Cobalt(II) Chloride as a Novel and Efficient Catalyst for the Synthesis of 1,2,5-Trisubstituted Pyrroles 595
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R.; Marshal, G. R.; Di Santo, R.; Costi, R.; Rompei,
S.; Artico, M. Bioorg Med Chem 2000, 8, 1423–
1432.
C10H17N: C, 76.41; H, 11.33; N, 9.26. Found: C, 76.43;
H, 11.38; N, 9.30.
2-(2,5-Dimethyl-1H-pyrrol-1yl)-pyridine (2g, en-
1
try 7): H NMR (300 MHz, CDC13) δ: 2.10 (s, 6H),
5.92 (s, 2H), 7.27 (m, 2H), 7.81 (m, 1H), 8.61 (m,
1H); HRMS Calcd for C11H12N2 172.1000, found
172.1002. Anal Calcd for C11H12N: C, 76.71; H, 7.02;
N, 16.27. Found: C, 76.76; H, 7.05, N, 16.30.
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2, 554–565.
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7752.
2,5-Dimethy-1-(naphthalene-1-yl)-1H-pyrrole (2i,
entry 9): mp 120–121◦C; 1H NMR (300 MHz, CDC13)
δ: 1.91 (s, 6H), 6.01 (s, 2H), 7.15 (d, J = 8.2 Hz, 1 H),
7.36–7.59 (m, 4H), 7.94 (d, J = 8.2 Hz, 2H); HRMS
Calcd for C16H15N 221.1204, found 221.1206. Anal
Calcd for C16H15N: C, 86.84; H, 6.83; N, 6.33. Found:
C, 86.88; H, 6.85; N, 6.31.
[4] Gilchrist, T. L. J Chem Soc, Perkin Trans 1 1998,
615–628.
[5] (a) Hantzsch, A. Ber Dtsch Chem Ges 1890, 23, 1474;
(b) Trautwein, A. W.; Submuth, R. D.; Jung, G. Bioorg
Med Chem Lett 1998, 8, 2381.
[6] (a) Knorr, L. Ber Dtsch Chem Ges 1884, 17, 1635;
(b) Alberola, A.; Ortega, A. G.; Sadaba, M. L.; Sanudo,
C. Tetrahedron 1999, 55, 6555–6566.
[7] Katritzky, A. R.; Jiang, J.; Steel, P. J. J Org Chem
1994, 59, 4551–4556.
[8] (a) Paal, C. Ber Dtsch Chem Ges 1885, 18, 367;
(b) Jones, R. A.; Been, R. G. P. The Chemistry of
Pyrroles; Academic Press: New York, 1977, p. 3;
(c) Chiu, P. K.; Sammes, M. P. Tetrahedron 1990,
46, 3439–3456.
[9] Yu, S. X.; Quesne, P. W. Tetrahedron Lett 1995, 36,
6205–6208.
1-(Anthracen-1-yl)-2,5-dimethyl-1H-pyrrole (2j,
entry 10): mp 183–184◦C; 1H NMR (300 MHz,
CDC13) δ: 1.95 (s, 6H), 6.04 (s, 2H), 7.35–7.59 (m,
4H), 7.71 (s, 1H), 7.92 (d, J = 8 Hz, 1H), 8.02 (d,
J = 7.9 Hz, 1H), 8.10 (d, J = 8.4 Hz, 1H), 8.52 (s,
1H); HRMS Calcd for C20H17N 271.1361, found
271.1362. Anal Calcd for C20H17N: C, 88.52; H, 6.31;
N, 5.16. Found: C, 88.58; H, 6.37; N, 5.20.
[10] Ballini, R.; Barboni.; Bosica, G.; Petrini, M. Synlett
2000, 391–393.
1
2-Methyl-1,5-dipheny-1H-pyrrole (Scheme 2): H
NMR (300 MHz, CDC13) δ: 2.15 (s, 3H), 6.09 (d,
J = 3.6 Hz, 1H), 6.32 (d, J = 3.5 Hz, 1H), 7.02–7.40
(m, 10H); HRMS Calcd for C17H15N 233.1204, found
233.1206. Anal Calcd for C17H17N: C, 87.52; H, 6.48;
N, 6.00. Found: C, 87.58; H, 6.54; N, 6.04.
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heron Lett 2005, 46, 2643–2645.
[12] Yadav, J. S.; Reddy, B. V.; Eeshwaraiah, B.; Gupta,
M. K. Tetraheron Lett 2004, 45, 5873.
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[14] Banik, B. K.; Samajdar, S.; Banik, I. J Org Chem 2004,
69, 213–216.
CONCLUSION
[15] (a) Wang, B.; Gu, Y.; Luo, C.; Yang, T.; Yang, L.;
Suo, J. Tetrahedron Lett 2004, 45, 3417; (b) Curini,
M.; Montanari, F.; Rosati, O.; Lioy, E.; Margarita,
R. Tetrahedron Lett 2003, 44, 3923; (c) Ullrich, T.;
Ghobrial, M.; Weigand, K. Synth Commun 2007, 37,
1109.
[16] (a) Lumby, R. J. R.; Joensuu, P. M.; Lam, H. M.
Org Lett 2007, 9, 4367; (b) Velusamy, S.; Borpuzari,
S.; Punniyamurthy, T. 2005 Tetrahedron 61, 2011;
(c) De, S. K. Tetrahedron Lett 2004, 45, 1035.
[17] (a) De, S. K.; Gibbs, R. Tetrahedron Lett 2004, 45,
7404–7407; (b) De, S. K.; Gibbs, R. A. Tetrahedron
Lett 2005, 45, 1647–1649; (c) De, S. K.; Gibbs, R. A.
Tetrahedron Lett 2005, 46, 1811–1813; (d) Royer, L.;
De, S. K.; Gibbs, R. A. Tetrahedron Lett 2005, 46,
4595–4597.
In summary, a very simple and convenient method
has been developed for the synthesis of N-
substituted pyrroles under solvent-free conditions.
The method has advantages in terms of yields, short
reaction times, ease of operation, and cheap catalyst,
and will make a useful and important addition to the
present methodologies.
REFERENCES
[1] (a) Sundberg, R. A.; In Comprehensive Heterocyclic
Chemistry; Katritzky, A.; W. Rees, C. W. (Eds.),
Heteroatom Chemistry DOI 10.1002/hc