9394
E. Cuevas-Yan˜ez et al. / Tetrahedron 60 (2004) 9391–9396
6.96 (d, 1H), 7.10 (d, 1H), 7.52 (s, 1H); 13C NMR (CDCl3,
50 MHz) d 14.1, 48.0, 62.3, 119.1, 129.4, 137.3, 167.3; MS
[EIC] m/z (RI%): 154 [M]C (65), 81 [MKCO2Et]C (100).
1H), 7.49 (s, 1H), 7.78 (m, 1H); 13C NMR (DMSO-d6,
50 MHz) d 58.3, 122.6, 125.9, 126.9, 129.2, 131.4, 135.3,
139.6, 139.8, 194.7; MS [FABC] m/z (RI%): 255 [MC1]C
(15); HRMS (FABC): for C11H9Cl2N2O calcd 255.0092,
found 255.0998.
2.1.2. 1-Ethoxycarbonylmethylimidazole-2-carboxylic
)
acid ethyl ester (2). Colorless oil (68%). IR (film, cmK1
1
2975, 1747, 1713; H NMR (CDCl3, 200 MHz) d 1.14 (t,
3H), 1.28 (t, 3H), 4.25 (q, 2H), 4.39 (q, 2H), 5.13 (s, 2H),
7.07 (d, 1H), 7.22 (d, 1H,); 13C NMR (CDCl3, 50 MHz) d
14.1, 14.4, 49.8, 59.2, 61.6, 115.0, 126.6, 142.7, 160.6,
167.3; MS [EIC] m/z (RI%): 226 [M]C (46), 82 [MK
C6H8O4]C (100); HRMS (FABC): for C10H15N2O4 calcd
227.1032, found 227.1039.
2.1.9. 2-Imidazol-1-yl-1-(2-iodophenyl)ethanone (9).
)
White solid (42%), mp 142–143 8C. IR (film, cmK1
1
2961, 1687; H NMR (DMSO-d6, 200 MHz) 5.56 (s,2H),
7.32 (m, 2H), 7.57 (m, 2H), 7.84 (m, 2H), 8.03 (m, 1H); 13C
NMR (DMSO-d6, 50 MHz) d 54.1, 92.6, 128.3, 128.9,
131.3, 133.0, 138.6, 138.8, 140.2, 140.7, 197.5; MS [FABC
] m/z (RI%): 313 [MC1]C (100); HRMS (FABC): for
C11H10IN2O calcd 312.9838, found 312.9841.
2.1.3. Benzoimidazol-1-yl acetic acid ethyl ester (3).
White solid (55%), mp 61–62 8C (lit. 61–63 8C).18 IR (film,
cmK1) 2977, 1743; 1H NMR (DMSO-d6, 200 MHz) d 1.21
(t, 3H), 4.17 (q, 2H), 5.25 (s, 2H), 7.25 (m, 2H), 7.6 (m, 2H),
8.21 (s, 1H); 13C NMR (DMSO-d6, 50 MHz) d 14.1, 45.8,
61.8, 110.4, 119.6, 121.6, 122.4, 143.5, 144.6, 168.5; MS
[EIC] m/z (RI%): 204 [M]C (27), 131 [MKCO2Et]C
(100).
2.2. Preparation of p-toluenesulfonylhydrazones
Typical procedure. A solution of the p-toluenesulfon-
hydrazide (4.46 g, 24 mmol) and the appropriate carbonyl
compound (20 mmol) in Me OH (50 mL) and 10% HCl
(0.1 mL) was heated at reflux for 24 h. The reaction mixture
was cooled to room temperature, the final product was
filtered and purified by crystallization.
2.1.4. 1-Imidazol-1-yl-4-phenylbutan-2-one (4). Colorless
oil (45%). IR (CHCl3, cmK1) 2966, 1738; 1H NMR
(DMSO-d6, 200 MHz) d 2.81 (s, 4H), 5.01 (s, 2H), 6.89
(s, 1H), 7.05 (s, 1H), 7.24 (m, 5H), 7.50 (s, 1H); 13C NMR
(DMSO-d6, 50 MHz) d 28.5, 54.6, 120.6, 125.9, 128.1,
128.3, 138.0, 140.8, 203.8; MS [FABC] m/z (RI%): 215
[MC1]C (100); HRMS (FABC): for C13H15N2O calcd
215.1184, found 215.1189.
2.2.1. p-Toluenesulfonylhydrazone of benzo[1,3]dioxole-
5-carbaldehyde (10). White solid (95%), mp 143–145 8C.
IR (film, cmK1) 3195, 2989, 1597, 1163; 1H NMR (CDCl3,
200 MHz) d 2.37 (s, 3H), 5.95 (s, 2H), 6.69 (m, 1H), 6.89
(m, 1H), 7.15, (m, 1H), 7.29 (d, 2H), 7.70 (s, 1H), 7.86 (d,
2H); 13C NMR (CDCl3, 50 MHz) d 21.5, 101.4, 105.6,
108.0, 123.7, 127.7, 127.8, 129.6, 135.2, 144.0, 148.0,
148.1, 149.6; MS [EIC] m/z (RI%): 318 [M]C (40), 91
[C6H4CH3]C (100); HRMS (FABC): for C15H15N2O4S
calcd 319.0753, found 319.0755.
2.1.5. 2-Imidazol-1-yl-1-phenylethanone (5). White solid
(40%), mp 118 8C (lit. 117–118 8C).19 IR (CHCl3, cmK1
)
2962, 1707; 1H NMR (DMSO-d6, 200 MHz) d 5.74 (s, 2H),
6.92 (s, 1H), 7.12 (s, 1H), 7.54 (m, 5H), 8.04 (s, 1H); 13C
NMR (DMSO-d6, 50 MHz) d 52.5, 120.8, 127.95, 128.9,
133.9, 134.4, 138.4, 193.5; MS [EIC] m/z (RI%): 186 [M]C
(22), 105 [C6H5CO]C (100).
2.2.2. p-Toluenesulfonylhydrazone of -cyclohexanone
(11). White solid (97%), mp 161–162 8C (lit. 156 8C).20
IR (CHCl3, cmK1) 3302, 2942, 1639, 1162; 1H NMR
(CDCl3, 200 MHz) d 1.57 (m, 2H),1.77 (m, 4H), 2.22 (m,
4H), 2.42 (s, 3H), 7.31 (d, 2H), 7.85 (d, 2H); 13C NMR
(CDCl3, 50 MHz) d 21.5, 25.2, 25.6, 26.6, 26.6, 35.1, 128.0,
129.4, 135.4, 143.7, 163.2; MS [FABC] m/z (RI%): 267
[MC1]C (100); HRMS (FABC): for C13H19N2O2S calcd
267.1167, found 267.1163.
2.1.6. 2-Imidazol-1-yl-1-(4-methoxyphenyl)ethanone (6).
(58%), mp 120–121 8C. IR (CHCl3, cmK1) 2968, 1697; 1H
NMR (DMSO-d6, 200 MHz) d 3.90 (s, 3H), 5.44 (s, 2H),
6.84 (d, 1H), 7.0 (d, 2H), 7.20 (d, 1H), 7.58 (s, 1H), 7.97 (d,
2H); 13C NMR (DMSO-d6, 50 MHz) d 51.7, 55.1, 113.3,
113.7, 126.7, 129.8, 163.8, 189.8; MS [FABC] m/z (RI%):
217 [MC1]C (100); HRMS (FABC): for C12H13N2O2
calcd 217.0977, found 217.0981.
2.2.3. p-Toluenesulfonylhydrazone of biphenyl-4-yl-
phenyl methanone (12). White solid (89%), mp 158–
1
160 8C. IR (CHCl3, cmK1) 3276, 2926, 1599, 1164; H
NMR (CDCl3, 200 MHz) d 2.42 (s, 3H), 7.13–7.24 (m, 2H),
7.32–7.72 (m, 14H), 7.86–7.88 (m, 2H); 13C NMR (CDCl3,
50 MHz) d 21.5, 126.8, 126.9, 127.1, 127.6, 127.7, 127.8,
127.9, 128.2, 128.3, 128.8, 128.9, 129.6, 129.8, 130.1,
131.0, 135.3, 135.5, 136.4, 139.8, 140.1, 142,5, 143.0,
144.1, 153.9, 154.0; MS [FABC] m/z (RI%): 427 [MC1]C
(100); HRMS (FABC): for C26H23N2O2S calcd 427.1480,
found 427.1469.
2.1.7. 2-Benzimidazol-1-yl-1-(4-methoxyphenyl)etha-
none (7). White solid (78%), mp 133–135 8C. IR (CHCl3,
cmK1) 2970, 1696; 1H NMR (DMSO-d6, 200 MHz) d 3.91
(s, 3H), 5.95 (s, 2H), 7.14 (d, 2H), 7.21 (m, 2H), 7.49 (m,
1H), 7.68 (m, 1H), 8.09 (d, 2H), 8.17 (s, 1H); 13C NMR
(DMSO-d6, 50 MHz) d 50.3, 55.6, 110.4, 114.1, 119.2,
121.3, 122.1, 127.3, 130.46, 134.5, 143.1, 144.9, 163.7,
191.5; MS [FABC] m/z (RI%): 267 [MC1]C (75); HRMS
(FABC): for C16H15N2O2 calcd 267.1134, found 267.1139.
2.3. Insertion of in situ generated diazoalkanes to
imidazoles
2.1.8. 1-(2,4-Dichlorophenyl)-2-imidazol-1-ylethanone
(8). White solid (46%), mp 169–170 8C. IR (CHCl3,
cmK1) 2929, 1715; 1H NMR (DMSO-d6, 200 MHz) d 5.03
(s, 2H), 6.92 (s, 1H), 7.04 (s, 1H), 7.30 (m, 1H), 7.43 (m,
Typical procedure. To a suspension of 60% NaH (0.063 g,
2.64 mmol) in THF (20 mL) was added the p-toluene-
sulfonylhydrazone (2.2 mmol). The mixture was stirred at