International Journal of Heterocyclic Chemistry, Vol. 4, No. 1, pp. 20-29© Ahvaz Branch, Islamic Azad University 20 Microwave assisted synthesis of [4, 5-e] [1, 3, 4]thia- diazin-7-yl] hydrazine Derivatives Javad Azizian , 1 Ramin Miri , 2 Mohammad Kazem Mohammadi 1 1 Factually of Science, Islamic Azad University, Science and Research Branch, Tehran, Iran. Fax : +98-7126224402 . E – mail : mohammadi@iauahvaz.ac.ir 2 Medicinal & Natural Products Chemistry Research Center , Shiraz University of Medical Sciences , Shiraz , Iran 3 Factually of science , Ahvaz Branch Islamic Azad University , Ahvaz , Iran . Abstract - New pyrimido [4, 5-e] [1, 3, 4]thia- diazin-7-yl] hydrazines were synthesized via the cyclocondensation of alkyl-2-phenylhydrazinecarbodithioates as a binucleophile with 5-bromo-2,4-dichloro-6-methylpyrimidine as a bielectrophile , and replacement of C-7 chloro atom by hydrazine in ethanol as the solvent . This method has advantages over methods currently described in the literature for the construction of such heterocyclic ring systems. Keywords: Heterocyclization ; 5-Bromo-2,4-dichloro-6-methylpyrimidine ; Pyrimido[4,5- e][1,3,4]thiadiazine ; Binucleophile ; Bielectrophile .