“…According to the published procedures, the starting aminothiophene esters 1a [21] and 1b [22,23] were prepared using sulfur element, ethyl cyanoacetate, morpholine, and cycloketone or ethylacetoactate for 1a and 1b, respectively. Refluxing 1a/1b with excess formamide as reported [21][22][23][24] gave the cycloheptathieno [2,3-d]pyrimidin-4(3H)-one derivatives 2a/2b, respectively, which yielded the corresponding para chlorinated derivatives 3a/3b, respectively, upon treatment with phosphorus oxychloride as described in the literature [21,25]. Refluxing the appropriate sulfonamide derivative sulfaguanidine with 3a/3b in glacial acetic acid was then performed to afford the N-carbamimidoyl-4-((5,6,7,8-tetrahydrobenzo [4,5]thieno [2,3-d]pyrimidin-4-yl)amino)benzenesulfonamide/ethyl-4-((4-(N-carbamimidoylsulfamoyl) phenyl) amino)-5-methylthieno [2,3-d]pyrimidine-6-carboxylate 4ai/4bi, respectively.…”