I. Hatial et al. / Tetrahedron Letters 54 (2013) 854–857
857
Figure 4. Docking of biradical intermediates (A) from 1, (B) from 2 and (C) from 3
10. (a) Yang, W.-Y.; Breiner, B.; Kovalenko, S. V.; Ben, C.; Singh, M.; LeGrand, S. N.;
Sang, Q.-X. A.; Strouse, G. F.; Copland, J. A.; Alabugin, I. V. J. Am. Chem. Soc. 2009,
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Breiner, B.; Kaya, K.; Roy, S.; Yang, W.-Y.; Alabugin, I. V. Org. Biomol. Chem.
2012, 10, 3974.
11. (a) Sonogashira, K.; Tohda, Y.; Hagihara, N. Tetrahedron Lett. 1975, 16, 4467–
4470; (b) Takahashi, K.; Kuroyama, Y.; Sonogashira, K.; Hagihara, N. Synthesis
1980, 8, 627.
Table 1
Calculated free energy of binding
Compd
D
Gbinding (Kcal/mol)
1-Biradical
2a-Biradical
3a-Biradical
–9.19
–11.7
–16.86
12. (a) Shain, J. C.; Khamrai, U. K.; Basak, A. Tetrahedron Lett. 1997, 38, 6067; (b)
Basak, A.; Khamrai, U. K.; Mallik, U. Chem. Commun. 1996, 749.
13. (a) Maligres, P. E.; See, M. M.; Askin, D.; Reider, P. J. Tetrahedron Lett. 1997, 38,
5253; (b) Fukuyama, T.; Jow, C.-K.; Cheung, M. Tetrahedron Lett. 1995, 36, 6373.
14. Sheehan, J. C.; Preston, J.; Cruickshank, P. A. J. Am. Chem. Soc. 1965, 87, 2492.
15. Spectroscopic data (1H NMR and 13C NMR recorded at 400 MHz and 100 MHz,
respectively)
Acknowledgement
The author A.B. is grateful to DST, Govt. of India, for funding and
the JC Bose fellowship. I.H. thanks CSIR, Govt. of India for a research
fellowship (NET). DST is also thanked for the funds for a 400 MHz
facility under the IRPHA program.
For 1: dH (d4-CD3OD): 7.42–7.32 (4H, m), 4.19 (2H, s), 3.64, br s), 2.88 (2H, t,
J = 5.0 Hz); dC (d4-CD3OD): 159.5, 128.6, 128.1, 127.8, 127.8, 126.9, 95.3, 88.9,
87.4, 83.4, 49.3, 39.3, 18.4.
For 2: dH (d4-CD3OD): 7.54–7.43 (3H, m), 4.21 (2H, s), 4.12 (2H, s), 3.64 (2H, t,
J = 5.0 Hz), 2.9 (2H, t, J = 5.2 Hz); dC (d4-CD3OD): For isomer I (2a or 2b): 160.5,
134.1, 129.2, 128.9, 128.4, 128.3, 127.6, 96.6, 88.7, 88.3, 88.2, 49.2, 42.2, 39.2,
18.4; For isomer II (2b or 2a): 160.5, 133.3, 129.2, 128.8, 128.4, 128.3, 127.7,
96.8, 88.5, 88.1, 83.3, 49.2, 42.2, 39.2, 18.4; HRMS (done on the mixture) Calcd
for C14H14N2 + H+ 211.1230. Found 211.1230.
For 3: dH (d6-DMSO): 9.73 (1H, br s), 9.08 (1H, s), 8.25 (3H, s), 7.92–7.87 (3H,
m), 7.49–7.27 (3H, m), 4.43–4.23 (2H, m), 4.18 (2H, s), 3.47 (2H, s), 3.14 (1H, s),
2.86–2.82 (2H, m), 2.72–2.70 (3H, m), 1.71 (2H, br s), 1.51 (2H, s), 1.29 (2H, s);
dC (d6-DMSO): For isomer I (3a or 3b): 168.9, 158.9, 140.2, 128.4, 128.2, 127.5,
127.0, 125.8, 98.6, 90.2, 88.3, 83.9, 52.3, 48.9, 42.1, 36.3, 31.2, 30.7, 26.7, 21.6,
18.9. For isomer II (3b or 3a): 163.0, 158.5, 139.5, 130.6, 128.3 127.2, 127.1,
126.8, 98.3, 90.4, 82.3, 83.9, 52.2, 48.9, 42.0, 36.3, 31.2, 30.6, 26.7, 21.6, 18.9;
HRMS (done on the mixture) Calcd for C20H26N4O + H+ 339.2180.1230. Found
339.2178.
Supplementary data
Supplementary data associated with this article can be found, in
References and notes
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