Disulfides from amines

Thioureas. Thioureas (11) are typically made from primary amines and carbon disulfide. The amine can be ethylamine, butylamine. 

The direct electrosynthesis of S—N bonds from disulfides and amines has been shown to occur through a reaction of the amine with the oxidized disulfide being a strong electrophile. In contrast to the results, the cross-coupling of phthahmide (16) with disulfide does not proceed in a direct electrolysis. However, the electrosynthesis of sulfenimides (17) can be achieved by a [Br]" "-mediated cross-coupling reaction of imides with disulfides (Scheme 7). The electrolysis of a mixture of (16) and dicyclohexyl disulfide in an MeCN-NaBr-(Pt) system affords... 

Isothioureas can be prepared on insoluble supports by S-alkylation or S-arylation of thioureas (Entry 7, Table 14.6). Further methods for the preparation of isothioureas on insoluble supports include the N-alkylation of polystyrene-bound, A/,/V -di(alkoxy-carbonyl)isothioureas with aliphatic alcohols by Mitsunobu reaction (Entry 7, Table 14.6) and the addition of thiols to resin-bound carbodiimides [7]. Resin-bound dithio-carbamates, which can easily be prepared from Merrifield resin, carbon disulfide, and amines [76], react with phosgene to yield chlorothioformamidines, which can be converted into isothioureas by treatment with amines (Entry 8, Table 14.6). The conversion of support-bound a-amino acids into thioureas can be accompanied by the release of thiohydantoins into solution (see Section 15.9). The rate of this cyclization depends, however, on the type of linker used and on the nucleophilicity of the intermediate thiourea. 

PROTECTING GROUPS - Cyclic imide disulfides from primary amines can be prepared by the scheme below. Treatment with mercaptoethanol under very mild conditions gives back the starting amine. 

Sym. disulfides from halides with simultaneous reduction of nitro compounds to amines... 

The use of molybdenum compounds in organic synthesis has attracted greater attention. Thus, molybdenum hexacarbonyl has been used in various reactions, such as the preparation of disulfides from sulfonyl chlorides, the alkylation of aryl derivatives, and the synthesis of 4-quinazolones from amines Oxygen has been replaced by fluorine with molybdenum hexafluoride. Molybdenum pentachloride in combination with hydroperoxides has served as oxidant Chelates of MoOg " have been investigated as catalysts for oxidations with molecular oxygen 2,2-Dichloro-7-butyrolactones have been prepared from olefins and methyl trichloracetate with cyclopentadienylmolyb-denum tricarbonyl dimer as catalyst ... 

Both ( )- and (Z)-allyl dithiocarbamates have been stereoselectively prepared in high yields from acetates of MBH adduets in catalyst-free one-pot three-component coupling reactions of carbon disulfide and amine in water under a mild and green procedure (Scheme 3.152). The reaction pathway involves the nucleophilic displacement (-S n2 ) of MBH acetates by dithio-carbamate anions. The utility of these allyl dithiocarbamates has been demonstrated in the synthesis of 3,5-dibenzyl-l,3-thiazines derivatives 344 and 345 (Scheme 3.153). ... 

Active hydrogen compounds such as alcohols, thiols, amides, urethans, and sulfonamides can be alkylated by N-vinyl-amides, -urethans, or -sulfonamides in high yields. A one-step conversion of ar. nitro compounds to isocyanates has been reported Aliphatic isothiocyanates can be prepared from amines and carbon disulfide with dicyclohexylcarbodiimide under remarkably mild conditions... 

Thiolcarbamic acid esters from amines and disulfides... 

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... 

Several authors have exploited MCRs in water starting from carbon disulfide, primary amines and carbon dielectrophiles for the construction of 1,3-thiazole derivatives. Representative examples are summarized in Scheme 1.19 and include ... 

Sulfenamides can be synthesized by a metal-assisted reaction with disulfides and amines (eq 13). Conjugated dienols can be synthesized in a highly chemo-, regio-, and stereoselective manner from vinylic halides and allylic alcohols (eq 14). Silver acetate (or silver carbonate) and a catalytic amount of palladium(II) acetate in DMF are the preferred conditions. The reaction is very attractive because it requires only one functionalized alkene reactant and the addition of the vinylic group only occurs at the terminal carbon of the aUyUc alcohol. 4... 

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... 

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... 

General Reaction Chemistry of Sulfonic Acids. Sulfonic acids may be used to produce sulfonic acid esters, which are derived from epoxides, olefins, alkynes, aHenes, and ketenes, as shown in Figure 1 (10). Sulfonic acids may be converted to sulfonamides via reaction with an amine in the presence of phosphoms oxychloride [10025-87-3] POCl (H)- Because sulfonic acids are generally not converted directiy to sulfonamides, the reaction most likely involves a sulfonyl chloride intermediate. Phosphoms pentachlotide [10026-13-8] and phosphoms pentabromide [7789-69-7] can be used to convert sulfonic acids to the corresponding sulfonyl haUdes (12,13). The conversion may also be accompHshed by continuous electrolysis of thiols or disulfides in the presence of aqueous HCl [7647-01-0] (14) or by direct sulfonation with chlorosulfuric acid. Sulfonyl fluorides are typically prepared by direct sulfonation with fluorosulfutic acid [7789-21-17, or by reaction of the sulfonic acid or sulfonate with fluorosulfutic acid. Halogenation of sulfonic acids, which avoids production of a sulfonyl haUde, can be achieved under oxidative halogenation conditions (15). 

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). 

In these papers, the carboxylic acid to be protected was a stable, unsubstituted compound. Harsh conditions were acceptable for both formation and cleavage of the amide. Typically, a simple secondary amide is very difficult to cleave. As the pKa of the conjugate acid of an amide decreases, the rate of hydrolysis of amides derived from these amines increases. The dimethylamide of a cephalosporin was prepared as follows using 2,2 -dipyridyl disulfide. ... 

Amine A-oxides 56 were reduced to amines by carbon disulfide (62CPB969). Tire proposed mechanism involved the formation of amines and dithiiranone (57) from the initial adducts 58 the latter is finally hydrolyzed to CO2 and H2S2 (82BCJ3000). 

Figure 12.12 Coupled SEC-RPLC separation of Plioflex rubber stock (a) SEC (b) RPLC ti ace of fraction 1, Wingstay 100 (Eive-peak pattern is representative of diarylphenylenedi-amine isomers) (c) RPLC ti ace of fraction 2, mixed disulfide and MBTS (2,2 -thiobis (ben-zothiazole)). Obtained under the same conditions as given for Eigure 12.11. Reprinted from Journal of Chromatography, 149, E. L. Johnson et al, Coupled column chromatography employing exclusion and a reversed phase. A potential general approach to sequential analysis , pp. 571-585, copyright 1978, with permission from Elsevier Science.

The carbanion 5, formed from V,V-diethyl-5-phenyl-3//-azepin-2-amine (4) with potassium amide in liquid ammonia, or with lithium 2,2,6,6-tetramethylpiperidide in tetrahydrofuran, is thiolated by dialkyl or diaryl disulfides to yield 3-(alkylsulfanyl)-3//-azepines, e.g. 6.38... 

Considerably less is known about the chemistry of palladium and platinum 1,1-dithio complexes. Of late, there has been only one report that dealt with the synthesis of a large number of palladium dithiocar-bamates 392). Twenty-five yellow palladium dithiocarbamate complexes were obtained by reaction of PdCla with NaR2dtc in methanol solution. Several other reports have appeared in which a few dithiocarbamate complexes of palladium were synthesized. Thus, the novel [Pd (OH)2dtc 2], which is soluble in water, was isolated 393). The synthesis of optically active palladium(II) complexes of AT-alkyl-a-phen-ethyldithiocarbamates, similar to (XXIV), via the reaction between the optically active amine, CS2, and PdCl2, has been described. From ORD and CD spectra, it has been established that the vicinal contribution of a remote, asymmetric carbon center could give rise to optical activity of the d—d transitions of palladium 394). Carbon disulfide has been shown to insert into the Pt-F bond of [PtF(PPh3)3]HF2, and X-ray studies indicated the structure (XXIX). 

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 ... 

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