Dithioformic ester

The mechanism of the Cook-Heilbron reaction between a-aminonitriles and dithioformic ester 6 proceeds via an acyclic intermediate 7, as proven by its isolation in several cases. Nucleophilic attack of the amine function on the sulfur-bearing carbon leads to the elimination of hydrogen sulphide. Cyclization of the acyclic thiacetoamide results in a five membered ring which aromatises favourably to give 5-amino-2-benzylthiazole 8. 

Dithioformate esters and 0-alkyl thioesters react with... 

By condensing the salts or the esters of either dithioformic (207) or dithiophenacetic acids with a-aminonitriles (206) 5-aminothiazoles (209), in which R] = hydrogen, benzyl and Rj = phenyl, carbethoxy, or car-bophenoxy, were obtained in fairly good yields (Scheme 108) (271). These reactions were carried out in aqueous ethereal solution at room temperature. Acyclic thioamides as intermediates in this reaction have been isolated in some cases (208). 

From molecular weight determinations by cryoscopic methods, the esters of dithioformic acid appear to have a trimeric constitution, for example, (II.CS2Me)3, and it is suggested 3 that the molecule of the acid is similarly constituted and possesses a cyclic structure with alternating carbon and sulphur atoms. 

Amino-4-naphthyl-5(p-aminophenyl) thiazoles, synthesis of, 230 orAminonitriles, condensation, with salts or esters of dithioformic and dithio-phenacetic acids, 284... 

The amino group of 4-amino-3-pyrazolin-5-ones reacts normally. Acylation occurs readily with a wide variety of acylating agents. Amides are formed by reaction with acid chlorides,50,533,984,1414,1473 acids618,984,1471 and esters in the presence of phosphorus pentoxide.1471 Thioformamides have been prepared by reaction with dithioformic acid and its salts.472,556,1374 Sulfonyl chlorides react to form sulfonamides.98,489,984,1249,1504 Chlorophosphates react with 4-amino-3-pyrazolin-5-ones to form phosphoramide derivatives.509,1498... 

Such esters have also been obtained by chlorination of bis(alkyl xanthates) [dialkyl dithio(dithioformates)].750... 

Two further reactions might be included here, since they involve modification at both carbon and sulphur. In the first reaction, dehydration of the sulphoxides 388 (R = Me or aryl R = H, Me, ethenyl or Ph) to the diethyl [(l-alkylthio)alk-l-enyl]phosphonates 389 is said to result following the action of trimethylsilyl trifluoromethanesulphonate The second reaction constitutes a new and improved synthesis of an ester of (mercap-tomethyl)phosphonic acid, and consists in the treatment of methyl (diisopropylphosphi-noyl)dithioformate with NaBH4. ... 

The formamides 16 are intermediates. Formamide (Bredereck variant of the Traube synthesis [149]), formamidine, orthoformic ester, diethoxymethyl acetate, Vilsmeier reagent (fi om DMF and POCI3) and dithioformic acid are used as formic acid derivatives. 4,5-Diaminopyrimidines can be obtained from 4-aminopyrimidines 17 by nitrosation with HNO2 followed by reduction of the nitroso compounds 18 ... 

By reducing the salts or the esters of both dithioformic and dithiophenacetic acids with a -aminonitriles, 5-aminothiazoles were achieved in better pelds [52]. These reactions have agreed in aqueous ethereal solution at ambient temperature. 

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