Ammonia → 5-(5-nitrofuran-2-yl)-1H-pyrazole-4-carbaldehyde

HRID 839205Notes

Reaction equation

[N+:1]([O-:4])(O)=[O:2].C(OC(=O)C)(=O)C.[O:12]1[CH:16]=[CH:15][CH:14]=[C:13]1[C:17]1[C:21]([CH:22]=[O:23])=[CH:20][NH:19][N:18]=1.C([O-])(=O)C.[Na+].N>S(=O)(=O)(O)O>[N+:1]([C:16]1[O:12][C:13]([C:17]2[C:21]([CH:22]=[O:23])=[CH:20][NH:19][N:18]=2)=[CH:14][CH:15]=1)([O-:4])=[O:2]

Participants

Conditions

Temperature: 30 °C

Procedure

Add 3 ml of 65% nitric acid dropwise to 11 ml of acetic anhydride at room temperature. Then add 1 drop of concentrated sulfuric acid thereto before stirring for 30 minutes and then incorporating therein 1.5 g of 3-(2-furyl)-1H-pyrazole-4-carboxaldehyde. Stir the resulting admixture for 45 minutes at room temperature before adding 4.8 g of sodium acetate. Heat for 1 hour at 30° C and then for 2 hours at 40° C. Pour the thus-produced solution on ice, neutralize it with concentrated ammonia solution and extract the neutralized solution several times with chloroform. Concentrate by evaporation in vacuum and then chromatograph over a silica gel column with chloroform/ethanol (9:1) to obtain 3-(5-nitro-2-furyl)-1H-pyrazole-4-carboxaldehyde [m.p. 187° to 187.5° C].

Workup

stirringStir the resulting admixture for 45 minutes at room temperature
waitfor 2 hours at 40° C
additionPour the thus-produced solution on ice
extractionextract the neutralized solution several times with chloroform
concentrationConcentrate by evaporation in vacuum

Sources & evidence

ORD record: ord-00633147b5aa48b2b9206a6633838fd8
Source dataset: uspto-grants-1978_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04093812

Reaction notes

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