Mercaptothiazoles, formation

The reaction of a-aminonitriles and carbon disulphide was stated by Cook and Heilbron to give 5-amino-2-mercaptothiazoles however, they later found that the same reaction with aminoacetonitrile was more complex. When aminoacetonitrile sulphate in ethanolic solution was treated with carbon disulphide, the dithiodicarbamate 9 was formed. Benzylation was then carried out treatment of the resulting ester 10 with phosphorus tribromide with subsequent loss of water gave 5-amino-2-benzylthiothiazole 11 in a quantitative fashion. The rapid reaction was thought to be the first example of the formation of a 5-aminothiazole from an a-aminoamide. 

Bromothiazole (1) reacts with thiourea in alcohol to yield a mixture of dithiazolyl monosulfide (2) and A-4-thiazoline-2-thione (3) (Scheme 1) (4-6). Treatment of 2-bromo-4-methvlthiazole with potassium hydrogen sulfide in alcohol is reported to result in the formation of bis(4-methyl-2-thiazolylisulfide (7). which probably results from the reaction between the initially formed 2-mercaptothiazole and the initial 2-bromo-4-methylthiazole. 

Mercaptothiazoles, as accelerators in vulcanization of rubber, 260 alkylation of, 266 mechanism of formation, 269 from o bromoalkynes, 265 oxidation of, 172... 

In addition to the syntheses described above, many other processes for the use of formaldehyde in the production of dyes and dy e intermediates are described in the patent hterature. Recent patents,for example, includethe production of benzene-soluble azo dyes by coupling diazotized arj lamines with aromatic hydroxy compounds plus formaldehyde , preparation of vat dyes by condensation of formaldehyde with ST-dihy di O-l,2,T,2 -anthra-quinone azities , synthesis of nitroso dy es by. reacting formaldehyde viith p-X-alky laminonitrosoben2ene del i atives, formation of thiazole dyes from mercaptothiazoles, primary amines, and foimaldehyde , production of diphenyimethane intermediates , etc. 

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