Cyclopropanecarboxaldehyde → Naltrexone Base

Participants

Reaction Steps

Into a round bottom flask was added noroxymorphone (2.19 g, 0.008 mole), cyclopropanecarboxaldehyde (1.07 g, 0.015 mole, 1.00 mL), ammonium formate (2.40 g, 0.038 mole), and isopropanol (20 mL, HPLC grade). After stirring for about 5 minutes, ruthenium (III) chloride (10 mg) was added. The mixture was stirred under nitrogen at room temperature for about 48 hours. HPLC indicated the reaction was complete. To the dark solution, distilled water (1 mL) was added and this mixture stirred for about 18 hours at room temperature. The entire mixture was evaporated under reduced pressure to a thick paste. Distilled water (10 mL) was added and the pH was adjusted to 9.4 from 7.0 using 29% NH3/H2O where a precipitate formed. The precipitate was filtered, washed with distilled water (10 mL), and dried overnight at 90° C. The dried precipitate yielded naltrexone base (2.35 g, 91% yield) as an off white solid.

Provenance & Evidence