Hydrochloric Acid → (S)-(-)-2-Aminomethyl-1-ethylpyrrolidine

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Reaction Conditions

Reaction Steps

Bis (2-methoxyethoxy)aluminium dihydride (203.4 g, 0.70 mol, approx. 70% solution in toluene) and toluene (80 ml, dried over molecular sieves A) were added to a three-necked round-bottomed flask. The temperature in the flask was increased to 40° C. and then (S)-1-ethyl-2-pyrrolidinecarboxamide (21.0 g, 0.147 mol, 95% purity on GC) was added spoonwise during 45 min. In order to maintain the temperature at approx. 40° C., cooling was necessary during the addition. The temperature was decreased below 10° C. 55 min after completed addition. Water (500 ml) was added during 15 min and the pH was adjusted to 1 by adding 115 ml concentrated HCl and 100 ml H2O. After extraction, the phases were separated and 200 ml CH2Cl2 were added to the water phase. The pH was subsequently adjusted to 13-14 by adding NaOH (40%, 50 ml). The organic phase was separated and the water phase was extracted with further portions of CH2Cl2 (200+100 ml). The combined organic phases were dried, filtered and concentrated under vacuo to afford 24.8 g crude title product (83%) in an optical purity of >99%.

Provenance & Evidence