K. C. Majumdar, S. Mondal / Tetrahedron Letters 48 (2007) 6951–6953
6953
7. Peter, A. N.; Thomas, B.; Anna, K.; Tero, L.; Peter, S.
Substituted Pyrrolopyridines. WO 2004016609, 2004;
Chem. Abstr. 2004, 140, 217627.
8. Cacchi, S.; Fabrizi, G.; Parisi, L. M.; Bernini, R. Synlett
2004, 287.
9. (a) Majumdar, K. C.; Rahaman, H.; Islam, R.; Roy, B.
Tetrahedron Lett. 2006, 47, 2111; (b) Majumdar, K. C.;
Muhuri, S. Synthesis 2006, 2725; (c) Majumdar, K. C.;
Alam, S. Org. Lett. 2006, 8, 4059.
available, inexpensive 3-amino- or 2-aminopyridine as
starting materials, (2) regioselective cross coupling of
the alkyne group, and (3) mild base induced cyclization.
In comparison, Cacchi et al. used K2CO3 in 1,4-dioxane
at 110 °C for 24 h with 2,2,2-trifluoro-N-(3-(2-phenyl-
ethnyl)quinoxalin-2-yl)acetamide to obtain only a 22%
yield of the cyclized product.8
10. Compound 4a, (6-bromo-2-(2-phenylethynyl)pyridine-3-
amine): White solid, mp 120–122 °C, yield 75%. IR
Acknowledgements
(KBr, cmÀ1
) mmax:
3455, 3312; 1H NMR (CDCl3,
400 MHz) d: 6.94 (d, 1H, ArH, J = 8.6 Hz), 7.20 (d, 1H,
ArH, J = 8.5 Hz), 7.33–7.37 (m, 3H, ArH), 7.56–7.58 (m,
2H, ArH); 13C NMR (CDCl3, 100 MHz) d: 84.3, 96.4,
122.1, 124.2, 128.3, 128.7, 129.4, 132, 144.1; MS (m/z): 272
(M+) 274. Anal. Calcd for C13H9BrN2: C, 57.17; H, 3.32;
N, 10.26. Found: C, 57.03; H, 3.33; N, 10.39.
We thank the CSIR (New Delhi) for financial assistance.
We also thank the DST (New Delhi) for providing UV–
vis and IR spectrometers under the DST-FIST program.
References and notes
11. Nakamura, H.; Aizawa, M.; Takeuchi, D.; Murai, A.;
Shimoura, O. Tetrahedron Lett. 2004, 41, 2185.
12. Jiang, B.; Yang, C. G.; Xiong, W. N.; Wang, J. Bioorg.
Med. Chem. 2001, 9, 1149.
13. Sonogashira, K.. In Comprehensive Organic Synthesis;
Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford,
1991; Vol. 3,, Chapter 2.3, p. 521.
14. Lu, B. Z.; Zhao, W.; Wei, H. X.; Dufour, M.; Farina, V.;
Senanayake, C. H. Org. Lett. 2006, 8, 3271.
1. (a) Mitzutani, M.; Sanemitsu, Y.; Tamaru, Y.; Yoshida,
Z. Tetrahedron Lett. 1985, 26, 1237; (b) Mitzutani, M.;
Sanemitsu, Y. Tetrahedron 1986, 42, 305.
2. (a) Utimoto, K.; Miwa, H.; Nazaki, H. Tetrahedron Lett.
1981, 22, 4277; (b) Trost, B. M.; Keinan, E. J. Org. Chem.
1980, 45, 2741; (c) Murahashi, S.; Shimamura, T.;
Moritani, I. J. Chem. Soc., Chem. Commun. 1974, 931.
3. (a) Rudisill, D. E.; Stille, J. K. J. Org. Chem. 1989, 54,
5856; (b) Ciattini, P. G.; Morera, E.; Ortar, G. Tetrahe-
dron Lett. 1994, 35, 2405; (c) Larock, R. C.; Yum, E. K. J.
Am. Chem. Soc. 1991, 113, 6689; (d) Larock, R. C.; Yum,
E. K.; Refvik, M. D. J. Org. Chem. 1998, 63, 7652.
4. (a) Ujjainwalla, F.; Warner, D. Tetrahedron Lett. 1998, 39,
5355; (b) Hopkins, C. R.; Collar, N. Tetrahedron Lett.
2004, 45, 8087; (c) McLaughlin, M.; Palucki, M.; Davies,
I. W. Org. Lett. 2006, 8, 3307.
5. (a) Kuethe, J. T.; Wong, A.; Qu, C.; Smitrovich, J.;
Davies, I. W.; Hughes, D. L. J. Org. Chem. 2005, 70, 2555;
(b) Van Zandt, M. C.; Jones, M. L.; Gunn, D. E.; Geraci,
L. S.; Jones, J. H.; Sawicki, D. R.; Sredy, J.; Jacot, J. L.;
Dicioccio, A. T.; Petrova, T.; Mitschler, A.; Podjarny, A.
D. J. Med. Chem. 2005, 48, 3141; (c) Faulkner, D. J. Nat.
Prod. Rep. 1999, 16, 155; (d) Lounasmaa, M.; Tolvanen,
A. Nat. Prod. Rep. 2000, 17, 175.
15. Compound 6a, (5-bromo-2-phenyl-1H-pyrrol[3,2-b]pyri-
dine): White solid, mp above 245 °C, yield 71%. IR
1
(KBr, cmÀ1) mmax: 3135; H NMR (DMSO-d6, 400 MHz)
d: 7.05 (d, 1H, CH@C, J = 1.4 Hz), 7.23 (d, 1H, ArH,
J = 8.4 Hz), 7.40 (t, 1H, ArH, J = 7.3 Hz), 7.51 (t, 2H,
ArH, J = 7.5 Hz), 7.72 (d, 1H, ArH, J = 8.4 Hz), 7.92 ( d,
2H, ArH, J = 7.5 Hz), 12.04 (s, 1H, NH); 13C NMR
(CDCl3, 100 MHz) d: 98.8, 119.5, 120.8, 125.7, 128.4,
128.8, 129.1, 131.4, 133.8, 142.5, 147.5; HRMS
(C13H9BrN2) Calcd: 273.0027 (M+H (79Br)), 275.0007
(M+H (81Br)). Found: 273.0022 (M+H (79Br)) (M+H
(81Br)). Anal. Calcd for C13H9BrN2: C, 57.17; H, 3.32; N,
10.26. Found; C, 57.33; H, 3.18; N, 10.22.
16. General procedure for the synthesis of compounds 6a,b and
11a,b: Triethylamine (0.18 mL, 50 mol %) was added to a
solution of compound 5a (1 g, 2.70 mmol) in dry DMF
(10 mL) and the reaction was heated for 1 h at 100 °C.
After cooling the reaction mixture, water (30 mL) was
added and stirring continued for 3 h. The resulting solid
precipitate was filtered and dried over CaCl2, to afford 6a
(0.517 g, 71%) as a white solid. Similarly, the other
substrates 5b and 10a,b were subjected to the same
reaction conditions to give products 6b and 11a,b.
6. (a) Henry, J. R.; Rupert, K. C.; Dodd, J. H.; Turchi, I. J.;
Wadsworth, S. A.; Cavender, D. E.; Fahmy, B.; Olini, G.
C.; Davis, J. E.; Pellegrino-Gensey, J. L.; Schafer, P. H.;
Siekierka, J. J. J. Med. Chem. 1998, 41, 4196; (b) Henry, J.
R.; Rupert, K. C.; Dodd, J. H.; Turchi, I. J.; Wadsworth,
S. A.; Cavender, D. E.; Schafer, P. H.; Siekierka, J. J.
Bioorg. Med. Chem. Lett. 1998, 8, 3335.