Facile synthesis of [1,2,4]triazino[4,3-b][1,2,4,5]tetrazepin derivatives by a one-pot reactions using 4-amino-3-hydrazinyl-6-methyl-1,2,4-triazin-5(4H)-one

4-Amino-3-mercapto-6-methyl-1,2,4-triazin-5(4H)-one 1 converted to 4-amino-6-methy-3-(methylthio)-1,2,4-triazin-5(4H)-one by methylation with methyl iodide. Controlled hydrazination of the resulting compound afforded 4-amino-3-hydrazinyl-6-methyl-1,2,4-triazin-5(4H)-one 2 as a building block, to the synthesis of some novel derivatives of [1,2,4]triazino [4,3,b][1,2,4,5]tetrazepine 3-6, by the reaction with 3-chloropentane-2,4-dione, chloro acetonitrile, 1,3-dichloroacetone, and methyl bromoacetate. This general synthetic procedure can be extended to the preparation of wide variety of tetrazepines using 1,2-bielectrophiles derivatives.