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Helvetica Chimica Acta Vol. 88 (2005)
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1002m, 907m, 870m. H-NMR (200 MHz, CDCl3): see Table 2; additionally, 7.36 7.07 (m, 21 arom. H); 3.01
2.81 (m, CH2CH2). 13C-NMR (75 MHz, CDCl3): see Table 2; additionally, 142.86 (3s); 142.29 (s); 130.04 (6d);
128.86 (3d); 128.41 (2d); 128.21 (6d); 128.15 (2d); 125.90 (d); 75.17 (s, Ph3C); 35.66 (t, C(2')); 30.34 (t, C(1')).
Anal. calc. for C30H26N2 (414.55): C 86.92, H 6.32, N 6.76; found: C 86.91, H 6.50, N 6.78.
4-(2-Phenylethyl)-1-(triphenylmethyl)-1H-imidazole-2-carbaldehyde (22a).
A soln. of 21a (1.244 g,
3mmol) in THF (65 ml) was cooled under Ar to 0 8, treated with 1.6m BuLi in hexane (2.25 ml, 3.6 mmol),
warmed to r.t., stirred for 1 h, cooled to 08, treated with DMF (0.7 ml, 9 mmol) in one portion, warmed to r.t.,
stirred for 2 h, and evaporated. A soln. of the residue in AcOEt (50 ml) was washed with aq. NH4Cl soln. and
brine, dried (MgSO4), and evaporated. FC (70 g, hexane/AcOEt 4 :1) of the yellow oil gave 22a (0.874 g, 66%).
White solid. Rf (hexane/AcOEt 3:1) 0.16. M.p. 164 166 8 (EtOH). IR (CHCl3): 3156w, 2851w, 1960w, 1814w,
1699s, 1682s, 1602w, 1540m, 1493s, 1447s, 1400m, 1332m, 1164m, 1154m, 1123w, 1087w, 1034w, 1002w, 941w,
906m. 1H-NMR (200 MHz, CDCl3): see Table 2; additionally, 9.14 (s, CHO); 7.34 7.04 (m, 20 arom. H); 3.05
2.86 (m, CH2CH2). 13C-NMR (75 MHz, CDCl3): see Table 2; additionally, 178.09 (d, CHO); 141.87 (s); 141.01
(4s); 129.07 (6d); 128.18 (2d); 127.84 (2d); 127.74 (3d); 127.64 (6d); 125.49 (d); 76.18 (s, Ph3C); 35.07 (t, C(2'));
29.80 (t, C(1')). Anal. calc. for C31H26N2O (442.56): C 84.13, H 5.92, N 6.33; found: C 83.98, H 6.18, N 6.35.
4-(2-Phenylethyl)-1-(triphenylmethyl)-1H-imidazole-2-methanol (23a). A soln. of 22a (631 mg, 1.42 mmol)
in THF/MeOH 1:1 (20 ml) was treated with NaBH4 (160 mg, 4.3mmol), stirred for 2 h, and evaporated. FC
(AcOEt/MeOH 96 :4) gave 23a (584 mg, 92%). White solid. Rf (AcOEt/hexane 1:1) 0.14. M.p. 179 1808
(MeOH). IR (CHCl3): 3573w, 3422w (br.), 3165w, 3064m, 2946m, 2860m, 1960w, 1909w, 1816w, 1602m, 1567w,
1494s, 1447s, 1370s, 1281m, 1162m, 1087m, 1036s, 1002m, 907m, 890m. 1H-NMR (300 MHz, CDCl3): see Table 2;
additionally, 7.35 7.07 (m, 20 arom. H); 4.12 (br. s, OH); 3 .70 (s, CH2O); 2.93 2.75 ( m, CH2CH2). 13C-NMR
(75 MHz, CDCl3): see Table 2; additionally, 142.52 (3s); 142.29 (s); 130.04 (6d); 128.88 (2d); 128.34 (9d); 128.25
(2d); 125.93( d); 74.92 (s, Ph3C); 58.83( t, CH2OH); 35.73 (t, C(2')); 30.18 (t, C(1')). Anal. calc. for C31H28N2O
(444.58): C 83.75, H 6.35, N 6.30; found: C 83.88, H 6.32, N 6.27.
4-(2-Phenylethyl)-1H-imidazole-2-methanol (24a). A soln. of 23a (532 mg, 1.20 mmol) in MeOH (20 ml)
was treated with glacial AcOH (1 ml), heated to reflux for 4 h, and evaporated. The residue was treated with
H2O (100 ml) and extracted with CHCl3 (3 Â 50 ml). The combined CHCl3 layers were extracted with 5% aq.
AcOH (3Â). The combined aq. layers were evaporated and dried i.v. Crystallisation from AcOEt gave 24a
(221 mg, 91%). Rf (AcOEt/MeOH 9 :1) 0.17. M.p. 139 1408 (AcOEt). IR (KBr): 1581m, 1495m, 1468s, 1442s,
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1387w, 1345w, 1306w, 1218m, 1122w, 1073m, 1048s, 1011m, 861m. H-NMR (300 MHz, CD3OD): see Table 2;
additionally, 7.27 7.07 (m, 5 arom. H); 4.63( s, CH2O); 2.95 2.83( m, CH2CH2). 13C-NMR (75 MHz, CDCl3):
see Table 2; additionally, 142.81 (s); 129.73(2 d); 129.70 (2d); 127.40 (d); 57.65 (t, CH2O); 35.73 (t, C(2')); 30.18
(t, C(1')). Anal. calc. for C12H14N2O (202.26): C 71.26, H 6.98, N 13.85; found: C 71.21, H 7.14, N 13.61.
4-Methyl-1-(triphenylmethyl)-1H-imidazole (21b) [22]. 13C-NMR (75 MHz, CDCl3): see Table 2; addition-
ally, 142.24 (3s); 129.42 (6d); 127.55 (9d); 74.57 (s, Ph3C); 13.49 (q, Me).
4-Methyl-1-(triphenylmethyl)-1H-imidazole-2-carbaldehyde (22b). A soln. of 21b (684 mg, 2 mmol) in
THF (25 ml) was cooled under Ar to À 58, treated with 1.6m BuLi in hexane (1.5 ml, 2.4 mmol), stirred for 1.5 h
at r.t., cooled to 08, treated with DMF (0.46 ml, 6 mmol) in one portion, and stirred for 1 h at r.t. After addition
of H2O (25 ml) and extraction with AcOEt (3 Â 75 ml), the combined org. layers were washed with brine, dried
(MgSO4), and evaporated. FC (100 g, hexane/AcOEt 3:1) gave 22b (502 mg, 71%). Pale yellow solid. Rf
(hexane/AcOEt 3:1) 0.21. M.p. 190 191 8 (AcOEt). IR (CHCl3): 3064m, 2841w, 1960w, 1816w, 1699s, 1682s,
1599w, 1545m, 1493m, 1446s, 1429s, 1402m, 1378m, 1340m, 1274m, 1154m, 1124w, 1088w, 1035w, 1016w, 1002w,
906m, 895m. 1H-NMR (300 MHz, CDCl3): see Table 2; additionally, 9.12 (s, CHO); 7.34 7.30 (m, 9 arom. H);
7.14 7.11 (m, 6 arom. H); 2.27 (d, J 0.6, Me). 13C-NMR (75 MHz, CDCl3): see Table 2; additionally, 178.74 (d,
CHO); 142.58 (3s); 129.80 (6d); 128.33 (6d); 128.42 (3d); 76.82 (s, Ph3C); 13.82 (q, Me). Anal. calc. for
C24H20N2O (352.43): C 81.79, H 5.72, N 7.95; found: C 81.77, H 5.89, N 8.03.
4-Methyl-1-(triphenylmethyl)-1H-imidazole-2-methanol (23b). A soln. of 22b (1.418 g, 4 mmol) in MeOH
(30 ml) was heated to 458, treated with NaBH4 (0.49 g, 13mmol) in three portions within 10 min and stirred for
2 h. The white solid was filtered off, washed with CHCl3, and the combined filtrate and washings were
evaporated. FC (AcOEt/MeOH 95 :5) gave 23b (1.330 g, 93%). White solid. Rf (AcOEt/MeOH 9 :1) 0.57. M.p.
232 2348 (AcOEt, dec.). IR (CHCl3): ca. 3600w, 3360w (br.), 3167m, 3065m, 3007s, 2924m, 2862m, 1960w,
1909w, 1818w, 1733w, 1597m, 1574m, 1493s, 1448s, 1370s, 1283m, 1155m, 1087m, 1039s, 1017m, 1002m, 907m,
890m. 1H-NMR (300 MHz, CDCl3): see Table 2; additionally, 7.35 7.30 (m, 9 arom. H); 7.14 7.10 (m, 6 arom.
H); 4.18 (br. s, OH); 3.64 (s, CH2O); 2.12 (br. s, Me). 13C-NMR (75 MHz, CDCl3): see Table 2; additionally,
142.26 (3s); 129.88 (6d); 128.12 (6d); 128.02 (3s); 74.74 (s, Ph3C); 58.76 (t, HOCH2); 13.46 (q, Me). Anal. calc.
for C24H22N2O (354.45): C 81.33, H 6.26, N 7.90; found: C 81.09, H 6.49, N 7.89.