Sulfuric Acid → Ethyl 1-methyl-2-(2-morpholinoethyl)pyrrole-3-carboxylate

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Reaction Steps

To a solution of 3.8 g of the compound obtained in Step C (14.05 mmol) in 28 mL of tetrahydrofuran there are added 58 mL of aqueous 10% sulphuric acid solution. The reaction mixture is stirred at ambient temperature for 2 hours and then diluted with a mixture of ethyl acetate and water. After separation, the organic phase is washed with brine, dried over MgSO4 and concentrated to dryness. To a solution of the residue thereby obtained in 70 mL of dichloroethane there are added a solution of 13.5 mL of morpholine (14.5 mmol) in a mixture composed of 30 mL of dichloroethane and 3.6 mL of 4N aqueous HCL solution in dioxane (14.5 mmol), and then 7.4 g of sodium triacetoxyborohydride (NaBH(OAc)3) (35.13 mmol). The reaction mixture is stirred at ambient temperature for 3 hours and then diluted with a mixture of dichloromethane and saturated aqueous NaHCO3 solution. After separation of the phases and extraction of the aqueous phase with dichloromethane, the organic phases are dried over MgSO4 and concentrated to dryness. The crude product thereby obtained is purified by chromatography over silica gel using dichloromethane and methanol as eluants. The title product is isolated in the form of an oil.

Provenance & Evidence