Synthesis of novel 2,3-condensed thieno[2,3- d ]pyrimidin-4-ones via Appel's salt chemistry

The chemistry of imino-1,2,3-dithiazoles possessing a thiophene ring with various alkyl and aromatic diamines was investigated in the expectation of obtaining novel 2,3-condensed thieno2,3-d]pyrimidinone derivatives. Obtained via Appel's salt's (1) chemistry, methyl N-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)-2-thiophenecarboxylate (2) is confirmed as a very interesting starting material for access to a variety of novel thiophene bioisosters of bioactive pentacyclic tetraaza-pentaphene-5, 8-diones.