(S)-1-acetyl-2-methyl-4-nitrosopiperazine → (S)-1-acetyl-4-amino-2-methylpiperazine

Temperature

55 °C

To a mixture of (S)-1-acetyl-2-methyl-4-nitrosopiperazine (350 mg) in water (2 ml) and acetic acid (0.59 ml) was added zinc powder (401 mg) as portions during the period of 2 hours at 8-13° C. (exothermic reaction) with ice-water cooling bath. After removal of the bath, the temperature was raised till 55° C. and the reaction mixture was additionally stirred at 45° C. for 2 hours. The zinc residue was filtered off and washed with methanol (10 ml) on the Celite. The combined filtrate was added into dichloromethane (40 ml) and sodium hydroxide (409 mg) in water (6 ml) below 35° C. The resulting precipitate was filtered off with Celite and the residue was washed with chloroform (50 ml). The combined filtrate was washed with water, dried over magnesium sulfate and concentrated to give (S)-1-acetyl-4-amino-2-methylpiperazine (320 mg). This product was used for next step without purification.

1. custom(exothermic reaction) with ice-water cooling bath
2. customAfter removal of the bath
3. filtrationThe zinc residue was filtered off
4. washwashed with methanol (10 ml) on the Celite
5. additionThe combined filtrate was added into dichloromethane (40 ml) and sodium hydroxide (409 mg) in water (6 ml) below 35° C
6. filtrationThe resulting precipitate was filtered off with Celite
7. washthe residue was washed with chloroform (50 ml)
8. washThe combined filtrate was washed with water
9. dry with materialdried over magnesium sulfate
10. concentrationconcentrated

ORD record

ord-046d105bd7ff4259bbfea319fca8b78d

Source dataset

uspto-grants-2001_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06291464B1