ꢀ
L. Racane et al. / Tetrahedron 67 (2011) 2760e2767
2767
colorless crystals, mp 267e269 ꢀC. IR (ATR):
2899, 2848, 1614, 1521, 1427, 1338, 1213, 1178, 786, 647, 596 cmꢁ1
1H NMR (600 MHz, DMSO-d6):
¼2.88 (s, 6H, HeCH3), 7.78 (d, 2H,
J¼8.4 Hz, HeAr), 8.25 (d, 2H, J¼8.4 Hz, HeAr), 12.46 (s, 1H, HeNH).
13C NMR (151 MHz, DMSO-d6):
(d), 119.3 (s), 133.1 (s), 152.2 (s), 164.5 (s). LCeMS (ESI): m/z¼310.1
(MHþ). Anal. Calcd for C16H11N3S2 (309.41): C, 62.11; H, 3.58; N,
13.58. Found: C, 62.22; H, 3.46; N, 13.71.
y
¼3115, 3074, 3026,
References and notes
.
1. (a) Gunawardana, G. P.; Kohomoto, S.; Gunasekera, S. P.; McConnell, O. J.;
Koehn, F. E. J. Am. Chem. Soc. 1988, 110, 4856e4858; (b) Gunawardana, G. P.;
Kohomoto, S.; Burres, N. S. Tetrahedron Lett. 1989, 30, 4359e4362.
2. Rajashekar, H.; Ramesh, D.; Chandrashekhar, C.; Mahadevan, K. M.; Vaidya, V. P.
Indian J. Heterocycl. Chem. 2009, 18, 205e210.
3. Tapia, R. A.; Prieto, Y.; Pautet, F.; Walchshofer, N.; Fillion, H.; Fenet, B.; Sarciron,
M.-E. Bioorg. Med. Chem. 2003, 11, 3407e3412.
4. Tapia, R. A.; Prieto, Y.; Pautet, F.; Domard, M.; Sarciron, M.-E.; Walchshofer, N.;
Fillion, H. Eur. J. Org. Chem. 2002, 4005e4010.
d
d
¼19.7 (q), 114.1 (d), 117.9 (s), 118.3
5. Janosik, T.; Wahlstrom, N.; Bergman, J. Tetrahedron 2008, 64, 9159e9180.
6. Asche, C.; Demeunynck, M. Anti-Cancer Agents Med. Chem. 2007, 7, 247e267.
7. Tsuchimoto, T.; Matsubayashi, H.; Kaneko, M.; Nagase, Y.; Miyamura, T.;
Shirakawy, E. J. Am. Chem. Soc. 2008, 130, 15823e15835.
8. Yu, Y.; Singh, S. K.; Liu, A.; Li, T.-K.; Liu, L. F.; LaVoie, E. J. Bioorg. Med. Chem.
2003, 11, 1475e1491.
4.11.3. 6H-Dithiazolo[4,5-c:50,40-g]carbazole 14a. Crystallization from
DMF/H2O gave 0.184 g (65.4%) of colorless crystals, mp>300 ꢀC. IR
(ATR):
694 cmꢁ1
J¼8.8 Hz, HeAr), 8.17 (d, 2H, J¼8.8 Hz, HeAr), 9.29 (s, 2H, H-2, H-10),
y
¼3184, 3116, 3022, 1587, 1458, 1390, 1306, 1227, 876, 785,
.
1H NMR (300 MHz, DMSO-d6, 80 ꢀC):
d
¼7.82 (d, 2H,
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
9. (a) Racane, L.; Tralic-Kulenovic, V.; Kraljevic Pavelic, S.; Ratkaj, I.; Peixoto, P.;
13
ꢀ
12.07 (s, 1H, HeNH). C NMR (75 MHz, DMSO-d6, 80 ꢀC):
¼150.9
d
Nhili, R.; Depauw, S.; Hildebrand, M.-P.; David-Cordonnier, M.-H.; Pavelic, K.;
Karminski-Zamola, G. J. Med. Chem. 2010, 53, 2418e2432; (b) Racane, L.; Kralj,
M.; Suman, L.; Stojkovic, R.; Tralic-Kulenovic, V.; Karminski-Zamola, G. Bioorg.
Med. Chem. 2010, 18, 1038e1044.
ꢀ
(d), 148.9 (s), 137.9 (s), 126.4 (s), 121.2 (d), 114.8 (s), 111.9 (d). LCeMS
(ESI): m/z¼282.0 (MHþ). Anal. Calcd for C14H7N3S2 (281.36): C, 59.76;
H, 2.51; N, 14.93. Found: C, 59.93; H, 2.48; N, 14.77.
ꢁ
ꢀ
ꢀ
ꢀ
ꢁ
ꢁ
ꢀ
10. (a) Dogan Koruznjak, J.; Grdisa, M.; Slade, N.; Zamola, B.; Pavelic, K.;
Karminski-Zamola, G. J. Med. Chem. 2003, 46, 4516e4524; (b) Jarak, I.;
ꢁ
ꢁ
ꢀ
ꢀ
Kralj, M.; Suman, L.; Pavlovic, G.; Dogan, J.; Piantanida, I.; Zinic, M.;
4.11.4. 2,10-Dimethyl-6H-dithiazolo[4,5-c:50,40-g]carbazole
ꢀ
Pavelic, K.; Karminski-Zamola, G. J. Med. Chem. 2005, 48, 2346e2360.
11. Ester, K.; Hranjec, M.; Piantanida, I.; Caleta, I.; Jarak, I.; Pavelic, K.; Kralj, M.;
ꢀ
ꢀ
14b. Crystallization from DMF/H2O gave 0.234 g (75.7%) of color-
Karminski-Zamola, G. J. Med. Chem. 2009, 52, 2482e2492.
12. Hranjec, M.; Kralj, M.; Piantanida, I.; Sedic, M.; Suman, L.; Pavelic, K.; Kar-
less crystals, mp>300 ꢀC. IR (ATR):
y
¼3188, 3138, 3037, 2937, 1618,
ꢁ
ꢀ
ꢀ
1585, 1520, 1425, 1402, 1308, 1176, 874, 800, 617 cmꢁ1 1H NMR
.
minski-Zamola, G. J. Med. Chem. 2007, 50, 5696e5711.
ꢁ
ꢀ
13. Hranjec, M.; Piantanida, I.; Kralj, M.; Suman, L.; Pavelic, K.; Karminski-Zamola,
(300 MHz, DMSO-d6):
d
¼2.88 (s, 6H, HeCH3), 7.71 (d, 2H, J¼8.7 Hz,
G. J. Med. Chem. 2008, 51, 4899e4910.
14. Racane, L.; Tralic-Kulenovic, V.; Pavlovic, G.; Karminski-Zamola, G. Heterocycles
2006, 68, 1909e1916.
HeAr), 7.98 (d, 2H, J¼8.7 Hz, HeAr), 12.13 (s, 1H, HeNH). 13C NMR
ꢀ
ꢀ
ꢀ
ꢀ
(75 MHz, DMSO-d6):
d
¼162.1 (s), 148.1 (s), 137.4 (s), 127.3 (s), 120.4
(d), 114.3 (s), 111.3 (d), 19.9 (q). LCeMS (ESI): m/z¼310.1 (MHþ).
Anal. Calcd for C16H11N3S2 (309.41): C, 62.11; H, 3.58; N, 13.58.
Found: C, 62.01; H, 3.67; N, 13.66.
15. (a) Buntrock, R. E.; Taylor, E. C. Chem. Rev. 1968, 68, 209e227; (b) Vinogradova,
O. V.; Balova, I. A. Chem. Heterocycl. Compd. 2008, 5, 501e522.
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17. Barton, J. W. Adv. Heterocycl. Chem. 1979, 24, 151e185.
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18. Racane, L.; Tralic-Kulenovic, V.; Mihalic, Z.; Pavlovic, G.; Karminski-Zamola, G.
Tetrahedron 2008, 64, 11594e11602.
19. Cullen, E.; L’Ecuyer, P. Can. J. Chem. 1961, 39, 862e869.
4.12. Computational details
20. Benin, V.;Kaszynski, P.; Pink, M.;Young, V. G., Jr. J. Org. Chem. 2000, 65, 6388e6397.
21. Bhantnagar, I.; George, M. V. J. Org. Chem. 1968, 33, 2407e2411.
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24. (a) Ono, N. The Nitro Group in Organic Synthesis; Wiley-VCH: New York, NY,
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John Wiley: Hoboken, New Jersey, 2007, pp 1815e1819.
25. (a) Nishino, S. F.; Spain, J. C.; He, Z. In Biodegradation of Nitroaromatic Compounds
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7431e7436.
All quantum-mechanical calculations were performed with the
Gaussian 09 program.31 Geometries of all reaction intermediates
and cyclization transition structures of the acid-catalyzed reduc-
tionecyclization mechanism were fully optimized at B3LYP/6-
311þþG(d,p) level of theory, previously established as adequate
for this type of calculation.32 Open-shell species were treated with
a
spin-unrestricted approach (UB3LYP). Nonspecific medium
26. (a) House, H. O. Modern Synthetic Reactions, 2nd ed.; W.A. Benjamin: New York, NY,
1972; p 211; (b) Huang, M.-J.; Leszczynski, J. J. Mol. Struct. (Theochem) 2002, 592,
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effects (in water) were modeled using IEF-PCM method as
implemented in Gaussian 09. At each stationary point, a frequency
calculation was performed at the same level of theory to
characterize the geometry as a minimum or transition structure.
Single-electron transfer reaction energies were calculated from the
corresponding theoretical adiabatic electron affinities and experi-
mental standard Sn4þ/Sn2þ one-electron reduction potential.
Protonation reaction energies were calculated using the proton
solvation value obtained from a cluster-continuum approach.33 As
a check of B3LYP results, IEF-PCM/MP2(fc)/6-311þþG(d,p) single
point calculations at B3LYP geometries were also performed.
Results of these and other calculations, as well as full discussion of
the reductionecyclization mechanism, will be published in a sep-
arate computational paper.
ꢂ
8511e8514; (d) Ung, S.; Falguieres, A.; Guy, A.; Ferroud, C. Tetrahedron Lett. 2005, 46,
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2000, 38, 655e661.
€
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Heyman, M. H.; Suciu, E. J. Org. Chem. 1975, 40, 1395e1405; (c) Vancik, H.;
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28. Boggust, W. A.; Cocker, W. J. Chem. Soc. 1949, 355e361.
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Ferreira, L. F. Helv. Chim. Acta 2005, 88, 1135e1143.
30. Pedersen, D. S.; Rosenbohm, C. Synthesis 2001, 2431e2434.
31. Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.;
Cheeseman, J. R.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. A.;
Nakatsuji, H.; Caricato, M.; Li, X.; Hratchian, H. P.; Izmaylov, A. F.; Bloino, J.;
Zheng, G.; Sonnenberg, J. L.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.;
Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.;
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Acknowledgements
This work was financially supported by Ministry of Science,
Education, and Sports of The Republic of Croatia (grants nos. 117-
0000000-3283, 119-1191342-1339, 125-0982464-1356). The au-
thors would also like to thank The University Computing Centre of
The University of Zagreb (SRCE) for the generous donation of com-
puter time on the Isabella cluster.
€
Salvador, P.; Dannenberg, J. J.; Dapprich, S.; Daniels, A. D.; Farkas, O.; Foresman,
J. B.; Ortiz, J. V.; Cioslowski, J.; Fox, D. J. Gaussian 09, Revision A.02; Gaussian:
Wallingford, CT, 2004.
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Jakubikova, E.; Guthrie, M. G.; Batista, E. R. J. Phys. Chem. A 2009, 113, 6745e6750.
33. Ho, J.; Coote, M. L. Theor. Chem. Acc. 2009, 125, 3e21.