1880
M. Tsunenaga et al. / Tetrahedron Letters 46 (2005) 1877–1880
2. Nakashima, K. Biomed. Chromatogr. 2003, 17, 83–95.
3. Matsumoto, M. J. Photochem. Photobiol. C 2004, 5, 27–
53, and references cited therein.
4. Philbrook, G. E.; Maxwell, M. A.; Taylor, R. E.; Totter, J.
R. Photochem. Photobiol. 1965, 4, 1175–1183.
O
O
O
O
Ph
Ph
Ph
Ph
C5
C6
N1
C3 C
N1
C5
4 C6
O
C3 C4
N2
N2
H O
5. Kimura, M.; Nishikawa, H.; Kura, H.; Lim, H.; White, E.
H. Chem. Lett. 1993, 505–508.
Scheme 5.
6. (a) Seliger, H. H.; McElroy, W. D. Arch. Biochem.
Biophys. 1960, 88, 136–141; (b) Schaap, A. P.; Chen,
T.-S.; Handley, R. S.; DeSilva, R.; Giri, B. P. Tetrahedron
Lett. 1987, 28, 1155–1158; (c) McCapra, F. Tetrahedron
Lett. 1993, 34, 6941.
7. (a) White, E. H.; Steinmetz, M. G.; Miano, J. D.; Wildes,
P. D.; Morland, R. J. Am. Chem. Soc. 1980, 102, 3199–
3208; (b) Beck, S.; Koster, H. Anal. Chem. 1990, 62, 2258–
2270.
8. (a) Ojima, H.; Nonoyama, K. Bull. Aichi Univ. Ed. 1992,
41(Natural Science), 17–23; (b) Nakashima, K.; Yama-
saki, H.; Kuroda, N.; Akiyama, S. Anal. Chim. Acta 1995,
303, 103–107.
9. (a) Paterson, M. J.; Robb, M. A.; Blancafort, L.; DeBellis,
A. D. J. Am. Chem. Soc. 2004, 126, 2912–2922; (b) Turro,
N. J.; McVey, J.; Ramamurthy, V.; Lechtken, P. Angew.
Chem., Int. Ed. Engl. 1979, 18, 572–586.
of amidine 9 are 39° and 41° those of monoanionic form
are 0° and 1° (Scheme 5). In the dianionic form, the di-
benzoyl amidine moiety and o-hydroxy phenyl group are
twisted each other. A naked m- or p-OÀ group cannot
avoid direct contact with solvents, which probably
would accelerate deactivation of emitters in excited
states, while an o-OÀ group of amidine 9* is somewhat
protected sterically by adjacent anionic di-benzoyl ami-
dine moieties, that is, a pocket. The twisted dibenzoyl
amidine moiety is supportive of the formation of the
pocket, in which the 2-phenyl o-hydroxy group is likely
protected from solvent contact. The electron donation
of o-OÀ may thus operate to enhance chemilumines-
cence in the pocket.
10. (a) Lophine peroxide derivatives were prepared by the
method of Kimura et al. Hu, Z. Z.; Takami, S.; Kimura,
M.; Tachi, Y.; Naruta, Y. Acta Crystallogr. C 2000,
56, e465–e466; (b) Tsunenaga, M.; Kimura, M.; Naruta,
Y. ITE Lett. Batter. New Technol. Med. 2003, 4, 633–
638.
The following statement summarizes the o-OH effect on
CL efficiency. When the reaction is triggered in an apro-
tic solvent, intrinsic electron donation of –OÀ recovers
the ortho position and enhances efficiency.
11. Probable emitters are final products, which are believed to
be the corresponding fluorescent amidine derivatives 5,
but any fluorescence related to their chemiluminescene
was not observed from resulted solutions of 4. From the
resulted solution of 4a, monobenzoylamidine 12 was
isolated quantitatively. In the chemiluminescent reaction
of lophine peroxides, confirmation of emitter is an
important work but acylated amidines are occasionally
hard to be isolated. An emitter of the case of the standard
lophine peroxide 4g also has not been known. Amidine 5g,
which was synthesized by independent method, was not
fluorescent. See Ref. 1b.
Acknowledgements
We thank the staff of the SC-NMR Laboratory of
Okayama University for measuring NMR spectra.
References and notes
1. (a) Radziszewski, B. Ber. 1877, 10, 70; (b) White, E. H.;
Harding, M. J. C. Photochem. Photobiol. 1965, 4, 1129–
1155; (c) Maeda, K.; Ojima, H.; Hayashi, T. Bull. Chem.
Soc. Jpn. 1965, 38, 76–80; (d) Kimura, M.; Morioka, M.;
Tsunenaga, M.; Hu, Z. Z. ITE Lett. Batter. New Technol.
Med. 2000, 1, 418–421; (e) Okamoto, H.; Owari, M.;
Kimura, M.; Satake, K. Tetrahedron Lett. 2001, 42, 7453–
7455; (f) Kimura, M.; Tsunenaga, M.; Koyama, T.; Iga,
H.; Aizawa, R.; Tachi, Y.; Naruta, Y. ITE Lett. Batter.
New Technol. Med. 2002, 3, 30–34.
Ph
NH
O
HN
HO
12