82
P. Gogoi, D. Konwar / Tetrahedron Letters 47 (2006) 79–82
A. Org. Lett. 2002, 4, 4713–4716; (e) Boland, N. A.; Casey,
M.; Hynes, S. J.; Matthews, J. W.; Muller-Bunz, H.;
Wilkes, P. Org. Biomol. Chem. 2004, 2, 1995–2002.
C11H14N2O2 (206.244): C, 64.06; H, 6.84; N, 13.58.
Found: C, 64.40; H, 6.84; N, 13.54; HRMS calcd for
C11H14N2O2 (M+) 206.244, found 206.267.
6. (a) Preston, P. N.; Stevens, M. F. G.; Tennant, G.
Benzimidazoles and Congeneric Tricyclic Compounds, Part
2; John Wiley & Sons: New York, 1980; (b) Cedillo-
Rivera, R.; Munoz, O. J. Med. Microbiol. 1992, 37, 221–
224; (c) Chavez, B.; Cedillo-Rivera, R.; Martiner-Palomo,
A. J. Protozool. 1992, 39, 510–515; (d) Navarrete-Vaz-
quez, G.; Cedillo, R.; Hernandez-Campos, A.; Yepez, L.;
Hernandez-Luis, F.; Valdez, J.; Morales, R.; Cortes, R.;
Hernandez, M.; Castillo, R. Bioorg. Med. Chem. Lett.
2001, 11, 187–190.
7. (a) Neef, G.; Eder, U.; Sauer, G. J. Org. Chem. 1981, 46,
2824–2826; (b) George, B.; Papadopoulos, E. P. J. Org.
Chem. 1977, 42, 441–443; (c) Fujioka, H.; Murai, K.;
Ohba, Y.; Hiramatsu, A.; Kita, Y. Tetrahedron Lett. 2005,
46, 2197–2199.
8. (a) Peddibhotla, S.; Tepe, J. J. Synthesis 2003, 1433–1440;
(b) Huh, D. H.; Ryu, H.; Kim, Y. G. Tetrahedron 2004,
60, 9857–9862; (c) Mitchell, J. M.; Finney, N. S. Tetra-
hedron Lett. 2000, 41, 8431–8434; (d) You, S.-L.; Kelly,
J. W. Org. Lett. 2004, 6, 1681–1683.
9. Paquette, L. A. In Encyclopedia of Reagents for Organic
Synthesis; John Wiley & Sons: New York, 1995; Vol. 4,
p 2796.
2-(4-Bromophenyl)imidazoline (entry 5). Solid; mp 242–
1
246 ꢀC; H NMR (DMSO-d6, 300 MHz): d 7.70–7.80 (m,
4H), 3.90 (s, 4H); 13C NMR (DMSO-d6, 75 MHz): d 47.4
(br), 96.3, 126.3, 130.4, 132.5, 165.0; FTIR (KBr): 3183
(NH), 2962 and 2944.5 (CH), 1609.94 (C@N) cmꢀ1; Anal.
Calcd for C9H9N2Br (225.088): C, 48.02; H, 4.03; N,
12.45. Found: C, 48.44; H, 4.06; N, 12.49; HRMS calcd
for C9H9N2Br (M+) 225.088, found 225.051.
2-(2,4-Dichlorophenyl)imidazoline (entry 6). Solid; mp
105–108 ꢀC; 1H NMR (CDCl3, 300 MHz): d 7.26–7.76 (m,
3H), 4.30 (br, 1H), 3.79 (s, 4H); 13C NMR (CDCl3,
75 MHz): d 50.72 (br), 127.77, 129.22, 130.41, 132.64,
133.03, 136.86, 163.02; FTIR (KBr): 3132 (NH), 2930
(CH), 1608 (C@N) cmꢀ1. Anal. Calcd for C9H8N2Cl2
(215.082): C, 50.26; H, 3.75; N, 13.02. Found: C, 50.26; H,
3.76; N, 13.02; HRMS calcd for C9H8N2Cl2 (M+) 215.082,
found 215.123.
2-(4-Nitrophenyl)imidazoline (entry 7). Solid; mp 231 ꢀC;
1H NMR (DMSO-d6, 300 MHz):
d 8.04 (d, 2H,
J = 8.5 Hz), 7.83 (d, 2H, J = 8.5 Hz), 3.59 (s, 4H); 13C
NMR (DMSO-d6, 75 MHz): d 49.80 (br), 123.56, 125.1,
128.6, 136.5, 148.5, 164.2; FTIR (KBr): 3188 (NH), 2945
(CH), 1683 (C@N) cmꢀ1. Anal. Calcd for C9H9N3O2
(191.189): C, 56.54; H, 4.74; N, 21.98. Found: C, 56.57; H,
4.74; N, 21.99; HRMS calcd for C9H9N3O2 (M+) 191.189,
found 191.172.
10. (a) Gogoi, P.; Sarma, G. K.; Konwar, D. J. Org. Chem.
2004, 69, 5153–5154; (b) Gogoi, P.; Hazarika, P.; Konwar,
D. J. Org. Chem. 2005, 70, 1935–1936.
11. Leyden, R. N.; Loonat, M. S.; Neuse, W. E.; Sher, B. H.;
Watkinson, W. J. J. Org. Chem. 1983, 48, 727–731.
12. General experimental procedure for the synthesis of
2-(4-N,N0-Dimethylaminophenyl)imidazoline (entry 8).
Solid; mp 258–260 ꢀC; 1H NMR (DMSO-d6, 300 MHz):
d 7.82 (d, 2H, J = 8.3 Hz), 6.94 (d, 2H, J = 8.3 Hz), 4.75
(s, 4H), 3.00 (s, 6H); 13C NMR (DMSO-d6, 75 MHz): d
44.66 (br), 107.45, 111.53, 126.30, 131.00, 154.54, 164.42;
FTIR (KBr): 3178 (NH), 2962 and 2918 (CH), 1615
(C@N) cmꢀ1; Anal. Calcd for C11H15N3 (189.26): C,
69.81; H, 8.00; N, 22.03. Found: C, 69.91; H, 7.96; N,
22.01; HRMS calcd for C11H15N3 (M+) 189.260, found
189.253.
imidazolines/benzimidazoles:
A solution of diamine
(1.0 mmol) and aldehyde (1.0 mmol) in water (10 ml)
was stirred at room temperature for 20 min, then potas-
sium carbonate (1.5 mmol) was added and the mixture
stirred for another 10 min. An aqueous solution of KI
(0.25 mmol) and I2 (0.06 g, 0.25 mmol) in water (5 ml) was
added, and then further I2 (0.75 mmol) was added
portionwise over 5 min, and the mixture was heated at
90 ꢀC with stirring for the stipulated time (Table 1).
Sodium thiosulfate solution (10 ml; 5%) was added and
the product was extracted with ethyl acetate (15 ml · 3).
The combined ethyl acetate layers were dried over
anhydrous sodium sulfate and concentrated under reduced
pressure to give the crude product, which was purified by
crystallization or column chromatography (silica gel)
using hexane and ethyl acetate as eluent.
1
2-(Nonyl)imidazoline (entry 15). Solid; mp 67–70 ꢀC; H
NMR (CDCl3, 300 MHz): d 3.80 (br, 1H), 3.56 (s, 4H),
0.85–2.24 (m, 19H); 13C NMR (CDCl3, 75 MHz): d 14.51,
23.06, 27.09, 29.55, 29.67, 29.75, 29.83, 29.90, 32.27, 50.22
(br), 168.45; FTIR (KBr): 3189 (NH), 2948 and 2925
(CH), 1613 (C@N) cmꢀ1; Anal. Calcd for C12H24N2
(196.335): C, 73.41; H, 12.32; N, 14.27. Found: C, 73.35;
H, 12.33; N, 14.27; HRMS calcd for C12H24N2 (M+)
196.335, found 196.324.
13. Unknown compounds or compounds for which incom-
plete physical data were reported in the literature were
characterized by FTIR, NMR (1H, 13C) and elemental
analysis. Selected data:
14. Svensson, P. H.; Kloo, L. Chem. Rev. 2003, 103, 1649–
1684.
15. Scully, F. E., Jr.; Davis, R. C. J. Org. Chem. 1978, 43,
1467–1468.
2-(3,4-Dimethoxyphenyl)imidazoline (entry 3). Solid; mp
129 ꢀC; 1H NMR (CDCl3, 300 MHz): d 6.84–7.46 (m, 3H),
3.93 (s, 3H), 3.92 (s, 3H), 3.78 (s, 4H); 13C NMR (CDCl3,
75 MHz): d 50.0 (br), 56.2, 56.3, 111.2, 111.5, 120.9, 123.4,
126.3, 148.9, 151.4, 164.5; FTIR (KBr): 3178 (NH), 2962
and 2918 (CH), 1615.3 (C@N) cmꢀ1; Anal. Calcd for
16. Oxley, P.; Short, W. F. J. Chem. Soc. 1947, 497.
17. Woodburn, H. M.; OÕGee, R. C. J. Org. Chem. 1952, 17,
1235–1244.
18. (a) Pouchert, C. J. In The Aldrich Library of NMR
Spectra, 2nd ed.; 1983; Vol. 2, (b) Dictionary of Organic
Compounds, 6th ed.; Chapman and Hall: London, 1996.