Two-component,one-pot synthesis of pyrimido[1,2-b] [1,2,4,5]tetrazines

Derivatives containing the cyclohepta4′,5′thieno2′,3′:4,5]pyrimido1,2-b]1,2,4,5]-tetrazin-6-one system were prepared from the reaction of 3-amino-2-thioxo-1,2,3,5,6,7,8,9-octahydro-4H-cyclohepta4,5]thieno2,3-d]pyrimidin-4-one (5) or its 2-methylthio derivative 6 with hydrazonoyl chlorides 9. The mechanism of the studied reactions has been discussed and the biological activity of the isolated products has been evaluated.