反应详情

温度

145 °C

Methyl 3,4-diaminobenzoate (0.73 g, 4.42 mmol), 4-(diethylamino)benzaldehyde (3.0 g, 16.9 mmol) were dissolved in nitrobenzene (30 mL) and refluxed on a 145° C. oil bath overnight. The nitrobenzene was then removed in vacuo using a Kugelrohr apparatus (60° C., 0.1 mm Hg). The remaining oily residue was dissolved in CHCl3 and washed with water (3×50 mL). The combined organic layers were dried (Na2SO4), filtered, and concentrated. The crude oil was then purified through colurnn chromatography using a solvent system of 1% MeOH/CHCl3 to give methyl 2-(4-(N,N-diethyl)aminophenyl)benzimidazole-6-carboxylate as a yellowish solid (1.17 g, 82% yield). TLC (2.5% MeOH/CHCl3) Rf=0.26; 1H-NMR (500 MHz, CDCl3) 9.87 (s br, 1H), 8.30 (s br, 1H), 7.94 (dd, 1.5, 8.5, 1H), 7.91 (d, 8.5, 2H), 7.60 (s br, 1H), 6.72 (d, 8.5, 2H), 3.42 (q, 7.0, 4H), 1.21 (t, 7.0, 6H); IR (neat) 3508, 2063, 2920, 1712, 1611, 1504, 1434, 1360, 1307, 1269, 1205, 1157, 1082, 1008, 821, 751.

1. customThe nitrobenzene was then removed in vacuo
2. customa Kugelrohr apparatus (60° C., 0.1 mm Hg)
3. dissolutionThe remaining oily residue was dissolved in CHCl3
4. washwashed with water (3×50 mL)
5. dry with materialThe combined organic layers were dried (Na2SO4)
6. filtrationfiltered
7. concentrationconcentrated
8. customThe crude oil was then purified through colurnn chromatography