Water → Phthalimide

Participants

Reaction Steps

The title B tosylate (19.2 mmol) and purified potassium phthalimide (6.4 g, 34.6 mmol, 1.8 equiv.) in dimethylsulfoxide (70 ml, Burdick & Jackson) are heated at 90°-100° C. for 21/2 hours (checked by TLC Et2O-pet ether 2:1, no tosylate remaining). After cooling to room temperature, water (90 ml) is added. The mixture is poured into ice water (~350 ml) and stirred 30 minutes. The straw colored solid is harvested by filtration and washed with more water. The solid is dissolved in warm ethyl acetate (150 ml), washed with water (3×50 ml), dried (MgSO4), filtered and freed of solvent in vacuo. The remaining solid is recrystallized from isopropyl ether (~150 ml) to give corresponding phthalimide (13.8 mmol) is dissolved in distilled CH2Cl2 (24 ml) and distilled ethanol (104 ml) in an argon atmosphere. Anhydrous hydrazine (0.78 ml, 25.6 mmol) is added. The mixture is stirred at room temperature. After 8 hours an additional 0.2 ml of hydrazine is added and the mixture is stirred an additional 15 hours at room temperature. A solid is removed by filtration and washed with more CH2Cl2. The filtrate is taken to dryness in vacuo (on the pump at end). Cold 0.5N HCl solution (80 ml) is added. The acidic solution is washed with ether (2×100 ml) and then basified with solid K2CO3. The amine is extracted into CHCl3 (3×100 ml), dried (MgSO4) and freed of solvent in vacuo leaving an oil. Ether (100 ml) is added to this oil. After cooling in an ice bath, the solid is removed by filtration. The solvent is removed from the filtrate in vacuo leaving title amine. The material is used without further purification.

Provenance & Evidence