Hydrochloric Acid → ethyl 3-hydroxy-1H-pyrazole-4-carboxylate

HRID 1697459Notes

Reaction equation

[O-]CC.[Na+].C([O:7][CH:8]=[C:9]([C:15](OCC)=O)[C:10]([O:12][CH2:13][CH3:14])=[O:11])C.O.[NH2:21][NH2:22].Cl>C(O)C.O>[CH2:13]([O:12][C:10]([C:9]1[C:8](=[O:7])[NH:21][NH:22][CH:15]=1)=[O:11])[CH3:14]

Participants

Conditions

Temperature: 80 °C

Procedure

To a solution of sodium ethoxide (20.8 g, 0.31 mol) and diethyl ethoxymethylenemalonate (20 mL, 0.10 mol) in ethanol (400 mL), was added hydrazine monohydrate (10.0 mL, 0.20 mol) with cooling in an ice-cold water bath. The mixture was then heated at 80° C. for 3 h. The resulting mixture was diluted with water (200 mL) and neutralized with 10M HCl solution until pH 6. The mixture was extracted several times with chloroform. The aqueous layer was acidified to pH 2 and extracted again with chloroform. The combined organic layers were dried (Na2SO4) and concentrated to a solid which was washed with methanol and ether and dried to give the product (13.2 g, 80%) as a solid. 1H NMR (400 MHz, DMSO-d6) δ7.89 (s, 1H), 4.15 (q, 211, J=7.12 Hz), 1.23 (t, 3H, J=7.11 Hz).

Workup

temperaturewith cooling in an ice-cold water bath
extractionThe mixture was extracted several times with chloroform
extractionextracted again with chloroform
dry with materialThe combined organic layers were dried (Na2SO4)
concentrationconcentrated to a solid which
washwas washed with methanol and ether
customdried

Sources & evidence

ORD record: ord-9c6aeca92955443a8f250568a8ec23b4
Source dataset: uspto-grants-2012_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08163901B2

Reaction notes

Loading…