Multisubstituted phthalonitriles, naphthalenedicarbonitriles, and phenanthrenetetracarbonitriles as precursors for phthalocyanine syntheses

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Abstract
Electrophilic aromatic nitration under mild conditions of 4-hydroxyphthalonitrile gave 4-hydroxy-3-nitrophthalonitrile and 4-hydroxy-5-nitrophthalonitrile, while bromination yielded 3-bromo-4-hydroxyphthalonitrile, 4-bromo-5-hydroxyphthalonitrile, and 3,5-dibromo-4-hydroxyphthalonitrile. Iodination gave 4-hydroxy-5-iodophthalonitrile and 4-hydroxy-3,5-diidophthalonitrile. Coupling of 4-iodophthalonitrile, 3-iodophthalonitrile, and 5-iodo-2,3-dicyanonaphthalene with trans-1,2-bis(tri-n-butylstannyl)ethene gave trans-1,2-bis(3,4-dicyanophenyl)ethene, trans-1,2-bis(2,3-dicyanophenyl)ethene, and trans-1,2-bis(6,7-dicyanonaphthyl)ethene. Photocyclization of a dilute solution of cis- or trans-1,2-bis(3,4-dicyanophenyl)ethene in dioxane gave a 1:1 mixture of 2,3,6,7- and 2,3,5,6-tetracyanophenanthrenes separable by chromatography. Keywords: phthalonitriles, naphthalenedicarbonitriles, phenanthrenetetracarbonitriles, electrophilic substitution.