Substituted 2-amino-1,3,4-thiadiazines: a novel solid-phase approach

A novel and facile strategy for synthesis of substituted 2-amino-1,3,4-thiadiazines on solid support is described. Resin bound isothiocyanate prepared from an immobilised primary amine and di-(2-pyridyl)thionocarbonate was reacted with hydrazine hydrate to form the intermediate thiosemicarbazide. Further reaction with a range of α-bromoketones followed by mild acidic cleavage from the solid support released the substituted 2-amino-1,3,4-thiadiazines in respectable yields and excellent purity.