4-Mercaptoimidazolium hydroxide inner

Hydroxy-THISs add regioselectively to the C=N bonds of isocyanates or isothiocyanates. The initially formed cycloadducts eliminate carbonyl sulfide with formation of 4-hydroxy- or 4-mercaptoimidazolium hydroxide inner salts (21) (Scheme 21). 4-Hydroxyimidazolium hydroxide... 

The 5-methylthiothiazolium salts react with methylamine to give 4-mercaptoimidazolium hydroxide inner salts (25) and with aniline to give 26 (Scheme 24) (32). 

Besides being useful precursors to pyrroles pyridine-2-ones -4-ones, -4-thiones. and -4-imines 4-alkylidene-dihydropyridines thiophenes 1,2,4-triazoles thiapyrane-2-thiones, isoquinoline-3-ones isoben-zothiophenes and 4-mercaptoimidazolium hydroxide inner salts, mesoionic thiazoles are potentially useful in the construction of molecules with herbicidic (39). central nerve stimulating, and antiinflammatory properties (40,41). Application in dye synthesis has likewise been reported (42). 

Maionic add, in monomethine thiazolo-cyanine synthesis, 52 4-Mercaptoimidazolium hydroxide inner salts, from 5-hydroxy THISs, 11 from 5-mercaptothiazolium salts, 12 2-Mercaptoselenazoles. substituted in 4-positions, photographic emulsion, 237... 

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