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

Temperatur

10 °C

To a flask having an inner volume of 50 ml and equipped with a stirring device, a thermometer and a reflux condenser were charged 4.59 g (30 mmol) of 3,3-dimethoxy-2-hydroxyiminopropionitrile with a purity of 94.3% by weight synthesized in the same manner as in Example 1, 2.98 g (31.5 mmol) of 2-hydroxyethylhydrazine with a purity of 80.5% by weight, 7.8 ml of methanol and 4.5 ml (54 mmol) of conc. hydrochloric acid, and the mixture was reacted at 50 to 52° C. for 3 hours. After completion of the reaction, 7 ml of water was added to the mixture and the resulting mixture was cooled up to 10° C. Then, 3.5 ml (58 mmol) of 28% by weight aqueous ammonia was gradually added dropwise to the mixture, and the mixture was stirred for 30 minutes while maintaining the liquid temperature to 5° C. or lower. The precipitated crystals were collected by filtration, and then, the crystals were washed with 2.5 ml of cold water and 2.5 ml of cold methanol, and dried under reduced pressure to obtain 3.40 g of 5-amino-1-(2-hydroxyethyl)-4-nitrosopyrazole (Isolation yield: 69.7%) as reddish orange crystals with a purity of 96.0% by weight (absolute calibration curve method by high performance liquid chromatography).

1. customTo a flask having
2. customan inner volume of 50 ml and equipped with a stirring device
3. customthe mixture was reacted at 50 to 52° C. for 3 hours
4. additionwas added to the mixture
5. temperaturewhile maintaining the liquid temperature to 5° C.
6. filtrationThe precipitated crystals were collected by filtration
7. washthe crystals were washed with 2.5 ml of cold water and 2.5 ml of cold methanol
8. customdried under reduced pressure

ORD-Eintrag

ord-b25cb60db0544c30913b8e73c22d03f6

Quelldatensatz

uspto-grants-2007_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07227032B2