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N. Barbero et al. / Tetrahedron 63 (2007) 10425–10432
J¼6.2, 2.9 Hz, 1H), 7.82 (dd, J¼6.4, 2.6 Hz, 1H), 7.84–7.91
(m, 1H), 7.96 (dd, J¼8.6, 5.0 Hz, 2H), 8.31 (d, J¼8.6 Hz,
1H), 8.76 (s, 1H); 13C NMR (75 MHz, CDCl3) d (ppm)
110.5, 120.0, 123.9, 124.6, 125.1, 126.8, 127.7, 127.8,
128.1, 128.7, 128.9 (CH), 124.3, 132.9, 134.7, 142.2,
150.8, 163.1 (C). MS (EI) m/z: 246 (M+1, 8), 245 (M,
100), 244 (11), 69 (11). HRMS (EI): calculated for
C17H11NO, 245.0841; found, 245.0840.
(CH3), 110.5, 119.1, 125.9, 128.1, 129.5, 129.8 (CH),
135.5, 139.7, 150.6, 158.5 (C). MS (EI) m/z: 216 (M+1,
99), 215 (M, 100), 214 (99), 213 (81), 186 (99), 185 (79),
111 (99), 108 (85), 95 (99), 78 (99), 77 (99), 69 (97), 63
(99), 52 (99), 51 (98). HRMS (EI): calculated for
C12H9NOS, 215.0405; found, 215.0409.
3.2.10. 2-(2-Thienyl)benzo[d]oxazole (2j) (Table 2, entries
18–20). The typical procedure was followed starting from
the corresponding 20-chloroanilide (99.0 mg, 0.42 mmol)
and CuCl (3.7 mg, 0.037 mmol) to afford benzo[d]oxazole
2j (43.5 mg, 52%) as a white solid.
3.2.7. 6-Methyl-2-(2-naphthyl)benzo[d]oxazole (2g)
(Table 2, entries 13 and 14). The typical procedure was fol-
lowed starting from the corresponding 20-chloroanilide
(101.8 mg, 0.34 mmol) and CuCl (3.1 mg, 0.031 mmol) to
afford benzo[d]oxazole 2g (57.6 mg, 64%) as a white solid.
The typical procedure was followed starting from the corre-
sponding 20-bromoanilide (99.6 mg, 0.35 mmol) and CuCl
(3.3 mg, 0.033 mmol) to afford benzo[d]oxazole 2j
(36.8 mg, 52%) as a white solid.
The typical procedure was followed starting from the
corresponding 20-bromoanilide (102.0 mg, 0.30 mmol) and
Cu(OTf)2 (12.5 mg, 0.034 mmol) to afford benzo[d]oxazole
2g (50.3 mg, 65%) as a white solid. Mp 130–132 ꢀC (hexane);
IR (KBr): n (cmꢁ1) 3249, 3049, 2920, 1649, 1502, 1302,
The typical procedure was followed starting from the corre-
sponding o-iodobenzenamide (103.3 mg, 0.32 mmol) and
Cu(OTf)2 (13.3 mg, 0.037 mmol) to afford benzo[d]oxazole
2j (17.9 mg, 30%) as a white solid. Mp 97–99 ꢀC (hexane)
(lit.15a 81–82 ꢀC).
1
1043; H NMR (300 MHz, CDCl3) d (ppm) 2.52 (s, 3H),
7.18 (d, J¼8.1 Hz, 1H), 7.40 (s, 1H), 7.50–7.61 (m, 2H),
7.67 (d, J¼8.1 Hz, 1H), 7.83–7.91 (m, 1H), 7.96 (dd,
J¼8.9, 5.6 Hz, 2H), 8.29 (dd, J¼8.6, 1.6 Hz, 1H), 8.74 (s,
1H); 13C NMR (75 MHz, CDCl3) d (ppm) 21.8 (CH3),
110.7, 119.3, 123.8, 125.8, 126.8, 127.6, 127.8, 127.9,
128.7, 128.8 (CH), 124.5, 132.9, 134.6, 135.6, 140.0, 151.1,
162.6 (C). MS (EI) m/z: 260 (M+1, 76), 259 (M, 100), 258
(90), 230 (64), 219 (69), 153 (81), 127 (54), 78 (48). HRMS
(EI): calculated for C18H13NO, 259.0997; found, 259.0994.
3.2.11. 2-(2-Thienyl)-6-(trifluoromethoxy)benzo[d]ox-
azole (2k) (Table 2, entry 21). The typical procedure was
followed starting from the corresponding 20-bromoanil-
ide (100.4 mg, 0.27 mmol) and Cu(OTf)2 (11.8 mg,
0.032 mmol) to afford benzo[d]oxazole 2k (23.3 mg, 30ꢁ%1)
as a white solid. Mp 73–78 ꢀC (hexane); IR (KBr): n (cm
)
3096, 2908, 1614, 1573, 1473, 1255, 1155; 1H NMR
(300 MHz, CDCl3) d (ppm) 7.22 (dd, J¼12.7, 8.7 Hz, 2H),
7.46 (s, 1H), 7.59 (d, J¼4.9 Hz, 1H), 7.71 (d, J¼8.7 Hz,
1H), 7.91 (d, J¼8.7 Hz, 1H); 13C NMR (75 MHz, CDCl3)
d (ppm) 104.5, 118.4, 120.0, 128.4, 130.4, 130.8 (CH),
120.5 (q, J¼257.5 Hz), 129.0, 140.7, 146.3 (q, J¼2.1 Hz),
150.2, 160.4 (C). MS (EI) m/z: 286 (M+1, 19), 285 (100),
284 (53), 207 (11), 191 (13). HRMS (EI): calculated for
C12H6F3NO2S, 285.0071; found, 285.0083.
3.2.8. 2-(2-Naphthyl)-6-(trifluoromethoxy)benzo[d]ox-
azole (2h) (Table 2, entry 15). The typical procedure was
followed starting from the corresponding 20-bromoanil-
ide (101.3 mg, 0.25 mmol) and Cu(OTf)2 (10.5 mg,
0.029 mmol) to afford benzo[d]oxazole 2h (45.9 mg, 57%)
as a white solid. Mp 86–89 ꢀC (hexane); IR (film): n
(cmꢁ1) 1614, 1543, 1361, 1244, 1114, 1038; 1H NMR
(300 MHz, CDCl3) d (ppm) 7.25 (d, J¼6.5 Hz, 1H), 7.50
(s, 1H), 7.52–7.62 (m, 2H), 7.75 (d, J¼8.7 Hz, 1H), 7.80–
7.91 (m, 1H), 7.95 (dd, J¼8.7, 4.1 Hz, 2H), 8.24 (dd,
J¼8.6, 1.3 Hz, 1H), 8.71 (s, 1H); 13C NMR (75 MHz,
CDCl3) d (ppm) 104.5, 118.3, 120.2, 123.7, 126.9, 127.9,
128.0, 128.3, 128.8, 128.9 (CH), 132.8, 134.8, 140.8,
146.3, 146.4, 150.52, 164.6 (C). MS (EI) m/z: 330 (M+1,
8), 329 (M, 100), 260 (33), 127 (4). HRMS (EI): calculated
for C18H10F3NO2, 329.0664; found, 329.0670.
3.2.12. 2-(3-Thienyl)benzo[d]oxazole (2l) (Table 2, entries
22 and 23). The typical procedure was followed starting
from the corresponding 20-chloroanilide (57.6 mg,
0.24 mmol) and Cu(OTf)2 (10.5 mg, 0.029 mmol) to afford
benzo[d]oxazole 2l (19.6 mg, 40%) as a white solid.
The typical procedure was followed starting from the corre-
sponding 20-bromoanilide (99.3 mg, 0.35 mmol) and
Cu(OTf)2 (14.6 mg, 0.040 mmol) to afford benzo[d]oxazole
2l (41.9 mg, 59%) as a white solid. Mp 136–139 ꢀC (hex-
ane); IR (film): n (cmꢁ1) 3084, 2920, 1614, 1572, 1449,
3.2.9. 6-Methyl-2-(2-thienyl)benzo[d]oxazole (2i) (Table
2, entries 16 and 17). The typical procedure was fol-
lowed starting from the corresponding 20-chloroanilide
(100.9 mg, 0.40 mmol) and CuCl (3.4 mg, 0.035 mmol) to
afford benzo[d]oxazole 2i (50.6 mg, 59%) as a white solid.
1
1402, 1243, 1056; H NMR (300 MHz, CDCl3) d (ppm)
7.29–7.40 (m, 2H), 7.44 (dd, J¼4.8, 3.0 Hz, 1H), 7.49–
7.60 (m, 1H), 7.72–7.77 (m, 1H), 7.79 (dd, J¼5.1, 0.6 Hz,
1H), 8.19 (d, J¼2.3 Hz, 1H); 13C NMR (75 MHz, CDCl3)
d (ppm) 110.4, 119.8, 124.5, 125.0, 126.6, 127.0, 128.0
(CH), 129.2, 141.9, 150.3, 159.7 (C). MS (EI) m/z: 201
(M, 22), 64 (25), 63 (100). HRMS (EI): calculated for
C11H7NOS, 201.0248; found, 201.0243.
The typical procedure was followed starting from the
corresponding 20-bromoanilide (100.4 mg, 0.34 mmol) and
Cu(OAc)2 (8.5 mg, 0.042 mmol) to afford benzo[d]oxazole
2i (39.2 mg, 54%) as a white solid. Mp 66–69 ꢀC (hexane);
IR (film): n (cmꢁ1) 3096, 2920, 1608, 1557, 1485, 1420,
1
1250, 1050; H NMR (300 MHz, CDCl3) d (ppm) 2.49 (s,
3H), 7.16 (t, J¼5.2 Hz, 2H), 7.33 (s, 1H), 7.52 (dd, J¼4.9,
1.0 Hz, 1H), 7.59 (d, J¼8.1 Hz, 1H), 7.87 (dd, J¼3.6,
1.0 Hz, 1H); 13C NMR (75 MHz, CDCl3) d (ppm) 21.75
3.2.13. 6-Methyl-2-(3-thienyl)benzo[d]oxazole (2m)
(Table 2, entries 24 and 25). The typical procedure was
followed starting from the corresponding 20-chloroanilide