantly. The sec-alkyl group is most active, for reasons that are not yet completely clear. The drawbacks of these derivatives are ... 

Dithiocarbamate salts Biological activity, preparation, and utility in organic synthesis, particularly, in synthesis of heterocycles 12JSC605. 

The nucleophilic reactivity of dithiocarbamate anions has been the subject of a variety of papers, describing the reactions of alkali-metal dithiocarbamate salts with the common organic solvents methylene chloride, chloroform, and acetonitrile, with alkyl halides, a-halogeno-ketones and -aldehydes, chloroacetates, chloro-substituted j-triazines, phthaloyl chloride, oxalyl chloride, and with AW-dimethyl-5 S -dimethyldithiocarbamidium perchlorate. The nucleophilic addition reaction of dialkylammonium NN-dialkyldithiocarbamates with olefins, yielding alkyl dithiocarbamates, has also been described. ... 

In solution or at the end of emulsion polymerization, tetraalkyl thiuram disulfides are added to the emulsion. Very little reaction occurs at this point. Alkali metal salts of dithiocarbamates, secondary amines, or alkali salts of mercaptoben-zothiazole (28) are added to initiate the peptization reaction through sulfur-sulfur bond cleavage. The polychloroprene sulfide ion reacts with the tetraalkyl thiuram disulfide to cap the end of the polymer and generate a second dithiocarbamate salt. The second dithiocarbamate salt propagates the peptization reaction. Thus, the final polymer molecular weight and bulk Mooney viscosity will depend on initial sulfur concentration in the copolymerization and the concentration of tetraalkyl thiuram disulfide and dithiocarbamate salt added during the peptization step. 

The emulsion was cooled to 20° C. A dithiocarbamate salt or secondary amine was added and the emulsion aged for 8 h to peptize the polymer. The bulk Mooney viscosity of the polymer was thus reduced to levels suitable for rubber processing. 

In 2009, Patel and co-workers developed two ligand-assisted Cu(i)-cata-lyzed sequential intra- and intermolecular S-arylations for the synthesis of arylthiobenzothiazoles in a one-pot manner without an inert atmosphere (Scheme 2.140). Low catalyst loading, inexpensive metal catalyst and ligand, lower reaction temperature, and shorter reaction times make this method superior to all reported methods for the synthesis of aiylthio-benzothiazole. In detail, the reaction started with an intramolecular S-aiy-lation of a dithiocarbamate salt and yielded benzothiazol-2-thiol or MBT (2-mercaptobenzothiazole), which was then followed by an intermolecular C-S coupling giving 2-atylthiobenzothiazoles directly. In the communication, the authors found the following order of reactivity in aryl iodides P-NO2 > 0-NO2 > o-COOMe > m-Cl > H > p-Me > p-OMe. 

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