反应详情

Ethyl 2-(4-nitro-1H-benzimidazol-1-yl)octanoate (4.44 moles, 1.48 g.) was hydrogenated over 0.6 g of 5% Pd/C in 100 ml ethanol. The catalyst was filtered over celite. The solution was concentrated. The residue was dissolved in 25 ml DMF and added to a stirred mixture of 2-(2H-tetrazol-5-yl)benzoic acid (4.21 mmoles, 0.80 g), dicyclohexylcarbodiimide (4.31 mmoles, 0.89 g.), and hydroxybenzotriazole (4.44 mmoles, 0.60 g) in 50 mi DMF. The reaction was stirred for 4 hours. The solid was removed by filtration. The reaction was concentrated. The residue was dissolved in ethyl acetate, and washed with water. The pH was adjusted to 8.0 using 5N NaOH. The aqueous layer was acidified to pH 2.5 using 2N HCL, and then extracted with ethyl acetate. The organic phase was separated, washed with water, dried and concentrated. The product was purified over silica gel eluted with 2% EtOH in ethyl acetate with 1% acetic acid to yield 0.18 g of 2-[4-[2-(2H-tetrazol-5-yl)benzamido]-1H-benzimidazol-1-yl]octanoic acid. (MS)

1. filtrationThe catalyst was filtered over celite
2. concentrationThe solution was concentrated
3. dissolutionThe residue was dissolved in 25 ml DMF
4. customThe solid was removed by filtration
5. concentrationThe reaction was concentrated
6. dissolutionThe residue was dissolved in ethyl acetate
7. washwashed with water
8. extractionextracted with ethyl acetate
9. customThe organic phase was separated
10. washwashed with water
11. customdried
12. concentrationconcentrated
13. customThe product was purified over silica gel
14. washeluted with 2% EtOH in ethyl acetate with 1% acetic acid