A new pathway by means of transetherification during the cyclic tetramerization of 4, 5-di (alkoxyl) phthalonitrile has been developed for the synthesis of a series of novel unsymmetrical 2, 3, 9, 10, 16, 17, 23-heptakis (alkoxyl)-24-mono (dimethylaminoalkoxyl) phthalocyanines M {Pc (OR) 7 (OR′)}(M= 2H, Cu)[R= C4H9, C5H11, C8H17; R′= C2H4, CH (CH3) CH2].
[Pol, J. F. van der; Neeleman, E.; Zwikker, J. W.; Nolte, R. J. M.; Drenth, W. Recueil des Travaux Chimiques des Pays-Bas, 1988 , vol. 107, p. 615 - 620]