Amines reactions, carbon disulfide

Recently, it has been reported that l,3-dithiole-2-thione (12) reacts with primary amine to give the corresponding thiourea and A-4-thia2oline-2-thione (Scheme 5) (14). 5-Methylenethiazolidine-2-thione (13) obtained from the reaction of propargyl amine and carbon disulfide... 

Disulfiram may be made by the reaction of diethyl amine with carbon disulfide in the presence of sodium hydroxide. The (CjHjljNCSSNa intermediate is oxidatively coupled using hydrogen peroxide to give disulfiram. 

Salts of dithiocarbamic acid can be prepared by the addition of primary or secondary amines to carbon disulfide. This reaction is similar to 16-9. Hydrogen sulfide can be eliminated from the product, directly or indirectly, to give isothiocyanates (RNCS). Isothiocyanates can be obtained directly by the reaction of primary amines and CS2 in pyridine in the presence of DCC. ° In the presence of diphenyl phosphite and pyridine, primary amines add to CO2 and to CS2 to give, respectively, symmetrically substituted ureas and thioureas ... 

N-Bis(methylthio)methylene derivatives of amines (iminodithiocarbonates) were first introduced by Hoppe and Beckmann468 for the synthesis of a-amino acids from glycine. The A bis(methylthio)methyleneamines are prepared by reaction of a primary amine with carbon disulfide (HAZARD) in the presence of triethylamine and iodomethane to form a methyl dithiocarbamate derivative, which is then S-alkylated with a second equivalent of iodomethane in the presence of potassium carbonate as the base. Scheme 8,233 illustrates an alternative one pot procedure applied to the synthesis of /erf-butyl N-[bis(methylthio)-methylene]glycinate and its use in diastereoselective conjugate addition under... 

Thiourea (98) was first prepared in 1870 by heating ammonium thiocyanate (99) (Scheme 54). The reaction is analogous to the historic preparation of urea (Wohler, 1828) which involved heating ammonium cyanate. Thioureas generally are stable crystalline solids which are useful in the synthesis of heterocyclic compounds. Symmetrical thioureas (100) may be obtained by the action of amines on carbon disulfide, and the procedure can be extended to the synthesis of cyclic thioureas (101) (Scheme 55). The reaction occurs via the intermediate (102) which on subsequent treatment with either ammonia or an amine yields the corresponding... 

Other preparative routes to isothiocyanates involve reaction of amines with carbon disulfide and alkali and subsequent treatment of the dithiocarbamate (112) with phosgene or ethyl chloroformate. Alternatively, the dithiocarbamate may be reacted with mercury(II) chloride or lead tetranitrate (Scheme 61). Amines can also be reacted with thiophosgene or N,N-diethyl thiocarbamoyl chloride (113) (Scheme 61). 

These are easily prepared by the reaction of amines with carbon disulfide (1) in the presence of alkali (Scheme 17).2 The synthesis of dithiocarba mates (4) was first reported by Debus in 1850. Dithiocarba mates (4) form metal chelates, and sodium dimethyl dithiocarbamate is used in quantitative inorganic analysis for the estimation of metals, e.g. copper and zinc. Dithiocarba mates are also employed as vulcanisation accelerators and antioxidants in the rubber industry, and as agricultural fungicides.3 The parent dithiocarbamic acids are unstable, decomposing to thiocyanic acid and hydrogen sulfide however, the salts and esters are stable compounds. Dithiocarba mates (4) are oxidised by mild oxidants to the thiuram disulfides (38) (Scheme 17). 

When alkyl thiocyanates (39) are heated they isomerize to the corresponding isothiocyanates (43) (Scheme 24).5 Isothiocyanates (43) are better obtained by heating a primary amine with carbon disulfide (1) and mercury(II) chloride (Hofmann mustard oil reaction, 1868) (Scheme 25). 

Dithiocarbamic acids, R2NC(S)SH, are rather unstable and seldom isolated or used as such. Usually their alkali metal or (substituted) ammonium salts are prepared for further use as starting materials in the synthesis of various metal complexes or organometallic derivatives. The most common is the reaction of primary or secondary amines with carbon disulfide in alkaline medium. 

VI. Reaction of dithiocarbamic acids (amines and carbon disulfide). . . 610... 

Under this heading are brought together the heterocyclic thioxo compounds which may be synthesized from an amine and carbon disulfide (dithiocarbamic acids) with a difunctional compound. Generally the dithiocarbamic acid (CLXXXVI) is prepared first and subsequently cyclized. However, this is not always necessary in several instances the desired heterocychc thioxo compound may be obtained from a mixture of the three reagents. These cyclization reactions are shown schematically in scheme t. 

The salts of metham are not stable in solid form, so they are marketed as relatively dilute aqueous solutions, which makes their use rather expensive. When the reaction of methyl amine with carbon disulfide is carried out in the presence of formaldehyde, the stable solid compound 3,5-dimethyl-tetrahydro-1,3,5-thiadiazine-2-thione, or dazomet (11), is obtained. It is applied as a dust or as a concentrated prill. 

All of the dithiocarbamates are decomposed in acid media into corresponding amine and carbon disulfide. Their analytical determination is based on this reaction (Clarke et al.. 1951). 

Incompatible with strong oxidizers acids, water (slowly decomposes, forming amine and carbon disulfide). Reaction with nitrosating compounds (i.e., nitrogen oxides, nitrosyl chloride, nitrite esters, metal nitrates and nitroso compounds, etc.) can cause the formation of carcinogenic N-nitrosodiethylamine. 

The Schiff base or enamine reaction has been employed to modify aldehydes and ketones by condensation with a primary amine (reaction 1) and to condense primary amines with a carbonyl compound (reaction 2). A similar reaction between primary amines and carbon disulfide yields isothiocyanates or mustard oils (reaction 3). These three possibilities for derivative formation will be discussed in this chapter. 

CS2 as a type of liquid sulfur source was applied in benzothiazole synthesis as well. In 2011, Ma and co-workers found that copper salt can catalyse the reaction between 2-haloanilines and dithiocarbamate, which was generated in situ from amines and carbon disulfide (Scheme 2.145a). ° 2-N-Substi-tuted benzothiazoles were produced in good yields. Later on, they found that thiols can be applied as well. Condensation of carbon disulfide with thiols in... 

The authors proposed a similar mechanism for the 6-MCR (Scheme 7.26). In both cases, the Ugi intermediate 59 contained an active triple bond, which was suitable for further nucleophilic addition reactions of the nucleophiles present in the medium. However, in this case, the nucleophile was formed by reaction of the amine to carbon disulfide. 

All these reactions start by the addition of the starting amine to carbon disulfide to yield intermediate 44, which then adds in various fashions to the organic electrophiles. 

Isothiocyanates are readily made by reaction of a primary aromatic amine with carbon disulfide/triethylamine followed by ethyl chloroformate/triethylamine and by treatment of the amine either with thiophos-gene, calcium carbonate, chloroform, water [138, 139] or with carbon disulfide, N,N -dicyclohexylcarbodiimide, pyridine [140, 141],... 

Figure 6. Mechanism of the reaction of secondary amines with carbon disulfide.

Ma et al. developed a copper-catalyzed cascade condensation/S-arylation/hetero-cyclization for the three-component synthesis of 2-iV-substituted benzothiazoles 113 from amines, carbon disulfide, and 2-haloanilines (Scheme 5.75) [78]. The first step in this process is the reaction between amine and carbon disulfide in the presence of bases to form dithiocarbamate salt A. Then, the in situ-generated A undergoes... 

Classically, perhaps the most widely used method for the preparation of isothiocyanate involves the reaction of amines with carbon disulfide in the presence of a base such as ethanolic aqueous ammonia or sodium hydroxide to form the appropriate salt of a dithiocarbamate. The conversion of a dithiocarbamate to an isothiocyanate may be carried out by a variety of reagents such as copper sulfate, ferrous sulfate, zinc sulfate, or lead nitrate. A procedure involving the use of lead nitrate for the general preparation of isothiocyanates has been described. This reaction involves the reactions shown in Eqs. (15) and (16). 

Chemical Properties The formation of salts with acids is the most characteristic reaction of amines. Since the amines are soluble in organic solvents and the salts are usually not soluble, acidic products can be conveniendy separated by the reaction with an amine, the unshared electron pair on the amine nitrogen acting as proton acceptor. Amines are good nucleophiles reactions of amines at the nitrogen atom have as a first step the formation of a bond with the unshared electron pair of nitrogen, eg, reactions with acid anhydrides, haUdes, and esters, with carbon dioxide or carbon disulfide, and with isocyanic or isothiocyanic acid derivatives. 

Similarly, carbon disulfide and propylene oxide reactions are cataly2ed by magnesium oxide to yield episulftdes (54), and by derivatives of diethyUiac to yield low molecular weight copolymers (55). Use of tertiary amines as catalysts under pressure produces propylene trithiocarbonate (56). 

Other components in the feed gas may react with and degrade the amine solution. Many of these latter reactions can be reversed by appHcation of heat, as in a reclaimer. Some reaction products cannot be reclaimed, however. Thus to keep the concentration of these materials at an acceptable level, the solution must be purged and fresh amine added periodically. The principal sources of degradation products are the reactions with carbon dioxide, carbonyl sulfide, and carbon disulfide. In refineries, sour gas streams from vacuum distillation or from fluidized catalytic cracking (FCC) units can contain oxygen or sulfur dioxide which form heat-stable salts with the amine solution (see Fluidization Petroleum). 

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