Reaction #927275

Reaction equation

prazosin hydrochloride

sodium hydroxide

→

Prazosin

Solvents

water

Conditions

Workup

1. 1
   TemperatureThe solution slowly became cloudy as it was chilled for 1 hour on ice
2. 2
   Otherprecipitation by centrifugation at 1000 g for 5 minutes
3. 3
   Otherthe pellet dried for 2 days in a vacuum desiccator
4. 4
   workup.ADDITIONcontaining phosphorus pentoxide
5. 5
   workup.DISSOLUTIONIn 5 cc of a solution of 4:1 acetonitrile and water, 46.5 mg prazosin free base and an equimolar amount of alprostadil, 43 mg, were dissolved
6. 6
   workup.ADDITIONwas added
7. 7
   Temperatureto increase the volume 50%
8. 8
   Otherwas removed azeotropically
9. 9
   OtherThe mother liquor was decanted
10. 10
    OtherThe crystals were dried in a vacuum dessicator
11. 11
    workup.ADDITIONcontaining phosphorus pentoxide

Procedure

Prazosin alprostadilate was synthesized as follows. Of prazosin hydrochloride (Sigma), (202.2 mg) were dissolved in 300 cc sterile water (Baxter). To the solution was added 481.5 μL of 1 M sodium hydroxide (Fisher). The solution slowly became cloudy as it was chilled for 1 hour on ice. The cloudy solution was transferred to conical tubes in order to hasten precipitation by centrifugation at 1000 g for 5 minutes. Pellets were consolidated and recentrifuged. The pellet was resuspended in 10 cc sterile water, and after centrifugation, the supernatant was discarded and the pellet dried for 2 days in a vacuum desiccator containing phosphorus pentoxide. In 5 cc of a solution of 4:1 acetonitrile and water, 46.5 mg prazosin free base and an equimolar amount of alprostadil, 43 mg, were dissolved by heating to 50° C. for 5 minutes. The volume was reduced by one-half under a stream of nitrogen and acetonitrile was added to increase the volume 50%. This was repeated until water was removed azeotropically and only acetonitrile remained. As the volume of acetonitrile decreased, white crystals appeared. The mother liquor was decanted and discarded. The crystals were dried in a vacuum dessicator containing phosphorus pentoxide.

Source