反应详情

{2-[2-(4-Ethoxy-benzyl)-5-nitro-benzoimidazol-1-yl]-ethyl}-diethyl-amine 7a (108 mg, 0.272 mmol) was reduced to the amine 8a as outlined above and the resulting ethanolic solution charged to a small, argon purged flask fitted with a magnetic stirbar. Furan-2-carboximidothioic acid benzyl ester hydrobromide 9c (168 mg, 0.564 mmol) is added to the flask and the reaction was stirred under Ar at ambient temperature for 19.5 hours. The solution was diluted with diethyl ether (100 mL) and cooled in and ice bath resulting in the formation of a off-white precipitate that was collected on a sintered glass funnel and washed with ether. The hygroscopic solid was solubilized on the funnel in methanol and the solvent collected and evaporated to yield crude solid. The solid was partitioned between H2O and ethyl acetate and 1M sodium hydroxide solution added to adjust pH to 11. The mixture was transferred to a separatory funnel and the organic layer collected. The aqueous layer was further extracted with ethyl acetate and the combined organic layers were washed with brine (twice), dried over magnesium sulphate, filtered and concentrated to afford crude. The product was purified using silica gel column chromatography eluting with 5% 2M NH3 in methanol/95% dichloromethane to afford an off white solid 13 N-(1-(2-(diethylamino)ethyl)-2-(4-ethoxybenzyl)-1H-benzo[d]imidazol-5-yl)-furan-2-carboximidamide. Yield: 125 mg (100%) 1H NMR (DMSO) δ: 0.83 (t, 6H, J=7.1), 1.27 (t, 3H, J=6.9), 2.39-2.50 (2×m, 6H), 3.97 (q, 2H, J=6.9), 4.09 (t, 2H, J=6.8), 4.21 (s, 2H), 6.10 (br s, 2H), 6.58-6.63 (m, 1H), 6.72 (d, 1H, J=7.9), 6.86 (d, 2H, J=8.5), 6.99 (br s, 1H), 7.10 (d, 1H, J=3.1), 7.17 (d, 2H, J=8.6), 7.34 (d, 1H, J=8.6), 7.78 (s, 1H).

1. additioncharged to a small, argon purged flask
2. customfitted with a magnetic stirbar
3. temperaturecooled in and ice bath
4. customresulting in the formation of a off-white precipitate that
5. customwas collected on a sintered glass funnel
6. washwashed with ether
7. customthe solvent collected
8. customevaporated
9. customto yield crude solid
10. customThe solid was partitioned between H2O and ethyl acetate and 1M sodium hydroxide solution
11. additionadded
12. customThe mixture was transferred to a separatory funnel
13. customthe organic layer collected
14. extractionThe aqueous layer was further extracted with ethyl acetate
15. washthe combined organic layers were washed with brine (twice),
16. dry with materialdried over magnesium sulphate
17. filtrationfiltered
18. concentrationconcentrated
19. customto afford crude
20. customThe product was purified
21. washeluting with 5% 2M NH3 in methanol/95% dichloromethane