Savytskyi P. Cyclization of 1-hetaryl-4-aryl(alkyl)thiosemicarbazides by treating with methyl iodide and dicyclohexylcarbodiimide

This work is devoted to the study of intramolecular electrophilic cyclization of a 1-hetaryl-4-aryl(alkyl)thiosemicarbazides under the action of methyl iodide - sodium acetate and dicyclohexylcarbodiimide. This study has given results, which have revealed factors that affect on regiochemistry of this cyclization and allowed to make a comparative analysis of the two aforementioned cyclization reagents. By cyclization of 1-hetaryl-4-aryl(alkyl)thiosemicarbazides have been received new 1,2,4-triazoloheterocycles. It has been established, that the direction of cyclization of thiosemicarbazides depends on the nature of internal nucleophile and the character of cyclization reagents. For all of the obtained 1,2,4-triazoloheterocycles has been studied the possibility of Dimrot's rearrangement.