Ammonia → 1H-Pyrazole-1-ethanol, 5-amino-4-nitroso-

Temperatur

5 °C

To a flask having an inner volume of 25 ml and equipped with a stirring device and a thermometer were charged 2.10 g (10 mmol) of 5-amino-1-(2-hydroxyethyl)-4-nitrosopyrazole hydrochloride with a purity of 91.6% by weight synthesized in the same manner as in Example 4, 3.5 ml of water and 0.5 ml of isopropyl alcohol. Then, 1 ml (16 mmol) of 28% aqueous ammonia was gradually added dropwise to the mixture, and the resulting mixture was reacted for 30 minutes while maintaining the liquid temperature to 5° C. or lower. After completion of the reaction, precipitated crystals were collected by filtration. Then, the crystals were washed with 1 ml of cold water and 1 ml of cold isopropyl alcohol, and then dried at 40° C. under reduced pressure to obtain 1.13 g of 5-amino-1-(2-hydroxyethyl)-4-nitrosopyrazole (Isolation yield: 72.0%) as reddish orange crystal with a purity of 99.7% by weight (absolute calibration curve method by high performance liquid chromatography).

1. customTo a flask having
2. customan inner volume of 25 ml and equipped with a stirring device
3. customthe resulting mixture was reacted for 30 minutes
4. customAfter completion of the reaction
5. customprecipitated crystals
6. filtrationwere collected by filtration
7. washThen, the crystals were washed with 1 ml of cold water and 1 ml of cold isopropyl alcohol
8. customdried at 40° C. under reduced pressure

ORD-Eintrag

ord-881c035807794269a7218507ec340c97

Quelldatensatz

uspto-grants-2007_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07227032B2