Sugar amines, isothiocyanation

Thioureas are most commonly prepared from reaction of isothiocyanates with amines. Also there are some reports on reactions of anime or carbodiimides with several thionating reagents. AA -Disubstituted thioureas bearing double NH groups have been developed as sensors, and as catalysts because of their hydrogen bonding ability. A,A -Disubstituted thiourea-linked sugar chains have been prepared by the reaction of isothiocyanate with amine. 

In a series of publications and patents,63 64 66"79 Wieniawski and coworkers reported the results of investigations of the reaction of sugar isothiocyanates with amines and various substituted hydrazides of heterocyclic acids. The reaction of isothiocyanate 2 with 2,6-diaminopyridine 81 was described,63 and the formation of dithioureide 82 as the sole product was observed. The... 

Coupling of Sugar Isothiocyanates with Amine Nucleophiles... 

In carbohydrate chemistry, the most described method for the preparation of saccharidic thionocarbamates involves preliminary introduction of the amine function on a partially or non-protected saccharidic template. The condensation of amino sugars with carbon disulfide or thiophosgene leads to cyclization in 1,3-oxazolidine- or l,3-oxazine-2-thiones. This reaction involves the formation of an intermediate isothiocyanate, which reacts further with a 3- or y-located hydroxyl group. The viability and facility of this process depends on the saccharidic ring size and the inherent strain. Some major rules can be put into light from the cases studied 30... 

Ogura and Takahashi18,19 detailed the reaction of the sugar isothiocyanates 2, 30, 31, and 32 with ammonia and amines, as well as with various classes of hydrazines. The reaction of sugar isothiocyanates with various classes of amines,44"62 hydrazines,63 72 and hydrazides has been reported by... 

The new examples reported include the preparation of antiviral, antibacterial, and antitumor agents by coupling sugar isothiocyanates and such biologically active amines as triazole derivatives,195 mitomycin,196 isothia-zolopyrimidines,40 and also platinum compounds.197 Other A -nuclcophiles such as hydrazine,37 isothiourea,198 and guanidine derivatives199 have been similarly coupled to sugar isothiocyanates. 

The equilibrium mixture of these two compounds can be directly used for the preparation of sugar-derived thioureas by coupling with alkyl and aryl amines [47]. This was the first example in the literature of a thio carbamate acting as a latent isothiocyanate for the synthesis of thioureas. 

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