Chlorothioformyl chloride

In an examination of the reactions of a-ureido nitrogen heterocycles with chlorothioformyl chloride it was found that (607) reacted to give (608) in yields of 12-63% depending on the nature of R. The products were rather unstable and decomposed with loss of methyl isocyanate and sulfur both on heating and on long standing at room temperature (73JOC1578). 

I -Chloro-1 -phenyliminomethanesulphenyl chloride reacts without external heat with aminoazines to form a fused thiadiazole ring. Chlorothioformyl chloride... 

The condensation of chlorothioformyl chloride and l-alkyl-3-arylureas occurs in boiling benzene and affords 4-alkyl-2-aryl-l,2,4-thiadiazolidine-3,5-diones (1 ) in high yield. The alkylamino group of the ureas is thought to be attacked preferentially, leading to the formation of intermediates of type 168.151... 

Condensation of bis(alkoxymethyl)carbodiimides and chlorothioformyl chloride in boiling benzene occurs with loss of one mole of alkoxymethyl chloride, and production of 2-alkoxymethyl-3-chloro-A3-l,2,4-thiadiazolin-5-ones (176).160... 

Condensed ring systems incorporating 1,2,4-thiadiazole are formed when a heterocyclic compound (178) functioning as the amidine is condensed with chlorothioformyl chloride (179) or ethyldithiocarbonyl chloride (180) the scope of this synthesis is very wide indeed. 

The addition of chlorothioformyl chloride to a-amino-N-heterocycles can clearly take place in the opposite sense, the sulfur atom appearing adjacent to the exocyclic nitrogen of the starting material. This occurs when 2-aminothiazole or 2-amino-A2-thiazoline react in ethanol-free chloroform, resulting in thiazolo[2,3-c]-l,2,4-thiadiazol-3-one (186) or its 5,6-dihydro analog. The structure of the latter has been confirmed by X-ray analysis. 2-Amino- (and 4-amino-2,6-dimethyl)pyrimidine similarly afford 1,2,4-thiadiazolo[4,3-a]pyrimidin-3-one (187, R = H, 34%) and 5,7-dimethyl-l,2,4-thiadiazolo[4,3-c]pyrimidin-3-one (39%), respectively. Possible mechanisms of the reactions have been discussed.164... 

X = NCHO) <78H(ii)3i3>. Reaction of 2-amino-5-chloropyridine with chlorothioformyl chloride (ClSCOCl) gave (139 R = Cl, X = O) <73JOC1575>. 

Thiazolo[2,3-c][l,2,4]thiadiazoles.—The condensation of a-amino-N-heterocycles with chlorocarbonylsulphenyl chloride (chlorothioformyl chloride, ClCOSCl) can give rise to either a 3,4- or a 2,3-fused 1,2,4-thiadiazolone (see Vol. 3, p. 684). The former reaction occurs when 2-aminothiazole or 2-amino-A -thiazoline is condensed with this reagent in chloroform, affording thiazolo[2,3-c][l,2,4]-thiadiazol-3-one (79) or the 5,6-dihydro-analogue, the structure of which has been confirmed by X-ray analysis. For another synthesis of this class see above. ... 

A general synthetic route to N-bridgehead condensed heterocyclic structures incorporating a 1,2,4-thiadiazole ring consists of the interaction of an a-amino-heterocyclic compound with chlorothioformyl chloride (84) or ethyldithiocarbonyl chloride (85). The reaction is widely applicable, as shown. 

Aminothiazoles (86) react with chlorothioformyl chloride (84) to give tars, from which 2H-thiazolo[3,2-l>][l,2,4]thiadiaz(d-2-one (87) is isolable in 3% yield the use of ethyldithiocarbonyl chloride (85) raises the yields to 25%. ... 

The interaction of chlorothioformyl chloride and comparable heterocyclic methylureas (92) proceeds partly with identical results. Loss of methyl isocyanate from (92) yields the parent amine (93) and thence the condensed bicyclic products (97), as described immediately above. Simultaneous direct condensation of the urea (92) affords, by way of the hypothetical intermediate (94), the fused thiatriazepinediones (96) as well as 1,2,4-thiadiazoli-dinediones (95), generally in moderate yields. The observations on record are too varied to be adequately summarized examples of the structures obtained are 2H-thiazolo[3,2-b][l,2,4,6]thiatriazepine-2,4(3H)-diones (98) and 2-(thiazol-2-yl)-4-methyH,2,4-thiadiazolidine-3,5-diones (99). ... 

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