Sulfuric Acid → methyl 6-amino-2,3-dihydro-1H-benzo[d]pyrrolo[1,2-a]imidazole-5-carboxylate

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Reaction Steps

A solution of methyl 6-(2,2-dimethylpropionylamino)-2,3-dihydro-1Hbenzo[d]pyrrolo[1,2-a]imidazole-5-carboxylate (Intermediate 56, 0.61 g) and concentrated sulfuric acid (1.5 mL) in methanol (30 mL) was stirred and heated at reflux for 44 hours. After cooling, the solution was concentrated in vacuo and the residue was dissolved in water and ethyl acetate and basified with 5M sodium hydroxide solution. The aqueous phase was extracted with ethyl acetate (×8) and the combined extracts were dried (Na2SO4) and filtered. The filtrate was concentrated in vacuo and the residue was triturated with ether and filtered to give methyl 6-amino-2,3-dihydro-1H-benzo[d]pyrrolo[1,2-a]imidazole-5-carboxylate (0.296 g) as an off-white solid.

Provenance & Evidence