Thioamides and related compounds

Most of the papers reporting on n.m.r. spectroscopic investigations of thioamides and related compounds have already been mentioned in the section dealing with restricted rotation phenomena. In addition, Walter and Becker have reported on the anisochrony of the isopropylic methyl groups in o-di-isopropylthioanilides (373). This phenomenon, which is a... 

Synthesis from Thioamides and Related Compounds. Type B, CgHs—N-—C—S.) The action of a large excess of thionyl chloride on substituted thioureas of type (22) (incorporating a jS-hydroxy-group in their Aralkyl group) produces 2-aminobenzothiazole derivatives (23) preferentially, rather than thiazolines (24) or oxazolines. Thionyl chloride, like sulphuryl... 

Thioamides and Related Compounds. Thioamides are the most stable thiocarbonyl compounds and have been prepared, for a century, from amides and P4S10 under rather drastic conditions. However, even for this purpose LR has turned out to be a superior reagent. High yields are obtained for all types of thioamides and -lactams including the elusive unsubstituted acrylo-thioamide (eq 18) and thioformamides or thioamides bearing sensitive substituents such as NO2, Z-NH, or OH (eq 19). ... 

Thioamides and Related Compounds. Thioamides are the most stable thiocarbonyl compounds and have been prepared, for a century, from amides and P4S10 under ratber drastic conditions. However, even for this purpose LR has turned out to be a superior... 

Derivatives of amides, thioamides, sulfonamides, and related compounds... 

Thiourea and related compounds like thioamides have been studied polaro-graphically in alcoholic buffered media. Being cathodically reduced, benzotri-azepine (22) undergoes a ring contraction affording the corresponding quinazoline (23) (Eq. 25) [194,195]. 

Primary and secondary amides and thioamides react with alkyl chlorofoimates with loss of CO2 or COS, forming iminium chlorides (82 equation 52). In some cases this method is complementary to the Pinner imido ester hydrochloride synthesis. The iminium salt (83 Scheme 6) formed by action of ethyl chloroformate on DMF is labile and decomposes rapidly to ethyl chloride. If the reaction is performed in the presence of NaBp4, the iminium salt (85) is isolable. Aryl chlorofoimates react in the same fashion with DMF or DMA, but in these cases the aryloxymethyleneiminium compounds are fairly stable, so this reaction is an important method for the preparation of compounds of this type. - Succinic acid monoamides, phthalic acid monoamides and related compounds are cyclized to iminium salts (86 equation 53) by treatment with acetic anhydride and HC104. ° With the aid of trifluoromethanesulfonic anhydride lactams and amides can be converted to dication ether salts (87) and (88 Scheme 7).22i.222... 

The C-2/C-4 addition of conjugating substituents (e.g., thiochalcone and related compounds) - or electron-donating substituents (e.g., j3-enaminothioketones, " -thioaldehydes, -dithioesters, and a,/8-un-saturated dithioesters or thioamides ) to the a,/3-unsaturated thiocar-... 

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-... 

There is an enormous literature on thiocarbonyl compounds, due in part to the technical and industrial importance of many of them, including thioamides, thioureas, xanthates, dithiocarbamates and so forth. An excellent, and recent, general review is available.107 There are also specialized reviews germane to the present chapter Griffin, Woods, and Klayman2 discussed the use of thioureas in the synthesis of heterocycles the preparation of thiazoles from thioamides is included in a three-part volume on Thiazoles 108 the use of carbon disulfide in the synthesis of trithiones and related heterocycles has been reviewed by Mayer109 and Huisgen110 has reported numerous examples of 1,3-dipolar cycloadditions in which carbon disulfide was used. 

Thioamides, Thioureas and Related Selenium and Tellurium Compounds... 

Dithiophosphoric and dithiophosphinic acids can also react with organic compounds containing multiple carbon-nitrogen bonds, often under very mild conditions, to give thioamides and other related compounds (e.g., Equation 82).163... 

The reductive Raney nickel desulfurisation of thioamides is used routinely in the alkaloid series. It proved efficient for the synthesis of Vinca alkaloid related compounds [21], a vinblastine precursor [127], 19-hydroxytubo-taiwine [170], and (-)-monomorine [171]. 

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