1558
A. Cors et al. / Tetrahedron Letters 49 (2008) 1555–1558
Transformations: A Guide to Functional Group Preparation, 2nd ed.;
Wiley-VCH: New York, 1999; pp 821–828.
triplet species and ion-radical transients formed by a PET
reaction of nitro arenes.
5. (a) Adams, J. P. J. Chem. Soc., Perkin Trans. 1 2002, 2586–2597; (b)
Tafesh, A. M.; Weiguny, J. Chem. Rev. 1996, 96, 2035–2052.
6. For selected examples of newly developed nitro reductions being
employed by others, see: (a) McLaughlin, M. A.; Barnes, D. M.
Tetrahedron Lett. 2006, 47, 9095–9097; (b) Jacobsen, M. F.; Moses, J.
E.; Adlington, R. M.; Baldwin, J. E. Org. Lett. 2005, 7, 641–644; (c)
Camerel, F.; Ulrich, G.; Zeissel, R. Org. Lett. 2004, 6, 4171–4174; (d)
Berque-Bestel, I.; Soulier, J. L.; Giner, M.; Rivail, L.; Langlois, M.;
Siesie, S. J. Med. Chem. 2003, 46, 2606–2620; (e) Channe Gowda, D.;
Mahesh, B.; Gowda, Sh. Indian J. Chem., Sect. B 2001, 40B, 75–77; (f)
Channe Gowda, D.; Gowda, Sh. Indian J. Chem., Sect. B 2000, 39B,
709–711.
In summary, formic acid-mediated photoreduction in
neat acetonitrile at room temperature, rapidly and mildly
reduce nitro-substituted arenes, polynuclear nitro arenes,
and nitro heteroarenes to their corresponding amines in
good to high yields. The photoreduction is initiated through
a PET process and at different excitation wavelength. This
method exhibit good functional group compatibility, show
chemoselectivity on m- and p-dinitrobenzene and can be
considered as a general and wide useful methodology.
Finally, the method is inexpensive, with simple work-up
and does not need the use of mediated-metals reduction
agents.
7. Chow, Y. L. The Chemistry of Amine, Nitroso and Nitro Compounds
and their Derivatives; Wiley: New York, 1982; Part I, Supplement F,
Chapter 6.
General method for the synthesis of substituted anilines:
The photoreactions were carried out by using a final vol-
ume of 3 mL of 0.05 M acetonitrile solutions of the nitro
arenes in the presence of 0.5 M formic acid. The solutions
were contained in rubber-stoppered quartz tubes provided
with a stir bar. These were exposed to four 15 W lamps
(Applied Photophysics) of different wavelength emissions:
254, 313, and 366 nm while a steam of dry argon saturated
with the appropriate solvent was passed in the solution
through a needle. To the photolyzed solution 1 mL of
water and an excess of solid Na2CO3 were added and
two layers were formed. The organic layer was separated,
dried with Na2SO4 and filtered-off. This organic solution
was then subjected to chromatographic analysis. The prod-
ucts formed were determined by capillary GC (HP-1 or
HP-5) on the basis of calibration curves in the presence
of cyclododecane as the internal standard after appropriate
work-up of the solution. Nitro arenes 1–11 and their
photoproducts were purchased from Aldrich Co. and Mal-
linkrodt. Compounds 13–16 were prepared according to
published procedure.31
8. (a) Frolov, A. N.; Kuznetsova, N. A.; Eltov, A. V. Russ. Chem. Rev.
1976, 45, 1024; (b) Akiyama, K.; Ikegani, Y.; Ikenoue, T.; Tero-
Kubota, S. Bull. Chem. Soc. Jpn. 1986, 59, 3269.
9. Wubbels, G. G.; Jordan, J. W.; Mills, N. S. J. Am. Chem. Soc. 1973,
95, 1281.
10. Cu, A.; Testa, A. C. J. Am. Chem. Soc. 1974, 96, 1963.
11. Letsinger, R. L.; Wubbels, G. G. J. Am. Chem. Soc. 1966, 88,
5041.
12. Hurley, R.; Testa, A. C. J. Am. Chem. Soc. 1966, 88, 4330.
13. Hurley, R.; Testa, A. C. J. Am. Chem. Soc. 1967, 89, 6917.
14. Hashimoto, S.; Sunamoto, J.; Fujii, H.; Kano, K. Bull. Chem. Soc.
Jpn. 1968, 41, 1249.
15. Hurley, R.; Testa, A. C. J. Am. Chem. Soc. 1968, 90, 1949.
16. Trotter, W.; Testa, A. C. J. Phys. Chem. 1970, 74, 845.
17. Cu, A.; Testa, A. C. J. Phys. Chem. 1973, 77, 1487.
18. Hashimoto, S.; Ueda, K.; Kano, K. Bull. Chem. Soc. Jpn. 1971, 44,
1102.
19. Cu, A.; Testa, A. C. J. Phys. Chem. 1975, 79, 644.
20. Wubbels, G. G.; Snyder, E. J.; Coughlin, E. B. J. Am. Chem. Soc.
1988, 110, 2543.
21. Fukuzumi, S.; Tokuda, Y. Bull. Chem. Soc. Jpn. 1992, 65, 831.
22. Turro, N. J. Modern Molecular Photochemistry; The Benjamin
Cummings Pushing Company: CA, 1978.
23. Murov, S. L.; Carmicheal, I.; Hug, G. L. Handbook of Photochem-
istry, 2nd ed.; Marcel Dekker: New York, 1993.
24. Nakagaki, R.; Mutai, K. Bull. Chem. Soc. Jpn. 1996, 69, 261–
274.
25. Do¨pp, D. In CRC Handbook of Organic Photochemistry and
Photobiology; Horspool, W. H., Song, P.-S., Eds.; CRC Press: Boca
Acknowledgments
The authors thank Universidad de Buenos Aires (X022),
CONICET (PIP05/5443), ANPCyT (PICT 6-12312) and
´
Raton, Florida, 1995; pp 1019–1062, Section I, Chapter 81.
26. (a) Go¨rner, H.; Do¨pp, D. J. Photochem. Photobiol., A 2003, 159, 219–
225; (b) Go¨rner, H. J. Photochem. Photobiol., A 1999, 126, 15–21.
27. Wubbles, G. G.; Letsinger, R. L. J. Am. Chem. Soc. 1974, 96, 6698–
6706.
´
Fundacion Antorchas for financial support. R.E.-B. and
S.M.B. are research members of CONICET.
28. Bunce, N. J. In CRC Handbook of Organic Photochemistry and
Photobiology; Horspool, W. H., Song, P.-S., Eds.; CRC Press: Boca
References and notes
´
Raton, Florida, 1995; pp 1181–1192, Section I, Chapter 86.
1. Ono, N. The Nitro Group in Organic Synthesis; Wiley-VCH: New
York, 2001.
29. (a) Mahdavi, F.; Bruton, T. C.; Li, Y. J. Org. Chem. 1993, 58, 744–
746; (b) Chapman, O. L.; Heckert, D. C.; Reasoner, W.; Thackaberry,
S. P. J. Am. Chem. Soc. 1966, 88, 5550.
30. (a) Go¨rner, H.; Do¨pp, D. J. Chem. Soc., Perkin Trans. 2 2002, 120–
125; (b) Frolov, A. N.; Kuznetsova, N. A.; Eltsov, A. V.; Rtishcher, I.
Zh. Org. Khim. 1973, 9, 963–973.
2. Olah, G. A.; Malhotra, R.; Narane, S. C. In Nitration: Methods and
Mechanisms; Fever, H., Ed.; Wiley-VCH: New York, 1989.
3. Ehernkanfer, R.; Ram, S. Tetrahedron Lett. 1984, 25, 3415.
4. (a) Kabalka, G. W.; Varma, R. S. In Comprehensive Organic
Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon: Oxford, UK,
1991; Vol. 8, pp 363–379; (b) Larock, R. C. Comprehensive Organic
31. Bonesi, S. M.; Ponce, M. A.; Erra-Basells, R. J. Heterocycl. Chem.
2004, 41, 161–171.