6
X. Zhang et al. / Tetrahedron xxx (2014) 1e9
J¼7.0 Hz, 3H); 13C NMR (125 MHz, CDCl3)
d
168.2,150.9,141.5,124.5,
under reduced pressure to give a yellow solid. 1H NMR analyses of
the crude showed complete disappearance of the starting materials
and formation of the desired ortho-aminoaryl NeH ketimines. The
crude ketimine was dissolved in 0.4 mL of MeOH and PhI(OAc)2
(0.3 mmol, 97 mg) was added to the reaction mixture. After stirring
at room temperature for 16 h, the solvent was removed under re-
duced pressure and the crude was purified by chromatography on
silica gel (eluent: pentane/EtOAc).
124.2,119.7,110.4, 22.3,11.0; HRMS (ESI) Calcd for C9H10NO [MþH]þ
148.0762, Found 148.0759; FTIR (neat) cmꢁ1 3057, 2982, 2940,
2878, 1616, 1572, 1451, 1372, 1238, 1168, 1148, 1008, 921, 823, 764,
742. All physical and spectroscopic data were in complete agree-
ment with the reported ones.27
4.2.9. 2-Propylbenzo[d]oxazole (2i). Colorless oil. Yield¼71%
(114 mg). 1H NMR (500 MHz, CDCl3)
d 7.68e7.66 (m, 1H), 7.48e7.46
(m,1H), 7.29e7.27 (m, 2H), 2.91 (t, J¼7.5 Hz, 2H),1.92 (sext, J¼7.5 Hz,
4.3.1. 2-Methyl-1-tosyl-benzo[d]imidazole (5a). Compound 5a was
obtained as a colorless solid according to general procedure 4.3,
method A. Yield¼74% (53 mg). Mp 110e112 ꢀC; previously reported
2H), 1.05 (t, J¼7.5 Hz, 3H); 13C NMR (125 MHz, CDCl3)
d 167.3, 151.0,
141.6, 124.5, 124.2, 119.7, 110.4, 30.7, 20.4, 13.9; HRMS (ESI) Calcd for
C
10H12NO [MþH]þ 162.0919, Found 162.0912; FTIR (neat) cmꢁ1
113e114 ꢀC.32 1H NMR (300 MHz, CDCl3)
d 8.06e8.00 (m,1H), 7.81 (d,
3057, 2965, 2929, 2875,1608,1566,1463,1429,1381,1269,1241,1157,
1145, 1098, 1000, 932, 865, 834, 767, 742. All physical and spectro-
scopic data were in complete agreement with the reported ones.30
J¼8.4 Hz, 2H), 7.66e7.61 (m,1H), 7.37e7.31 (m, 2H), 7.29 (d, J¼8.4 Hz,
2H), 2.82 (s, 3H), 2.39 (s, 3H); 13C NMR (75 MHz, CDCl3)
d
151.5,146.2,
141.9, 135.5, 133.3, 130.4 (2C), 129.9 (2C), 124.9, 124.8, 119.7, 113.6,
21.8, 17.0; HRMS (ESI) Calcd for C15H15N2O2S [MþH]þ 287.0854,
Found 287.0858; FTIR (neat) cmꢁ1 2924,1543,1492,1370,1245,1187,
1160, 1087, 1052, 1015, 913, 810, 661, 541. All physical and spectro-
scopic data were in complete agreement with the reported ones.33
4.2.10. 2-Phenylbenzo[d]oxazole (2j). Colorless solid. Yield¼58%
(113 mg). Mp 100e101 ꢀC; previously reported 101e103 ꢀC.16g 1H
NMR (300 MHz, CDCl3)
7.62e7.57 (m, 1H), 7.55e7.51 (m, 3H), 7.39e7.33 (m, 2H); 13C NMR
(75 MHz, CDCl3) 163.2, 150.9, 142.2, 131.7, 129.0 (2C), 127.8 (2C),
d 8.29e8.26 (m, 2H), 7.82e7.75 (m, 1H),
d
4.3.2. 2,5-Dimethyl-1-tosyl-benzo[d]imidazole (5b). Compound 5b
was obtained as a colorless solid according to general procedure
4.3, method A. Yield¼81% (61 mg). Mp 150 ꢀC; 1H NMR (300 MHz,
127.2, 125.2, 124.7, 120.1, 110.7; HRMS (ESI) Calcd for C13H10NO
[MþH]þ 196.0762, Found 196.0758; FTIR (neat) cmꢁ1 1616, 1551,
1446, 1240, 1051, 923, 779, 684, 626, 485. All physical and spectro-
scopic data were in complete agreement with the reported ones.27
CDCl3)
d
7.90 (d, J¼8.4 Hz, 1H), 7.81 (d, J¼8.2 Hz, 1H), 7.42 (s, 1H),
7.29 (d, J¼8.2 Hz, 2H), 7.17 (d, J¼8.4 Hz,1H), 2.81 (s, 3H), 2.45 (s, 3H),
2.39 (s, 3H); 13C NMR (75 MHz, CDCl3)
d
151.5, 146.0, 142.1, 135.5,
4.2.11. 3-Phenyl-1,2-benzisoxazole (3j). Colorless oil. Yield¼30%
134.7, 131.2, 130.3 (2C), 126.9 (2C), 126.1, 119.7, 113.1, 21.8, 21.5, 17.0;
(59 mg). 1H NMR (300 MHz, CDCl3)
d
8.01e7.95 (m, 3H), 7.68e7.50
HRMS (ESI) Calcd for
C
16H16N2O2S [MþH]þ 301.1011, Found
(m, 5H), 7.39 (t, J¼7.4 Hz, 1H); 13C NMR (75 MHz, CDCl3)
d
163.9,
301.1016; FTIR (neat) cmꢁ1 2923, 2856, 1541, 1370, 1258, 1171, 1087,
1055, 1014, 907, 810, 666, 542.
157.4, 130.4, 129.9, 129.3 (2C), 129.1, 128.2 (2C), 124.0, 122.3, 120.6,
110.3; HRMS (ESI) Calcd for C13H10NO [MþH]þ 196.0762, Found
196.0755; FTIR (neat) cmꢁ1 1610, 1490, 1446, 1372, 1237, 895, 873,
746, 693, 659. All physical and spectroscopic data were in complete
agreement with the reported ones.31
4.3.3. 2-Ethyl-5-nitro-1-tosyl-benzo[d]imidazole (5c). Compound
5c was obtained as a colorless oil according to general procedure
4.3, method A. Yield¼55% (47 mg). 1H NMR (300 MHz, CDCl3)
d 8.56
(d, J¼2.2 Hz, 1H), 8.26 (d, J¼9.0 Hz, J¼2.2 Hz, 1H), 8.17 (d, J¼9.0 Hz,
1H), 7.80 (d, J¼8.5 Hz, 2H), 7.34 (d, J¼8.5 Hz, 2H), 3.19 (q, J¼7.3 Hz,
2H), 2.42 (s, 3H), 1.46 (t, J¼7.3 Hz, 3H); 13C NMR (75 MHz, CDCl3)
4.2.12. 6-Methoxy-2-phenylbenzo[d]oxazole (2k). Colorless solid.
Yield¼76% (334 mg). Mp 58e59 ꢀC; previously reported 66e69 ꢀC.26
1H NMR (500 MHz, CDCl3)
d
8.19e8.17 (m, 2H), 7.62 (d, J¼9.0 Hz,1H),
d 159.6, 146.9, 145.3, 141.9, 137.5, 134.9, 130.7 (2C), 127.1 (2C), 120.3,
7.49e7.47 (m, 3H), 7.08 (d, J¼2.0 Hz,1H), 6.94 (dd, J¼8.5 Hz, J¼2.5 Hz,
116.1, 113.8, 23.7, 21.9, 11.5; HRMS (ESI) Calcd for C16H16N3O4S
[MþH]þ 346.0862, Found 346.0859; FTIR (neat) cmꢁ1 2978, 2937,
1521,1381,1342,1274,1161,1088,1045, 992, 754, 709, 665, 581, 539.
1H), 3.84 (s, 3H); 13C NMR (125 MHz, CDCl3)
d
162.3, 158.4, 151.7,
136.0, 131.2, 129.0, 127.5, 127.3, 120.1, 112.9, 95.5, 56.0; HRMS (ESI)
Calcd for C14H12NO2 [MþH]þ 226.0868, Found 226.0862; FTIR (neat)
cmꢁ1 2923, 2842,1616,1583,1498,1437,1381,1299,1204,1115,1025,
910, 854, 812. All physical and spectroscopic data were in complete
agreement with the reported ones.26
4.3.4. 5-Chloro-2-methyl-1-tosyl-benzo[d]imidazole (5d). Compound
5d was obtained as a colorless solid according to general procedure
4.3, method A. Yield¼73% (58.5 mg). Mp 160e162 ꢀC; 1H NMR
(300 MHz, CDCl3)
d
7.94 (d, J¼8.7 Hz, 1H), 7.78 (d, J¼8.4 Hz, 2H), 7.60
4.3. General procedure for the hypervalent iodine-mediated
synthesis of benzimidazoles 5 and indazoles 6
(d, J¼2.0 Hz, 1H), 7.34e7.27 (m, 3H), 2.79 (s, 3H), 2.40 (s, 3H); 13C
NMR (75 MHz, CDCl3)
d 152.9, 146.5, 142.8, 135.2, 131.8, 130.5 (2C),
130.4, 126.9 (2C), 125.2, 119.7, 114.4, 21.8, 17.0; HRMS (ESI) Calcd for
Method A: An oven-dried vial was charged with the ortho-
aminoaryl ketones 4aed or 4iek (0.25 mmol) and a solution of NH3
7 M in MeOH (1 mL) was added. The vial was capped and the re-
action mixture was stirred at room temperature for 2 h. The solvent
was removed under reduced pressure to give a yellow solid. 1H
NMR analyses of the crude showed complete disappearance of the
starting materials and formation of the desired ortho-aminoaryl
NeH ketimines. The crude ketimine was dissolved in 0.5 mL of
MeOH and PhI(OAc)2 (0.375 mmol, 121 mg) was added to the re-
action mixture. After stirring at room temperature for 1 h, the
solvent was removed under reduced pressure and the crude was
purified by chromatography on silica gel (eluent: pentane/EtOAc).
Method B: An oven-dried vial was charged with the ortho-
aminoaryl ketones 4eeh (0.2 mmol) and a solution of NH3 7 M in
MeOH (1.5 mL) was added. The vial was capped and the reaction
mixture was stirred at 50 ꢀC for 20 h. The solvent was removed
C
15H13ClN2O2S [MþH]þ 321.0465, Found 321.0462; FTIR (neat) cmꢁ1
2922,1536,1400,1289,1261,1172,1054,1009, 900, 811, 719, 664, 541.
4.3.5. 6-Methyl-5-(methylsulfonyl)-5H-[1,3]dioxolo[4,5-f]benzimid-
azole (5e). Compound 5e was obtained as a colorless oil according
to general procedure 4.3, method B. Yield¼43% (28 mg). 1H NMR
(300 MHz, CDCl3)
d
7.78 (d, J¼8.2 Hz, 2H), 7.50 (s, 1H), 7.30 (d,
J¼8.2 Hz, 2H), 7.02 (s, 1H), 6.01 (s, 2H), 2.75 (s, 3H), 2.40 (s, 3H); 13
C
NMR (75 MHz, CDCl3) d 150.2, 146.4, 146.3, 146.1, 136.0, 135.3, 130.5
(2C), 127.4, 126.9 (2C), 101.8, 99.4, 94.9, 21.8, 16.9; HRMS (ESI) Calcd
for C16H15N2O4S [MþH]þ 331.0753, Found 331.0751; FTIR (neat)
cmꢁ1 2903, 2774, 2627, 1471, 1348, 1213, 1155, 1056, 1007, 938, 813,
679, 562.
4.3.6. 3-Methyl-1-(methylsulfonyl)-1H-[1,3]dioxolo[4,5-f]indazole
(6e). Compound 6e was obtained as a colorless solid according to