A Facile One-Pot Synthesis of 1,4,7,8,9,10-Hexahydro-6H-[1]- benzothieno[2', 3', :4,5]pyrimido[1,2-b][1,2,4,5]tetrazin-6-ones

1,4,7,8,9,10-Hexahydro-6H-[1]benzothieno[2’,3’:4,5]pyrimido[1,2-b][1,2,4,5]tetrazin-6-ones were prepared via reaction of 2,3,5,6,7,8-hexahydro-3-amino-2-thioxo[1]benzothieno[2,3-d]- pyrimidin-4(1H)-one or its 2-methylthio derivative with hydrazonoyl halides in ethanol in the presence of triethylamine. Some of the products were screened for their biological activity.