Hydrochloric Acid → 5-Amino-1-(2-hydroxyethyl)-4-nitrosopyrazole hydrochloride

Temperature

77.5 °C

To a flask having an inner volume of 100 ml and equipped with a stirring device, a thermometer and a reflux condenser were charged 8.43 g (55 mmol) of 3,3-dimethoxy-2-hydroxyiminopropionitrile with a purity of 94.0% by weight synthesized in the same manner as in Example 1, 4.01 g (50 mmol) of 2-hydroxyethylhydrazine with a purity of 95% by weight, 50 ml of ethanol and 7.60 g (75 mmol) of conc. hydrochloric acid, and the mixture was reacted under reflux (76 to 79° C.) for one hour. After completion of the reaction, the reaction mixture was concentrated under reduced pressure, 20 ml of toluene and 20 ml of isopropyl alcohol were added to the concentrate, and the mixture was stirred at room temperature for one hour. Then, the solution was filtered and the filtrate was dried at 40° C. under reduced pressure to obtain 6.85 g of 5-amino-1-(2-hydroxyethyl)-4-nitrosopyrazole hydrochloride (Isolation yield: 67.4%) as yellow solid with a purity of 94.8% by weight (absolute calibration curve method by high performance liquid chromatography).

1. customTo a flask having
2. customan inner volume of 100 ml and equipped with a stirring device
3. customthe mixture was reacted
4. customAfter completion of the reaction
5. concentrationthe reaction mixture was concentrated under reduced pressure, 20 ml of toluene and 20 ml of isopropyl alcohol
6. additionwere added to the concentrate
7. filtrationThen, the solution was filtered
8. customthe filtrate was dried at 40° C. under reduced pressure

ORD record

ord-06330cc969cc422ba0e42e50740ac5d3

Source dataset

uspto-grants-2007_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07227032B2