Hydrochloric Acid → ethyl 1-methyl-1H-pyrazole-4-carboxylate

HRID 2394928Notes

Reaction equation

N(OC(C)(C)C)=O.N[C:9]1[N:13]([CH3:14])[N:12]=[CH:11][C:10]=1[C:15]([O:17][CH2:18][CH3:19])=[O:16].Cl.O>CN(C=O)C>[CH3:14][N:13]1[CH:9]=[C:10]([C:15]([O:17][CH2:18][CH3:19])=[O:16])[CH:11]=[N:12]1

Participants

Conditions

Temperature: 30 °C

Procedure

To a solution of 90% t-butyl nitrite (50 mL, 0.37 mol) in 200 mL DMF was added in portions ethyl 5-amino-1-methyl-1H-pyrazole-4-carboxylate (39 g, 0.23 mol), maintaining the temperature at around 30° C. After the addition, the resulting mixture was warmed to 50° C. and stirred at that temperature for 0.5 h. The mixture was poured into 100 mL conc HCl and 40 mL water and extracted with CH2Cl2. The organic solution was washed with water, brine, dried and concentrated. Vacuum distillation of the residue gave 32.4 g of ethyl 1-methyl-1H-pyrazole-4-carboxylate as a clear liquid. b.p. 65°-80° C. at 0.1 torr.

Workup

additionAfter the addition
temperaturethe resulting mixture was warmed to 50° C.
extractionextracted with CH2Cl2
washThe organic solution was washed with water, brine
customdried
concentrationconcentrated
distillationVacuum distillation of the residue

Sources & evidence

ORD record: ord-cc6a6bb155544391be789b5de5672eb4
Source dataset: uspto-grants-1998_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05811411

Reaction notes

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