Eh. Morkved et al., PREPARATIONS AND TEMPLATE CYCLOTETRAMERISATIONS OF 2,1,3-BENZOTHIA(SELENA)DIAZOLE-5,6-DICARBONITRILES, Acta chemica Scandinavica, 49(9), 1995, pp. 658-662
2,1,3-Benzothiadiazole-5,6-dicarbonitril Ib, and the corresponding sel
ena derivative 2b, have been prepared in multistep syntheses. Template
cyclotetramerisations with copper or magnesium powder in an inert atm
osphere give the thiadiazole substituted phthalocyanines 4 in good yie
lds and the selenadiazole analogues 5a and 5b + 5c (3:7 mixture) in fa
ir yields. Compounds 5 are the first examples of phthalocyanines with
a selenium-containing substituent.