Hydrochloric Acid → Ethyl 4-(Benzo[d][1,3]dioxol-5-yl)-2-(4-methoxyphenyl)pyrrolidine-3-carboxylate

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Reaction Steps

Into a 12-L flask equipped with magnetic stirring, addition funnel, temperature probe, and nitrogen inlet was charged 0.460 kg ethyl 2-(4-methoxyphenyl)-4-(3,4-methylenedioxyphenyl)-4,5-dihydro-3H-pyrrole-3-carboxylate (1.25 mol). The reaction vessel was degassed with nitrogen. Absolute 3.7 L ethanol and 1.12 L of THF were added. 31 mg bromocresol green and 94.26 g sodium cyanoborohydride (1.5 mol) were added. A solution containing 400 mL absolute ethanol and 200 mL of 12 M HCl was then added. The reaction mixture was stirred for 30 minutes after addition was complete. After the starting material was consumed, 0.5 L of 7% aq. NaHCO3 was added. The reaction mixture was concentrated and diluted with 5 L ethyl acetate. The organic layer was washed twice with 2 L of 7% aq. NaHCO3 and once with 2.5 L of 23% aq. NaCl, the dried over 190 g MgSO4, filtered, and concentrated to give 447 g of the title compound as a thick yellow oil.

Provenance & Evidence