Pyridine → Ethyl 2-(chloromethyl)-1H-benzo[D]imidazole-7-carboxylate

To a solution of ethyl 2,3-diaminobenzoate (4.72 g) and pyridine (2.49 g) in dichloroethane (50 ml) was added chloroacetyl chloride (3.11 g) in chloroform (10 ml) at −70° C. and the reaction mixture was stood overnight. After the reaction mixture was concentrated in vacuo, the residue was diluted with ethanol (50 ml). To the solution was added p-toluenesulfonic acid (249 mg) and the reaction mixture was refluxed for 2 hours. After the reaction mixture was concentrated in vacuo, the residue was diluted with ethyl acetate and satureated sodium hydrogen carbonate aqueous solution. The organic layer was separated and washed with brine. The solution was dried over magnesium sulfate and concentrated in vacuo. The residue was purified by silica gel column chromatography (n-hexane:ethyl acetate 4:1) to give ethyl 2-chloromethyl-1H-benzimidazole-4-carboxylate (2.98 g).

1. concentrationAfter the reaction mixture was concentrated in vacuo
2. additionthe residue was diluted with ethanol (50 ml)
3. additionTo the solution was added p-toluenesulfonic acid (249 mg)
4. temperaturethe reaction mixture was refluxed for 2 hours
5. concentrationAfter the reaction mixture was concentrated in vacuo
6. additionthe residue was diluted with ethyl acetate
7. customThe organic layer was separated
8. washwashed with brine
9. dry with materialThe solution was dried over magnesium sulfate
10. concentrationconcentrated in vacuo
11. customThe residue was purified by silica gel column chromatography (n-hexane:ethyl acetate 4:1)

ORD record

ord-8daf1803ea9a4f8481c19397695b5dde

Source dataset

uspto-grants-2001_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06207693B1