Example 31
Step 1: 3-(Ethylamino)-1-methylpyrrolidin-2-one
A solution of 3-amino-1-methylpyrrolidin-2-one (360 mg, 3.2 mmol) and acetaldehyde (0.89 mL, 15.8 mmol) was stirred at r.t. for 2 h in DCM (7.5 mL). Upon full conversion of amine as detected by LCMS (pH 10), the reaction mixture was concentrated under reduced pressure. Then the residue was redissolved in DCM (7.5 mL) and methanol (2.5 mL), at which point sodium cyanoborohydride (400 mg, 6.3 mmol) was added and the reaction mixture was stirred at room temperature for 16 h. The reaction was diluted with saturated NaHCO3 and the organics were extracted with EtOAc (3×). The combined organics were dried over MgSO4 and concentrated. The crude product was taken forward without additional purification. LCMS calculated for C7H15N2O (M+H)+: 143.1; found 143.2.
