3536 Bull. Korean Chem. Soc. 2012, Vol. 33, No. 11
Communications to the Editor
H. Synlett 2010, 379.
acyclic α,β-unsaturated ketone substrates in the presence of
this solvent free system at room temperature for 18 h. These
results are shown in Table 1. Substrates 1b,8 1c,9 1e10 and
1g11 were prepared by known procedure. The reaction of 1b,
1f, and 1h with cyclic enone gave 3ba, 3fa, and 3ha in
higher yield (entries 2, 6, and 9). The reaction of 1a, 1d, 1e,
and 1g with cyclic enone provided the corresponding N-
heterocycles in moderate yields (entries 1, 4, 5, and 7). For
imidazole 1c and purine 1l, yields were low (entry 3 and 10).
In the case of entry 8, CeCl3·7H2O-NaI-SiO2 system
catalyzed Michael reaction of 1,2,3-triazole with 1-acetyl 1-
cyclopentene provided an isomeric mixture of trans (51%)
and cis triazole (17%). The stereochemistry of those isomers
was identified according to the previous paper,7b in which
we described that 1,3-dipolar one pot reaction of organic
azides and phenylacetylene with acetyl cyclopentene yields
1,2,3-triazoles, same as aza-Michael reaction products. And
the identification of the triazoles was performed on the
previous basis of documentation by X-ray crystallography.
In conclusion, we have found that solvent free CeCl3·7H2O-
NaI-SiO2 system efficiently catalyzed aza-Michael addition
of pyrazoles, imidazole, triazoles and purine with α,β-un-
saturated ketone in moderate yields by a one-pot procedure.
3. Reimlinger, H.; Oth, J. F. M. Chem. Ber. 1964, 97, 331.
4. (a) Ferroni, R.; Milani, L.; Simoni, D.; Orlandini, P.; Guarneri, M.;
Franze, D.; Bardi, A. IL Farmaco. 1989, 44, 495. (b) Weintraub,
P. M.; Tiernan, P. L.; Huffman, J. C. J. Heterocycl. Chem. 1987,
24, 561. (c) Srivastava, N.; Banik, B. K. J. Org. Chem. 2003, 68,
2109. (d) Bartoli, G.; Bartolacci, M.; Giuliani, A.; Marcantoni, E.;
Massaccesi, M.; Torregiani, E. J. Org. Chem. 2005, 70, 169. (e)
Firouzabadi, H.; Iranpoor, N.; Jafari, A. A. Adv. Synth. Catal.
2005, 347, 655. (f) Reddy, K. R.; Kumar, N. S. Synlett 2006, 2246.
(g) Aburatani, S.; Kawatsura, M.; Uenishi, J. Heterocycles 2007,
71, 189. (h) Liu, B. K.; Wu, Q.; Qian, X. Q.; Lv, D. S.; Lin, X. F.
Synthesis 2007, 17, 2653.
5. (a) Uddin, M. I.; Nakano, K.; Ichikawa, Y.; Kotsuki, H. Synlett
2008, 1402. (b) Zhou, Y.; Li, X.; Li, W.; Wu, C.; Liang, X.; Ye, J.
Synlett 2010, 2357. (c) Xu, W. F.; Chen, Q.; Liu, R. Q.; Ren, F. B.;
Zhou, Y. F.; Lu, X. L. Asian J. Chem. 2011, 23, 4165.
6. (a) Bartoli, G.; Bosco, M.; Marcantoni, E.; Petrini, M.; Sambri, L.;
Torregiani, E. J. Org. Chem. 2001, 66, 9052. (b) Bartoli, G.;
Bartolacci, M.; Bosco, M.; Foglia, G.; Giuliani, A.; Marcantori,
E.; Sambri, L.; Torregiani, E. J. Org. Chem. 2003, 4594.
7. (a) Choi, I. Y.; Lim, H. J.; Lee, G. C.; Park, U. G.; Kong, J. Y.
KR20090090457 A. (b) Lee, I. Y. C.; Yu, O. J.; Lim, H.-J.; Lee, H.
W. Bull. Korean Chem. Soc. 2008, 29, 723.
8. García, M. A.; López, C.; Claramunt, R. M.; Kenz, A.; Pierrot, M.;
Elguero, J. Hel. Chim. Acta 2002, 85, 2763.
9. Bellina, F.; Cauteruccio, S.; Rossi, R. J. Org. Chem. 2007, 72,
8543.
10. (a) Xu, L.; Zhang, S.; Trudell, M. L. Chem. Commun. 2004, 1668.
(b) Atkinson, M. R.; Polya, J. B. J. Chem. Soc. 1954, 3319.
11. Jin, T.; Kamijo, S.; Yamamoto, Y. Eur. J. Org. Chem. 2004, 3789.
12. Typical procedure: To a mixture of CeCl3·7H2O (100 mg, 0.27
mmol) and NaI (41 mg, 0.27 mmol) in CH3CN (6 mL) was added
SiO2 (414 mg, 70-230 mesh, Merck). The mixture was stirred for
overnight at room temperature and the solvent was removed in
vacuo. The freshly prepared resulting mixture was added to
pyrazole (100 mg, 0.694 mmol) and 2-cyclopentene-1-one (87
μL, 1.04 mmol). After being stirred for overnight, CH2Cl2 was
added and this suspension was passed through a short pad of
Celite. The filtrate was concentrated under reduced pressure to
give crude product which was purified by flash column chromato-
graphy (SiO2, hexane: ethyl acetate = 2:1) to provide pure
product. 3aa: 1H NMR (300 MHz, CDCl3) δ 7.78 (s, 1H), 7.53 (s,
1H), 7.44 (d, J = 2.1 Hz, 1H), 6.26 (t, J = 2.0 Hz, 1H), 4.95 (pent,
J = 6.4 Hz, 1H), 2.83 (dd, J = 18.4, 6.6 Hz, 1H), 2.94 (dd, J = 18.6,
7.6 Hz, 1H), 2.65-2.25 (m, 4H); 13C NMR (75 MHz, CDCl3) δ
215.2, 139.8, 128.0, 105.7, 58.7, 44.9, 36.9, 30.4. MS (m/z, relative
int): 150 (M+, 17), 122 (63), 94 (100), 68 (67), 54 (92), 52 (50).
Acknowledgments. This work was supported by the
research grant of the Chungbuk National University in 2010.
References
1. β-Amino carbonyl compound: (a) Perlmutter, P. Conjugate Addition
Reactions in Organic Synthesis; Pergamon: New York, 1992; p
114. (b) Liu, M.; Sibi, M. P. Tetrahedron 2002, 58, 7991. (b) Xu,
L.-W.; Xia, C.-G. Eur. J. Org. Chem. 2005, 633. (d) Krishna, P. R.;
Sreeshailam, A.; Srinivas, R. Tetrahedron 2009, 65, 9657.
2. (a) Matsubara, S.; Yoshioka, M.; Utimoto, K. Chem. Lett. 1994,
23, 827. (b) Loh, T.-P.; Wei, L.-L. Synlett 1998, 975. (c) Wabnitz,
T. C.; Spencer, J. B. Tetrahedron Lett. 2002, 43, 3891. (d) Varala,
R.; Alam, M. M.; Adapa, S. R. Synlett 2003, 720. (e) Xu, L.-W.;
Li, L.; Xia, C.-G. Hel. Chim. Acta 2004, 87, 1522. (f) Reboule, I.;
Gil, R.; Collin, J. Tetrahedron Lett. 2005, 46, 7761. (g) Duan, Z.;
Xuan, X.; Li, T.; Yang, C.; Wu, Y. Tetrahedron Lett. 2006, 5433.
(h) Azizi, N.; Baghi, R.; Ghafuri, H.; Bolourtchian, M.; Mohammad,