Thiocarbamoyl salt

Two modifications of the well-known benzothiazole preparation have been employed to prepare unusual heteropoly cycles. Konig et al.ils treated l-thiocarbamoyl-l,2,3,4-tetrahydroquinoline (236) with bromine in chloroform to give the thiazolo[3,4,5-J,i]quinoline derivative 237. In a process which requires disruption of the resonance stabilization of the pyridine ring, Harris416 reported that treatment of l-(2-pyridyl)-2-thiourcas with sulfuryl chloride or with bromine gives the hydrohalide salts of 2-imino-2//-[l,2,4]thiadiazolo[2,3-a]pyridines (238). 

It has been shown also that both thiocarbamoylimidazoles 147 and 148 can react with sodium azide. These compounds were successfully used to prepare heterocycle-peptide conjugates as peptidomimetics. A-Terminal aminothiatriazole modified amino acids have been synthesized using two methods (Scheme 35). To prepare monosubstituted aminothiatriazoles 151 the amino acid derivatives were converted into the thiocarbamoyl imidazoles of type 147 that can react with azide ion to form the thiatriazole ring. On the other hand, for the synthesis of disubstituted amino acid derivatives of 1,2,3,4-thiatriazoles 153 and 155 the activation of the thiocarbonyl group via a salt of type 148 was required. The reaction conditions and the yields of thiatriazoles 151, 153, and 154 prepared by this approach are shown in Scheme 35. 

Thiazetidines may be prepared by alkylation of the sodium salts obtained conveniently by thiocarbamoylation of the sulfonamides 191 with isothiocyanates in the presence of sodium hydride in DMF. Alkylation with bromo-chloromethane or dibromomethane yields the substituted 2-imino-l,3-thiazetidines 41 <2002SUL105>. 

Thiocarbamoylation of malonic acid derivatives with phenyl isothiocyanate gives the sodium salts 193 which are not isolated. Alkylation of these salts in situ using dibromomethane or bromochloromethane yields the 1,3-thiazetidine derivatives 40 (Scheme 63) <2005MI499>. 

Dithiocarbamic esters can generally be obtained easily by alkylation or arylation of the corresponding dithiocarbamic salts 792-798 other methods are addition of thiols to isothiocyanic esters,792 treatment of chlorodithio-formic esters with amines,792 and reaction of thiocarbamoyl chlorides with thiolates.786... 

Thiazyl halides, aromaticity of, 357 Thienotropylium cation, salts of, 65 Thiocarbamoyl azides, 264 Thiohydrazides, 1,2,3,4-thiatriazoles firom, 265... 

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,... 

Mercapto-1,2,5-thiadiazoles are obtainable by a procedure based on the rearrangement of thiono- into thiol-carbamates. It comprises the thioacyla-tion of (226) with thiocarbamoyl chloride, then rearrangement of the resulting thionocarbamate (227) at 130 C into (228), followed by hydrolysis. The resulting labile thiol is stabilized as the potassium or mercury salt (229), or as the 4-methoxycarbonylmethyl derivative (230). The i.r. spectrum (in... 

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