1,8‐Dihydrodithieno[3,4‐ b :3′,4′‐ i ]‐1,4,8,11‐tetraaza[14]annulene 4 H ,12 H ‐[1,4,8,11]Tetraazacyclotetradecino[2,3‐ c :9,10‐ c ]‐dithiophene)

1,8‐Dihydrodithieno[3,4‐ b :3′,4′‐ i ]‐1,4,8,11‐tetraaza[14]annulenes (4 H ,12 H ‐[1,4,8,11]Tetraazacyclotetradecino[2,3‐ c :9,10‐ c′ ]dithiophenes) The title compounds 3a–h , disubstituted in 6,13 positions by alkyl‐, 3‐hydroxypropyl‐, and ethoxycarbonyl groups, are prepared by cyclocondensation of 3,4‐diaminothiophene ( 1 ) with 2‐alkyl‐3‐ethoxyacroleins ( 2a–f ), 3, 4‐dihydro‐2 H ‐pyran‐5‐carbaldehyde ( 2g ), and 2‐(ethoxy‐carbonyl)‐3‐hydroxyacrolein ( 2h ), respectively. Metal template cyclocondensations of the starting materials 1 and 2a–h in the presence of nickel(II) acetate affords the nickel(II) chelates ( 4a–h ) of the macrocyclic N 4 ligands 3 .