Dithiocarboxylic acids amines

Dithiobenzoic acid metal complexes, 2, 646 colours, 2, 646 Dithiobiuret metal complexes, 2, 640 Dithiocarbamates chelating resins mineral processing, 6,826 Dithiocarbamic acid metal complexes, 2,585 amine exchange, 1,428 photographic emulsions, 6,98 nickel poisoning, 6,768 tellurium(Il) complexes photothermography, 6,121 Dithiocarbazic acid metal complexes, 2,803 Dithiocarbimic acid metal complexes, 2,588 Dithiocarbimic acid, cyano-metal complexes, 2,808 Dithiocarboxylic acids metal complexes, 2,646 Dithiodiacetic acid metal complexes, 2, 806 Dithiodiketones... 

Compound 96 reacts with SR-, with ring cleavage and loss of sulfur, to form the methyl ester of the 1-alkylmercaptocyclopent-l-ene 2-dithiocarboxylic acid (97). Compound 96 reacts in a similar manner with primary amines (see below). 

The addition of amine to the bicyclic salt (96) initially takes place not in position 3, but in position 5, as in the reaction with mercaptans the reaction then proceeds by the same steps to yield the ester of the 1-aminocyclopent-l-ene 2-dithiocarboxylic acid (118). This ester (118) is obtained in yields of 30-65% its structure has been confirmed by independent synthesis from 119. This reaction course is again confined to the special system 118, the homologous tetramethylene-trithionium salts yielding Schiff s bases on reaction with primary amines under the same conditions.50... 

Contrary to carboxylic acids which, under normal conditions, only give salts with amines, dithiocarboxylic acids, RCS2H, are quite reactive in nucleophilic displacement reactions. However, the compounds are unpleasant to handle and, due to their limited stability, often give only low yields of thioamides in the reaction with amines.The approach was successfully employed in the synthesis of thiobenzoyl azolides, e. g. in the formation of (7) according to equation (4). °... 

Thioacylation reactions with dithiocarboxylic acids are not limited to amines, but, employing the Mg salt, can also be carried out with hydroxylamine to give thiohydroxamic acids or with hydrazine and some substituted hydrazines to provide thiohydrazides. ... 

The reaction of CH acidic compounds with CS2 in the presence of excess base yields dianions of dithiocarboxylic acids. Starting from camphor, neutralization with HCl and addition of primary amines yields 3-oxonorbomanethiocarboxamides (11) with undefined stereochemistry (Scheme 3). ... 

Thioamide synthesis from dithiocarboxylates and amines under basic conditions gives thiols as rather unpleasant parallel products. This problem is avoided by using S-thioacylated thioglycolic acids (17), as... 

In general, thiocarbonyl halides (59) function as thioacylation reagents with a variety of nucleophiles to yield the appropriate thio derivatives (60) (Scheme 31). For example, (59) on condensation with thiols, amines, potassium cyanide or potassium thiocyanide yields the corresponding thio compounds (60). Thiolocarboxylic acids (50) characteristically acylate alcohols and amines with desulfuration (Scheme 32). Dithiocarboxylic acid esters (54b) react with organolithium or Grignard reagents to give the dithioketals (61) after treatment with an alkyl halide (Scheme 33). 

Figure 13.21. Major glucuronidation reactions involving phenols, alcohols, carboxylic acids, car-bamic acids, hydroxylamines and hydroxylamides, carboxamides, sulfonamides, various amines, thiols, dithiocarboxylic acids, and 1,3-dicarbonyl compounds.

The thioacylation of NH groups by dithiocarboxylic esters and their salts, as well as by thionocarboxylic esters, is dealt with in Section 5 of this chapter. Diphenylcyclopropenethione reacts with amines to give the cycloadducts (91), which are rearranged to the thioamides (92) when heated in benzene. Thioamides RNHC(S)CHXY are obtained from compounds with active methylene groups by reaction with A-aryldithiocarbamic acid esters, e.g. MeSC(S)NHPh, thiocarbamoyl chlorides, or C-sulphonylthioformamides,... 

Interconversion of thiono- and dithio-esters has been considered earlier (p. 179). The reaction of these compounds with amines has remained one of the most important and widely applied methods for the preparation of thioamides and related substances. This is especially true for carboxymethyl dithio-benzoates, - but other alkyl dithiocarboxylates > > - or RC(S)SSR work as well in many cases. For example, MeCSaMe reacted with amino-acids, free peptides, and peptides which were fixed to a polystyrene matrix, and the terminal A-thioacetyl amino-acid was split off by CF3CO2H to give 2-substituted thiazol-5-ones, which served to identify the -terminal amino-... 

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