The Journal of Organic Chemistry
NOTE
δ 8.52 (dd, J10,11 = 8.22 Hz, J10,12 = 0.8 Hz, 1H, H-10), 8.24 (s, 1H, H-2),
7.99 (dd, J11,13 = 0.8 Hz, J12,13 = 8.22 Hz, 1H, H-13), 7.85 (d, J6,7 = 8.93
264 (6570), 293 (1871), 306 (1523). IR (cm-1): 3101, 1498, 1243, 960.
1H NMR (300 MHz, CDCl3): δ 8.21 (s, 1H, H-2), 7.82 (d, J6,7 = 8.67
Hz, 1H, H-6/7), 7.62 (d, J6,7 = 8.67 Hz, 1H, H-6/7), 7.49 (d, J11,12 = 5.34
Hz, 1H, H-11/12), 7.47 (d, J11,12 = 5.34 Hz, 1H, H-11/12). 13C NMR
(75 MHz, CDCl3): δ 152.2 (d, C-2), 147.5 (s), 137.9 (s), 125.6
(d, C-11/12), 124.4 (d, C-11/12), 121.1 (d, C-6/7), 108.3 (d, C-6/
7), 106.4 (s), 82.0 (s). HRMS (MALDI-TOF/TOF; m/z): [M þ H]þ
calcd for C9H5NOS 176.0164, found 176.0168.
Hz, 1H, H-6/7), 7.73 (d, J6,7 = 8.93 Hz, 1H, H-6/7), 7.68 (ddd, J10,11
8.22 Hz, J11,12 = 7.24 Hz, J11,13 = 0.8 Hz, 1H, H-11), 7.57 (ddd, J12,13
=
=
8.22 Hz, J11,12 = 7.24 Hz, J10,12 = 0.8 Hz, 1H, H-12). 13C NMR
(151 MHz, CDCl3): δ 151.5 (d, C-2), 147.5 (s), 135.5 (s), 131.2 (s),
128.5 (d, C-13), 127.2 (d, C-11), 126.7 (s), 126.6 (d, C-6/7), 125.5
(d, C-12), 120.0 (d, C-10), 111.0 (d, C-6/7).
Oxazolo[5,4-h]isoquinoline (4). White crystals (0.04 g, 29%). Mp:
8-Methoxynaphtho[1,2-d]oxazole (1b). Pale yellow crystals (0.11 g,
62%). Mp: 71.2-71.5 °C. UV (EtOH; λmax/nm (ε/dm3 mol-1 cm-1)):
231 (55 150), 290 (8350). IR (cm-1): 3094, 1639, 1472, 1242, 821, 694.
1H NMR (600 MHz, CDCl3): δ 8.21 (s, 1H, H-2), 7.87 (d, J12,13 = 8.94
Hz, 1H, H-13), 7.81 (d, J10,12 = 2.52 Hz, 1H, H-10), 7.76 (d, J6,7 = 8.82
166-167 °C. UV (EtOH; λmax/nm (ε/dm3 mol-1 cm-1)): 319 (3818),
1
332 (4294). IR (cm-1): 3094, 1639, 1472, 1242, 821, 694. H NMR
(300 MHz, CDCl3): δ 9.95 (s, 1H, H-10), 8.68 (d, J12,13 = 5.73 Hz, 1H,
H-12), 8.32 (s, 1H, H-2), 7.97 (d, J6,7 = 9.06 Hz, 1, H-6/7), 7.85 (dd,
J12,13 = 5.76 Hz, 1H, H-13), 7.83 (d, J6,7 = 9.06 Hz, 1H, H-6/7). 13C
NMR (75 MHz, CDCl3): δ 152.2 (d, C-2), 147.6 (s, C-5), 146.6
(d, C-10), 142.9 (d, C-12), 134.8 (s), 133.4 (s), 124.5 (d, C-6/7), 120.9
(s, C-4), 120.4 (d, C-13), 115.3 (d, 6/7). HRMS (MALDI-TOF/TOF;
m/z): [M þ H]þ calcd for C10H6N2O 171.0553, found 171.0552.
Procedure for the Synthesis of 5-Styryl-/5-Heteroarylox-
azoles. Compounds 5-8 were prepared from the corresponding acry-
laldehydes (9-12) and 4-toluenesulfonylmethyl isocyanide (TOS-
MIC) as described in the literature for 5-phenyloxazole.9a,b 4-Toluenesul-
fonylmethyl isocyanide (1 eq, 0,005 mol), acryladehyde (1 equiv, 0,005
mol), and potassium carbonate (1 equiv, 0.005 mol) in 30 mL of methanol
were heated under reflux for 3-4 h. After removal of the solvent the residue
was worked up with ice-water and ether. Ether extracts were dried over
anhydrous MgSO4. Evaporation under reduced pressure afforded the crude
product, which was further purified by column chromatography on silica gel
using petroleum ether/ether (variable ratio) as eluent.
Hz, 1H, H-6/7), 7.57 (d, J6,7 = 8.82 Hz, 1H, H-6/7),7.19 (dd, J12,13
=
8.94 Hz, J10,12 = 2.52 Hz, 1H, H-12), 4.01 (s, 3H, H-OCH3). 13C NMR
(151 MHz, CDCl3): δ 159.0 (s), 151.2 (d, C-2), 148.1 (s), 134.8 (s),
130.2 (d, C-13), 128.0 (s), 126.4 (d, C-6/7), 126.3 (s), 118.1 (d, C-12),
108.3 (d, C-6/7), 100.6 (d, C-10), 55.7 (q, C-OCH3). HRMS (MALDI-
TOF/TOF; m/z): [M þ H]þ calcd for C12H9NO2 200.0706, found
200.0710. Anal. Calcd for C12H9NO2: C, 72.35; H, 4.55; N, 7.03. Found:
C, 72.22; H, 4.35; N, 6.80.
6-Methoxynaphtho[1,2-d]oxazole (1c). White crystals (0.13 g, 70%).
Mp: 107.5-108 °C. UV (EtOH; λmax/nm (ε/dm3 mol-1 cm-1)): 297
(2003), 316 (1848), 329 (2308). IR (cm-1): 3107, 2965, 1638,
1
1582, 1458, 1380, 1258. H NMR (300 MHz, CDCl3): δ 8.34 (d, J6,7
= 9.20 Hz, 1H, H-6/7), 8.21 (s, 1H, H-2), 8.09 (d, J11,12 = 8.01 Hz, 1H,
H-10), 7.69 (d, J6,7 = 9.20 Hz, 1, H-6/7), 7.60 (t, J11,12 = J10,11 = 8.01 Hz,
1H, H-11), 6.92 (d, J10,11 = 7.74 Hz, 1H, H-12), 4.05 (s, 3H, H-OCH3).
13C NMR (75 MHz, CDCl3): δ 156.0 (s), 151.4 (d, C-2), 148.0 (s),
135.3 (s), 127.9 (s), 127.8 (d, C-11), 122.9 (s), 120.8 (d, C-6/7), 114.3
(d, C-10), 109.9 (d, C-6/7), 104.1 (d, C-12), 55.6 (q). HRMS (MALDI-
TOF/TOF; m/z): [M þ H]þ calcd for C12H9NO2 200.0706, found
200.0706.
trans-5-Styryloxazole8a (5a). Yellow crystals (0.80 g, 94%). Mp:
60.8-61.1 °C. UV (EtOH; λmax/nm (ε/dm3 mol-1 cm-1)): 227
(10 603), 295 (28 745), 306 (29 990), 321 (21 107). IR (cm-1):
3121, 1684, 1495, 1352, 947, 636. 1H NMR (600 MHz, CDCl3):
4-Methylnaphtho[1,2-d]oxazole (1d). White crystals (0.11 g, 66%).
Mp: 48 °C. UV (EtOH; λmax/nm (ε/dm3 mol-1 cm-1)): 229 (36 250),
280 (7135), 319 (2544). IR (cm-1): 3121, 2920, 1500, 1232, 1085, 959.
1H NMR (600 MHz, CDCl3): δ 8.46 (d, J10,11 = 8.10 Hz, 1H, H-10),
8.22 (s, 1H, H-2), 7.89 (d, J12,13 = 8.10 Hz, 1H, H-13), 7.60 (s, 1H, H-7),
δ 7.85 (s, 1H, H-2), 7.48 (d, J9,10 = 7.38 Hz, 2H, H-9), 7.37 (t, J9,10
=
J
10,11 = 7.38 Hz, 2H, H-10), 7.30 (t, J9,10 = J10,11= 7.38 Hz, 1H, H-11),
7.11 (d, J6,7 = 16.29 Hz, 1H, H-6/7), 7.08 (s, 1H, H-4), 6.92 (d, J6,7
=
16.29 Hz, 1H, H-6/7). 13C NMR (75 MHz, CDCl3): δ 150.5 (d, C-2),
150.3 (s, C-5), 136.2 (s, C-8), 130.3 (d, C-6/7), 128.9 (d, C-10), 128.5
(d, C-11), 126.6 (d, C-9), 124.1 (d, C-4), 112.9 (d, C-6/7).
7.61 (t, J10,11 = J11,12 = 8.10 Hz, 2H, H-7,H-11), 7.52 (t, J11,12 = J12,13
=
8.10 Hz, 1H, H-12), 2.68 (s, 3H, H-CH3). 13C NMR (151 MHz,
CDCl3): δ 150.8 (d, C-2), 147.7 (s), 134.9 (s), 131.1 (s), 127.3
(d, C-13), 125.7 (d, C-7), 125.3 (d, C-11), 125.0 (d, C-12), 124.9 (s),
121.4 (d, C-10), 121.1 (s), 15.2 (q). HRMS (MALDI-TOF/TOF; m/z):
[M þ H]þ calcd for C12H9NO 184.0757, found 184.0757.
trans-5-(4-Methoxystyryl)oxazole (5b). Pale yellow crystals (0.91 g,
90%). Mp: 103.5-104.0 °C. UV(EtOH;λmax/nm (ε/dm3 mol-1 cm-1)):
229 (10 573), 307 (31 474), 318 (32 742). IR (cm-1): 3109, 1603, 1508,
1
1244, 951, 640. H NMR (600 MHz, CDCl3): δ 7.82 (s, 1H, H-2),
7.42 (d, J9,10 = 8.46 Hz, 2H, H-9), 7.05 (d, J6,7 = 16.26 Hz, 1H, H-6/7),
6.78 (d, J6,7 = 16.26 Hz, 1H, H-6/7), 7.02 (s, 1H, H-4), 6.90 (d, J9,10
Furo[3,2-e]benzoxazole (2). White crystals (0.09 g, 63%). Mp: 39-
40 °C. IR (cm-1): 3105, 2918, 2848, 1506, 1095, 795. 1H NMR
(600 MHz, CDCl3): δ 8.19 (s, 1H, H-2), 7.78 (d, J10,11 = 2.13 Hz,
1H, H-11), 7.57 (dd, J6,7 = 8.85 Hz, J7,10 = 0.8 Hz, 1H, H-7), 7.52
(d, J6,7= 8.85 Hz, 1H, H-6), 7.20 (dd, J10,11 = 2.1 Hz, J7,10 = 0.8 Hz, 1H,
H-10). 13C NMR (151 MHz, CDCl3): δ 153.0 (s), 152.6 (d), 146.7 (s),
146.2 (d), 133.0 (s), 119.6 (s), 109.2 (d), 106.5 (d), 104.6 (d). HRMS
(MALDI-TOF/TOF; m/z): [M þ H]þ calcd for C9H5NO2 160.0393,
found 160.0395.
=
8.46 Hz, 2H, H-10), 3.83 (s, 3H, H-OCH3). 13C NMR (151 MHz,
CDCl3): δ 159.9 (s, C-11), 150.8 (s, C-5), 150.0 (d, C-2), 129.9 (d, C-7),
129.0 (s, C-8), 127.9 (d, C-9), 123.3 (d, C-4), 114.3 (d, C-10), 110.9
(d, C-6), 55.3 (q, C-OCH3). HRMS (MALDI-TOF/TOF; m/z):
[M þ H]þ calcd for C12H11NO2 202.0863, found 202.0860. Anal. Calcd
for C12H11NO2: C, 71.63; H, 5.51; N, 6.96. Found: C, 71.36; H, 5.36;
N, 6.59.
trans-5-(2-Methoxystyryl)oxazole (5c). White crystals (0.65 g, 65%).
Mp: 71.4-71.6 °C. UV (EtOH; λmax/nm (ε/dm3 mol-1 cm-1)): 234
(7033), 291 (14 606), 302 (14 350), 318 (13 943), 329 (14 553). IR
Thieno[3,2-e]benzoxazole (3a). Yellow crystals (0.09 g, 59%). Mp:
40-43 °C. UV (EtOH; λmax/nm (ε/dm3 mol-1 cm-1)): 247 (1619), 267
(2977), 276 (2907), 296 (2837), 308 (3604). IR (cm-1): 3117, 1740, 1398,
1238, 1022. 1H NMR (600 MHz, CDCl3): δ 8.19 (s, 1H, H-2), 7.86 (d, J6,7
= 8.75 Hz, 1H, H-6/7), 7.85 (d, J10,11 = 5.40 Hz, 1H, H-10/11), 7.66 (d,
J10,11 = 5.40 Hz, 1, H-10/11), 7.61 (d, J6,7 = 8,79 Hz, 1H, H-6/7). 13C NMR
(75 MHz, CDCl3): δ 151.9 (d, C-2), 147.8 (s), 136.9 (s), 134.7 (s), 132.0
(s), 128.8 (d), 120.6 (d), 119.6 (d), 108.0 (d). HRMS (MALDI-TOF/
TOF; m/z): [M þ H]þ calcd for C9H5NOS 176.0164, found 176.0163.
Thieno[2,3-e]benzoxazole (3b). Yellow oil (0.07 g, 41%). UV
(EtOH; λmax/nm (ε/dm3 mol-1 cm-1)): 236 (25 022), 242 (22 150),
1
(cm-1): 3142, 2942, 2837, 1579, 1470, 1238. H NMR (300 MHz,
CDCl3): δ 7.83 (s, 1H, H-2), 7.49 (dd, J9,10 = 8.30 Hz, J9,11 = 1.29 Hz,
1H, H-9), 7.40 (d, J6,7 = 16.6 Hz, 1H, H-6/7), 7.27 (dt, J9,11 = 1.29 Hz,
J10,11 = J11,12 = 8.30 Hz, 1H, H-11), 7.05 (s, 1H, H-4), 7.00 (d, J6,7
16.60 Hz, 1H, H-6/7), 6.97 (t, J9,10 = J10,11 = 8.30 Hz, 1H, H-10), 6.91
(d, J11,12 = 8.30 Hz, 1H, H-12), 3.90 (s, 3H, H-OCH3). 13C NMR
(75 MHz, CDCl3): δ 157.3 (s, C-13), 151.1 (s, C-5), 150.2 (d, C-2),
129.4 (d, C-11), 127.2 (d, C-12), 125.6 (d, C-6/7), 125.1 (s, C-8), 123.7
(d, C-4), 120.8 (d, C-10), 113.6 (d, C-6/7), 111.0 (d, C-9), 55.5
=
2906
dx.doi.org/10.1021/jo1025942 |J. Org. Chem. 2011, 76, 2904–2908