Ammonia → 5-Amino-4-nitroso-1-phenylpyrazole

Temperature

10 °C

To a flask having an inner volume of 25 ml and equipped with a stirring device, a thermometer and a reflux condenser were charged, 2.97 g (20 mmol) of 3,3-dimethoxy-2-hydroxyiminopropionitrile with a purity of 96.9% by weight synthesized in the same manner as in Example 1, 2.32 g (21 mmol) of phenylhydrazine with a purity of 98% by weight, 10 ml of methanol and 3.0 ml (36 mmol) of conc. hydrochloric acid, and the mixture was reacted at 50 to 52° C. for one hour. After completion of the reaction, 10 ml of water was added to the mixture to cool the same up to 10° C., then, 2.3 ml (37.9 mmol) of 28% by weight aqueous ammonia was gradually added dropwise to the mixture, and the resulting mixture was stirred for 30 minutes while maintaining the liquid temperature to 5° C. or lower for 30 minutes. Precipitated crystals were collected by filtration, and the crystals were washed with 5 ml of cold water and dried under reduced pressure to obtain 3.19 g of 5-amino-4-nitroso-1-phenylpyrazole (Isolation yield: 63.4%) as an ocherous solid with a purity of 74.9% 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. additiona thermometer and a reflux condenser were charged
4. customthe mixture was reacted at 50 to 52° C. for one hour
5. additionwas added to the mixture
6. temperaturewhile maintaining the liquid temperature to 5° C.
7. waitlower for 30 minutes
8. customPrecipitated crystals
9. filtrationwere collected by filtration
10. washthe crystals were washed with 5 ml of cold water
11. customdried under reduced pressure

ORD record

ord-70cf4a1d628942b7bcf86b5e3132ab3e

Source dataset

uspto-grants-2007_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07227032B2