Synthesis of new heteroaromatic nitrogen ligands: Pyrimido‐[4″,5″:4′,5′]‐thieno[3′,2′:4,5]thieno[3,2‐d]pyrimidines and 1,2,3‐triazine[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2‐d]‐1,2,3‐triazines

An efficient one‐pot access for the synthesis of the previously unreported tetracyclic fused pyrimido‐4″,5″:4′,5′]thieno3′,2′:4,5]thieno3,2‐d]pyrimidine ( 3 ) and 1,2,3‐triazine4″,5″:4′,5′]thieno‐3′,2′:4,5]thieno‐3,2‐d]‐1,2,3‐triazine ( 5 ) heteroaromatic nitrogen ligands is described. The title compounds 3 and 5 were obtained from 3,4‐diaminothieno2,3‐b]thiophene‐2,5‐dicarbonitrile and phosgeniminium chloride and sodium nitrite/HCl, respectively. Substituted condensed thieno2,3‐b]thiophene derivatives 4 and 6 were synthesized by nucleophilic displacement of the chloroderivatives 3 and 5 .