Methylhydrazine → HCID 178498595, compound

Temperature

0 °C

A diethyl ether solution (35 ml) of dimethyl acetylenedicarboxylate (5.0 g, 35 mmol) was cooled with a freezing medium (salt & ice). To this solution, a diethyl ether solution (15 ml) of methyl hydrazine (0.63 ml, 35 mmol) was added dropwise while maintaining the temperature at 0° C. or less. After completion of dropwise addition, the solution was stirred at 0° C. for one hour. The insoluble matter precipitated was obtained by filtration and washed with diethyl ether. The filter cake was heated to 130° C. for 30 minutes and cooled to room temperature. Methanol was added to the cake, which was concentrated under reduced pressure. Ethyl acetate was added to the obtained residue and the residue was concentrated under reduced pressure. Ethyl acetate was added to the residue and the insoluble matter precipitated was obtained by filtration, washed with ethyl acetate, and dried to obtain methyl 5-hydroxy-1-methyl-1H-pyrazole-3-carboxylate (3.26 g) as light yellow powder.

1. temperaturewhile maintaining the temperature at 0° C. or less
2. additionAfter completion of dropwise addition
3. customThe insoluble matter precipitated
4. customwas obtained by filtration
5. washwashed with diethyl ether
6. temperatureThe filter cake was heated to 130° C. for 30 minutes
7. temperaturecooled to room temperature
8. additionMethanol was added to the cake, which
9. concentrationwas concentrated under reduced pressure
10. additionEthyl acetate was added to the obtained residue
11. concentrationthe residue was concentrated under reduced pressure
12. additionEthyl acetate was added to the residue
13. customthe insoluble matter precipitated
14. customwas obtained by filtration
15. washwashed with ethyl acetate
16. customdried

ORD record

ord-7375d5589a5748858ce4398025b70f48

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08598162B2