UNSYMMETRICALLY SUBSTITUTED PHTHALOCYANINE DERIVATIVES VIA A MODIFIED RING ENLARGEMENT REACTION OF UNSUBSTITUTED SUBPHTHALOCYANINE

Chlorosubphthalocyanine (1), obtained by an improved synthesis in a yield of 64%, was reacted with the 1,3-diiminoisoindolenines 2 or 3 of 4-tert-butylphenoxy-1,2-benzenedicarbonitrile (6) and 2,3-naphthalenedicarbonitrile (7) according to previously reported conditions of the ring enlargement reaction for the synthesis of monosubstituted phthalocyanines. As proven by DCI-MS and HPLC the product mixtures contain the expected 2-(4-tert-butylphenoxy)- and 2,3-dimethylphthalocyanines 4 and 5 as main reaction products. In addition, all other possible substituted phthalocyanines and chlorinated derivatives were found. The yields of monosubstituted phthalacyanine derivatives were improved by reacting the subphthalocyanine 1 with substituted aromatic dicarbonitriles in the presence of zinc(II) acetate. From the reaction of 1 with 6 or 6-tert-butyl-2,3-naphthalenedicarbonitrile (7) the zinc(II) chelates 4Zn and 8Zn were obtained in yields of 22 and 17% after chromatographic separation from unsubstituted and other substituted ring chelates.