A. Weitemeyer et al., UNSYMMETRICALLY SUBSTITUTED PHTHALOCYANINE DERIVATIVES VIA A MODIFIEDRING ENLARGEMENT REACTION OF UNSUBSTITUTED SUBPHTHALOCYANINE, Journal of organic chemistry, 60(15), 1995, pp. 4900-4904
Chlorosubphthalocyanine (1), obtained by an improved synthesis in a yi
eld of 64%, was reacted with the 1,3-diiminoisoindolenines 2 or 3 of 4
-tert-butylphenoxy-1,2-benzenedicarbonitrile (6) and 2,3-naphthalenedi
carbonitrile (7) according to previously reported conditions of the ri
ng enlargement reaction for the synthesis of monosubstituted phthalocy
anines. As proven by DCI-MS and HPLC the product mixtures contain the
expected 2-(4-tert-butylphenoxy)- and 2,3-dimethylphthalocyanines 4 an
d 5 as main reaction products. In addition, all other possible substit
uted phthalocyanines and chlorinated derivatives were found. The yield
s of monosubstituted phthalacyanine derivatives were improved by react
ing 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 4
Zn and 8Zn were obtained in yields of 22 and 17% after chromatographic
separation from unsubstituted and other substituted ring chelates.