LETTER
A. B. P., Eds.; VCH: Weinheim, 1993. (f)Phthalocyanines:
Novel Synthesis of Metal-Free Phthalocyanines
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(9) (a) Brach, P. J.; Grammatica, S. J.; Ossanna, O. A.;
Properties and Applications, Vol. 4; Leznoff, C. C.; Lever,
A. B. P., Eds.; VCH: Weinheim, 1996. (g) Thomas, A. L.
The Phthalocyanines: Reserch and Applications; CRC
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(11) The results will be published in J. Org. Chem.
(12) Byrne, G. T.; Linstead, R. P.; Lowe, A. R. J. Chem. Soc.
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(13) Typical Procedure for the Preparation of 3a. A glass tube
was charged with phthalimide (100 mg, 0.68 mmol), p-
TsOH·H2O (13 mg, 0.07 mmol), HMDS (560 mL, 438 mg,
2.7 mmol) and DMF (50 mL, 0.68 mmol) under argon
atmosphere. Then the tube was sealed. The mixture was
heated at 150 °C, when a dark purple solid immediately
appeared. After heating for 10 h, the mixture was cooled and
filtered. The solid was washed with MeOH, and then
dissolved in conc. H2SO4 (5.0 mL). The resulting solution
was poured into H2O (100 mL) and the blue precipitates
were filtered and washed with H2O. The solid was further
purified by extraction by soxhlet extractor with methanol to
give 62 mg (58%) of 3a as a blue solid.
(14) Metal-free phthalocyanines are not formed in the absence of
either p-TsOH or DMF. p-TsOH probably plays a role to
activate HMDS as a silylating agent as well as phthalimides
and DMF is requisite for dissolving substrates, although the
role of these reagents is not clear enough.
(15) Barrett, P. A.; Bradbrook, E. F.; Dent, C. E.; Linstead, R. P.
J. Chem. Soc. 1939, 1820.
(16) Mikhalenko, S. A.; Barkanova, S. V.; Lebedev, O. L.;
Luk’yanets, E. A. Zh. Obshch. Khim. 1971, 41, 2735.
(17) Mikhalenko, S. A.; Luk’yanets, E. A. Zh. Obshch. Khim.
1969, 39, 2554.
(2) Linstead, R. P. J. Chem. Soc. 1934, 1016.
(3) (a) Wyler, M. US. Pat. Appl. 2197458, 1940; Chem. Abstr.
1940, 34, 37564. (b) Wyler, M. US. Pat. Appl. 2197459,
1940; Chem. Abstr. 1940, 34, 37564.
(4) For example: (a) Sander, A. Die Chemie 1942, 55, 255.
(b) Borodkin, V. F. J. Appl. Chem. USSR (Engl. Transl.)
1958, 31, 803; Zh. Priklad. Khim. 1958, 31, 813.
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Lett. 1980, 1277. (b) Tomoda, H.; Saito, S.; Shiraishi, S.
Chem. Lett. 1983, 313. (c) Wöhrle, D.; Schnurpfeil, G.;
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Chem. 1989, 26, 1887.
(7) (a) Lee, C.-H.; Ng, D. K. P. Tetrahedron Lett. 2002, 43,
4211. (b) Under similar conditions, Ce-phthalocyanine has
been reported to be produced in good yield, see: Tomilova,
L. G.; Chernykh, E. V.; Nikolaeva, T. B.; Zelentsov, V. V.;
Luk’yanets, E. A. J. Gen. Chem. USSR (Engl. Transl.) 1984,
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(18) We also found that metal-free phthalocyanines were
obtainable from phthalonitriles by the action of HMDS. The
results will be reported in due course.
(8) Timokhin, G. A.; Kissin, B. I.; Faeshkina, N. N. Appl. Chem.
USSR 1969, 42, 2187.
Synlett 2003, No. 13, 2083–2085 © Thieme Stuttgart · New York