Secondary amines reactions, carbon disulfide

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 ... 

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. 

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

Titanium(IV) iodide is extremely hygroscopic. It dissolves in water with decomposition, and it fumes in air owing to hydrolysis. It forms 2 1 adducts with ammonia,7 pyridine,33 and ethyl acetate.34 With excess ammonia it undergoes ammo-nolysis to give ammonobasic titanium(IV) iodides.7 Analogous aminolysis reactions occur when titanium(IV) iodide is treated with an excess of primary or secondary amine.36 Titanium(IV) iodide is sparingly soluble in petroleum ether, moderately soluble in benzene, and even more soluble in chlorinated hydrocarbons and carbon disulfide. At elevated temperatures it... 

Dithiocarbamates have been prepared by the reaction of carbon disulfide with primary or secondary amines. The addition of DMF, cesium carbonate and a sulfonamide to the crude dithiocarbamate, give di-, tri- and tetra-substituted thioureas in 65-76% yields (Scheme 41).121... 

For example, polymers having hydroxyl end groups can be prepared by reaction of polymer lithium with epoxides, aldehydes, and ketones III-113). Carboxylated polymers result when living polymers are treated with carbon dioxide (///) or anhydrides (114). When sulfur (115, 116), cyclic sulfides (117), or disulfides (118) are added to lithium macromolecules, thiol-substituted polymers are produced. Chlorine-terminus polymers have reportedly been prepared from polymer lithium and chlorine (1/9). Although lithium polymers react with primary and secondary amines to produce unsubstituted polymers (120), tertiary amines can be introduced by use of p-(dimethylamino)benzaldehyde (121). 

Thirty-nine different dithiocarbamates have been efficiently prepared through a one-pot reaction of an aliphatic primary or secondary amine, carbon disulfide and an alkyl halide (Figure 2.16). " Typically, all reagents were liquids and the mixture slowly solidified upon reaction. Therefore, although the reaction does not use solvents, the reagents are probably acting as the solvent in this procedure. Additionally, the reactions were quenched with water and extracted with ethyl acetate, so solvent was used. Nevertheless, this is an excellent synthetic method for the preparation of S-alkyl dithiocarbamates, which are useful compounds for the pharmaceutical and agrochemical industries. 

Polymer-bound reagents have also been used. The synthetically important Weinreb amides [RCON(Me)OMe, see 16-82] can be prepared from the carboxylic acid and MeO(Me)NH HCl in the presence of tributylphosphine and 2-pyridine-A -oxide disulfide. Di(2-pyridyl)carbonate has been used in a related reaction that generates amides directly. The reaction of a carboxylic acid and imidazole under microwave irradiation gives the amide. Microwave irradiation of a secondary amine, formic acid, 2-chloro-4,6-dimethoxy[l,3,5]tria-zine, and a catalytic amount of DMAP (4-dimethylaminopyridine) leads to the formamide. ° Ammonium bicarbonate and formamide converts acids to amides with microwave irradiation. Lactams are readily produced from y- or 8-amino acids, for example. 

Recently, Ma et al. developed a three-component reaction for the synthesis of 2-A -substituted benzothiazoles 107 via the copper-catalyzed coupling of 2-iodoanilines, carbon disulfide, and secondary amines (Scheme 3.56) [149]. In these reactions, the condensation of CS with an amine in the presence of a base generates dithiocarbamate salts XXXV, which undergo coupling with 2-iodoanilines to give XXXVI and subsequent intramolecular condensation and elimination to afford the substituted benzothiazoles 107. 

Although bis(disubstitutedthiocarbamoyl) disulfides (thiuram disulfides) have been known for some time, the synthesis of the titled disulfides have never been reported. In 1977 D Amico and Morlta (60) reported that the reaction of thiocarbamoylsulfenamides (61-62) with carbon disulfide in methyl alcohol afforded either the symmetrical or previously unknown asymmetrical thiuram disulfides in 87 to 98% yield. The thiocarbamoylsulfenamides (61-62) were prepared by the oxidative condensation of a salt of a dlsubstituteddithiocarbamic acid and a secondary amine or by the reaction of the above salt with a N-chloro secondary amine. 

To a ice cold mixture of organic halide (2 3 mmol) and carbon disulfide (3 6 mmol) was added secondary amine (1 6 mmol) and stirred at 0 °C for 30 min, then warmed to room temperate and stirring was continued tmtil the reaction was complete (monitored by TLQ. The reaction was quenched by addition of water and was extracted with ethyl acetate, dried over anhydrous sodium sulfate, and evaporated to give almost pure product. Further purification in some cases was done by silica gel column chromatography eluted with petroleum ether and ethyl acetate or recrystallized to afford the pure dithiocarbamate 4. All the products were characterized by spectral studies and data were compared with literature values. 

Aminothiophenes can also be obtained from carbon disulfide-derived intermediates. For example, one of the methylthio groups of ketene dithioacetal 57, obtained from pentane-2,4-dione as shown, can be displaced with a secondary amine and the thiophene ring constructed by reaction with, for example, ethyl thioglycolate for final ring closure (Scheme 79) [127]. 

Dithiocarbamate building blocks are reported in [214] to form coordination capsules 809-820 (Scheme 4.206) with appropriate octahedral transition metal cations, such as cobalt and iron(III) ions, by one-pot reaction of the corresponding secondary amine, carbon disulfide, organic (tri-ethylamine), or inorganic (KOH) base and the... 

Dithiocarbamates are generally easily prepared, resulting from the reaction of carbon disulfide with a secondary amine in the presence of base (Eq. 1). Reactions are usually carried out in water, methanol or ethanol, and sodimn or potassium hydroxides typically serve as the base. Some preparations recommend that the reaction be carried out at low temperature, but in most cases room temperature suffices. Reactions are typically rapid and proceed cleanly and in high yield. 

The secondary reduction of the terminal radical by Sml2 generates samarium alkyl species which are suitable for classical organometallic reactions, e.g. protonation, acylation, reactions with carbon dioxide, disulfides, diselenides, or the Eschenmoser salt. A broad variety of products is available (hydroxy-substituted alkanes, esters, carboxylic acids, thioethers, selenoethers, tertiary amines) by use of the double-redox four-step (reduction-radical reaction-reduction-anion reaction) route (Scheme 20) [73]. 

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