3534
G.H. Sung et al. / Tetrahedron 69 (2013) 3530e3535
water, and then, with saturated NaCl solution (40 mLꢁ6) and finally,
dried over anhydrous magnesium sulfate. After evaporating the
solvent under reduced pressure, the resulting residue was trans-
ferred an open-bed silica gel column (4ꢁ9 cm). The column was
eluted with n-hexane/ethyl acetate (3:1, v/v) for compound 4 and
then with ethyl acetate for 4,5-dichloropyridazin-3(2H)-one. Frac-
tions containing 4 were combined and evaporated under reduced
pressure to give 4. Fractions containing 4,5-dichloropyridazin-
3(2H)-one were also combined and evaporated under reduced
pressure to afford recyclable 4,5-dichloropyridazin-3(2H)-one.
1343, 1269, 1241, 1156, 1125, 1101, 1007, 932, 888, 864, 834, 791, 742,
606 cmꢂ1. 1H NMR (DMSO-d6,
ppm) 1.24e1.42 (m, 3H), 1.61e1.80
(m, 5H), 2.06e2.11 (m, 2H), 2.97e3.02 (m, 1H), 7.32e7.38 (m, 2H),
7.65e7.72 (m, 2H). 13C NMR (DMSO-d6,
ppm) 24.95, 25.37, 29.98,
d
d
36.90, 110.47, 119.36, 124.11, 124.56, 140.95, 150.10, 169.63. HRMS
(m/z): [M]þ calcd for C13H15NO 201.1154. Found: 201.1154.
Acknowledgements
This research was supported by Basic Science Research
Program through the National Research Foundation of Korea (NRF)
funded by the Ministry of Education, Science and Technology
(2012RIAIA2001162).
4.3.1. 2-Phenylbenzo[d]oxazole (4a). White solid. Mp 101e102 ꢀC
(lit.19 101e102 ꢀC). IR (KBr) 3061, 2955, 1612, 1549, 1479, 1446, 1341,
1318, 1283, 1239, 1192, 1144, 1109, 1078, 1048, 1017, 922, 888, 858,
807, 741, 693, 689, 629 cmꢂ1. 1H NMR (DMSO-d6,
d
ppm) 7.44e7.47
References and notes
(m, 2H), 7.63e7.65 (m, 3H), 7.77e7.87 (m, 2H), 8.23e8.26 (m, 2H).
13C NMR (DMSO-d6,
d ppm) 110.90, 119.87, 124.84, 125.48, 126.54,
1. (a) Lion, C. J.; Matthews, C. S.; Wells, G.; Bradshaw, T. D.; Stevens, M. F. G.;
Westwell, A. D. Bioorg. Med. Chem. 2006, 16, 5005; (b) Vicni, P.; Geronikaki, A.;
Incerti, M.; Busonera, B.; Poni, G.; Cabras, C. A.; Colla, P. L. Bioorg. Med. Chem.
2003, 11, 4785; (c) Zajac, M.; Hornbarik, P.; Magdolen, P.; Foltinova, P.;
Zaharadnik, P. Tetrahedron 2008, 64, 10605; (d) Cressier, D.; Prouillac, C.;
Hernandez, P.; Amourette, C.; Diserbo, M.; Lion, C.; Rima, G. Bioorg. Med. Chem.
2009, 17, 5275.
2. For selected recent examples, see: (a) Wang, H. Y.; Chen, G.; Xu, X. P.; Ji, S. J.
Synth. Met. 2010, 160, 1065; (b) Park, M. J.; Kwak, J.; Lee, J.; Jung, I. H.; Kong, H.;
Lee, C.; Hwang, D. H.; Shim, H. K. Macromolecules 2010, 43, 1379; (c) Esashika,
K.; Yoshizawa-Fujita, M.; Takeoka, Y.; Rikukawa, M. Synth. Met. 2009, 159, 2184;
(d) Yao, S.; Ahn, H. Y.; Wang, X.; Fu, J.; van Stryland, E. W.; Hagan, D. J.; Belfield,
K. D. J. Org. Chem. 2010, 75, 3965; (e) Bahrami, K.; Khodaei, M. M.; Naali, F. J. Org.
Chem. 2008, 73, 6835; (f) Sun, Y.; Duan, L.; Wei, P.; Qiao, J.; Dong, G.; Wang, L.;
Qiu, Y. Org. Lett. 2009, 11, 2069.
127.29, 129.26, 131.88, 141.63, 150.30, 162.29. HRMS (m/z): [M]þ
calcd for C13H9NO 195.0684. Found: 195.0690.
4.3.2. 2-(4-Methoxyphenyl)benzo[d]oxazole (4b). White solid. Mp
98e99 ꢀC (lit.20 97e99 ꢀC). IR (KBr) 3044, 2951, 2910, 2840, 1613,
1578, 1498, 1449, 1417, 1341, 1315, 1240, 1185, 1165, 1104, 1055, 1014,
918, 828, 780, 734, 628 cmꢂ1. 1H NMR (DMSO-d6,
d ppm) 3.88 (s, 3H),
7.16 (d, 2H, J¼8.69 Hz), 7.39e7.42 (m, 2H), 7.74e7.79 (m, 2H), 8.15 (d,
2H, J¼8.68 Hz). 13C NMR (DMSO-d6,
d ppm) 55.45, 110.63, 114.70,
118.75, 119.38, 124.63, 124.90, 129.08, 141.70, 150.10, 162.13, 162.36.
HRMS (m/z): [M]þ calcd for C14H11NO2 225.0790. Found: 225.0790.
3. For selected recent examples, see: (a) Chen, Y. X.; Qian, I. F.; Zhang, W.; Han, B.
Angew. Chem., Int. Ed. 2008, 47, 9330; (b) Chakraorti, A. K.; Rudrawar, S.; Jadhav,
K. B.; Kaur, G.; Chankeswara, S. V. Green Chem. 2007, 9, 1335; (c) Li, Y.; Wang,
Y.-L.; Wang, J. Y. Chem. Lett. 2006, 35, 460; (d) Moghaddam, F. M.; Ismaili, H.;
Bardajee, G. R. Heteroat. Chem. 2006, 17, 136; (e) Batista, R. M. F.; Costa, S. P. G.;
Raposo, M. M. M. Tetrahedron Lett. 2004, 45, 2825; (f) Ranu, B. C.; Jana, R.; Dcy, S.
Chem. Lett. 2004, 33, 274; (g) Itoh, T.; Nagata, K.; Ishikawa, H.; Ohsawa, A.
Heterocycles 2004, 62, 197.
4. (a) Rudrawar, S.; Kondaskar, A.; Chakrabori, A. K. Synthesis 2005, 2521; (b)
Chen, C.; Chen, Y. J. Tetrahedron Lett. 2004, 45, 113; (c) Mourtas, S.; Gatos, D.;
Barlos, K. Tetrahedron Lett. 2001, 42, 2201; (d) Chakraborti, A. K.; Selvam, C.;
Kaur, G.; Bhagat, S. Synlett 2004, 851; (e) Yildiz-Oren, I.; Yalcin, I.; Aki-Sener, E.
Eur. J. Med. Chem. 2004, 39, 291.
4.3.3. 2-(4-Bromophenyl)benzo[d]oxazole (4c). Light yellow solid.
Mp 157e158 ꢀC (lit.21 157e158 ꢀC). IR (KBr) 2952, 2927, 2895, 2853,
1612, 1592, 1548, 1458, 1398, 1375, 1342, 1294, 1275, 1242, 1196,
1175, 1109, 1068, 1050, 1005, 925, 890, 830, 808, 739, 625 cmꢂ1. 1H
NMR (DMSO-d6,
d
ppm) 7.43e7.47(m, 2H), 7.79e7.85(m, 4H),
ppm) 110.94, 119.87,
8.12e8.15(m, 2H). 13C NMR (DMSO-d6,
d
124.98, 125.57, 125.74, 129.08, 132.36, 141.34, 150.19, 161.40. HRMS
(m/z): [M]þ calcd for C13H8BrNO 272.9789. Found: 272.9785.
5. (a) Laskar, I. R.; Chen, M. T. Chem. Mater. 2004, 16, 117; (b) Nadaf, R. N.; Siddiqui,
S. A.; Daniel, T.; Lahoti, R. J.; Srinivasan, K. V. J. Mol. Catal. A: Chem. 2004, 214,
155.
6. Matsushita, H.; Lee, S. H.; Joung, M.; Clapham, B.; Janda, K. D. Tetrahedron Lett.
2004, 45, 313.
7. (a) Downer-Riley, N. K.; Jackson, Y. A. Tetrahedron 2008, 64, 7741; (b) Itoh, T.;
Mase, T. Org. Lett. 2007, 9, 3687; (c) Evindar, G.; Batey, R. A. J. Org. Chem.
2006, 71, 1802; (d) Moghaddani, F. M.; Boeini, H. Z. Synlett 2005, 1612; (e)
Mu, X. Z.; Zou, J. P.; Zeng, R. S.; Wu, J. C. Tetrahedron Lett. 2005, 46, 4345; (f)
Joyce, I. I.; Evindar, G.; Batey, R. A. Chem. Commun. 2004, 446; (g) Benedi, C.;
Bravo, F.; Uriz, P.; Fernadez, E.; Claver, C.; Castillon, S. Tetrahedron Lett. 2003,
44, 6073.
4.3.4. 2-(Furan-2-yl)benzo[d]oxazole (4d). Light yellow solid. Mp
85e86 ꢀC (lit.22 85e86 ꢀC). IR (KBr) 3107, 3062, 3040, 1640, 1586,
1532, 1474, 1447, 1391, 1338, 1296, 1241, 1154, 1108, 1079, 1057, 1011,
935, 898, 880, 826, 791, 756, 739, 620 cmꢂ1 1H NMR (DMSO-d6,
.
d
ppm) 6.86e6.88 (m, 1H), 7.43e7.51 (m, 3H), 7.78e7.84 (m, 2H),
8.14 (s, 1H). 13C NMR (DMSO-d6,
d ppm) 110.86, 112.79, 115.10,
119.80, 125.06, 125.56, 141.21, 141.68, 147.09, 149.61, 154.69. HRMS
(m/z): [M]þ calcd for C11H7NO2 185.0477. Found: 185.0478.
8. Trost, B. M. Angew. Chem., Int. Ed. Engl. 1995, 34, 259.
4.3.5. 2-Ethylbenzo[d]oxazole (4e). Yellow oil. IR (KBr) 3061, 2981,
2935, 2880, 2848, 1612, 1570, 1517, 1453, 1372, 1286, 1264, 1239,
1156, 1102, 1066, 1027, 1001, 969, 924, 889, 822, 747, 624 cmꢂ1. 1H
9. (a) Sung, G. H.; Kim, B. R.; Lee, S. G.; Kim, J. J.; Yoon, Y. J. Curr. Org. Chem. 2012,
16, 852; (b) Lee, S. G.; Kim, J. J.; Kim, H. K.; Kweon, D. H.; Kang, Y. J.; Cho, S. D.;
Kim, S. K.; Yoon, Y. J. Curr. Org. Chem. 2004, 8, 1463; (c) Kim, S. K.; Kweon, D. H.;
Cho, S. D.; Kang, Y. J.; Park, K. H.; Lee, S. G.; Yoon, Y. J. J. Heterocycl. Chem. 2005,
42, 353.
10. (a) Hwang, J.; Hwang, Y.; Yang, K.; Yoon, Y. J.; Koo, I. S. Bull. Korean Chem. Soc.
2009, 30, 2779; (b) Lee, H. G.; Kim, M. J.; Park, S. E.; Kim, J. J.; Kim, B. R.; Lee, S.
G.; Yoon, Y. J. Synlett 2009, 2809; (c) Kim, J. J.; Park, Y. D.; Kim, H. K.; Cho, S. D.;
Kim, J. K.; Lee, S. G.; Yoon, Y. J. Synth. Commun. 2005, 35, 731; (d) Park, Y. D.;
Kim, J. J.; Kim, H. K.; Cho, S. D.; Kang, Y. J.; Park, K. H.; Lee, S. G.; Yoon, Y. J. Synth.
Commun. 2005, 35, 371; (e) Kim, J. J.; Park, Y. D.; Cho, S. D.; Kim, H. K.; Kang, Y.
J.; Lee, S. G.; Falck, J. R.; Shiro, M.; Yoon, Y. J. Bull. Korean Chem. Soc. 2004, 25,
1273; (f) Park, Y. D.; Kim, J. J.; Chung, H.-A.; Kweon, D. H.; Cho, S. D.; Lee, S. G.;
Yoon, Y. J. Synthesis 2003, 560; (g) Kang, Y. J.; Chung, H.-A.; Kim, J. J.; Yoon, Y. J.
Synthesis 2002, 733.
NMR (DMSO-d6,
d
ppm) 1.27e1.40 (m, 3H), 2.87e3.00 (m, 2H),
ppm)
7.28e7.36 (m, 2H), 7.62e7.70 (m, 2H). 13C NMR (DMSO-d6,
d
10.67, 21.43, 110.40, 119.21, 124.13, 124.55, 141.03, 150.30, 167.81.
HRMS (m/z): [M]þ calcd for C9H9NO 147.0684. Found: 147.0687.
4.3.6. 2-Hexylbenzo[d]oxazole (4f). Yellow oil. IR (KBr) 2955, 2928,
2856, 1615, 1573, 1455, 1439, 1378, 1345, 1264, 1241, 1149, 1103, 1002,
928, 836, 816, 745, 621 cmꢂ1. 1H NMR (DMSO-d6,
d ppm) 0.85 (t, 3H,
J1¼6.97 Hz, J2¼6.73 Hz), 1.24e1.38 (m, 6H), 1.76e1.85 (m, 2H), 2.90 (t,
11. Kim, S. K.; Cho, S. D.; Kweon, D. H.; Yoon, Y. J.; Kim, J. H.; Heo, J. N. J. Heterocycl.
Chem. 1997, 34, 209.
12. Huang, X.; Tang, J. Tetrahedron 2003, 59, 4851.
13. Lim, H.-J.; Myung, D.; Lee, I. Y. C.; Jung, M. H. J. Comb. Chem. 2008, 10, 501.
14. Okimoto, M.; Yoshida, T.; Hoshi, M.; Hattori, K.; Komata, M.; Tomozawa, K.;
Chiba, T. Heterocycles 2008, 75, 35.
2H, J1¼7.52 Hz, J2¼7.49 Hz), 7.30e7.34 (m, 2H), 7.59e7.64 (m, 1H),
7.70e7.73 (m, 1H). 13C NMR (DMSO-d6,
d ppm) 14.00, 22.37, 26.51,
28.18, 28.63, 31.32, 110.49, 119.52, 124.21, 124.62,141.58, 150.71, 166.97.
HRMS (m/z): [M]þ calcd for C13H17NO 203.1310. Found: 203.1312.
15. Wang, Z.; Tang, R.; Li, J. Chin. J. Chem. 2011, 29, 314.
16. Jin, H.-L.; Cheng, T.-X.; Chen, J.-X. Appl. Organomet. Chem. 2011, 25, 238.
17. Maleki, B.; Salehabadi, H. Eur. J. Chem. 2010, 1, 377.
4.3.7. 2-Cyclohexylbenzo[d]oxazole (4g). Light yellow solid. Mp
35e36 ꢀC (lit.23 35 ꢀC). IR (KBr) 2930, 2854, 1609, 1565, 1451, 1375,