Synthesis and biological activity of new functionalised cyclohepta[4,5]-thieno[2,3- d ][1,2,4] triazolo[4,3- a ]pyrimidin-5-ones

Various functionalised derivatives of 5 H-cyclohepta[4,5]thieno[2,3- d][1,2,4]triazolo[4,3- a]pyrimidin-5-one were synthesised via reaction of hydrazonoyl halides (1) with either 1,2,3,5,6,7,8,9-octahydro-2-thioxo-4 H-cyclohepta-[4,5]thieno[2,3- d]pyrimidin-4-one (2) or its methylthio derivative (3). The mechanism and the regioselectivity of the studied reactions are investigated and discussed.