Sodium Thiosulfate → 3,5-diethyl 4-iodo-1H-pyrazole-3,5-dicarboxylate

HRID 2046233Notes

Reaction equation

[I:1]N1C(=O)CCC1=O.[NH:9]1[C:13]([C:14]([O:16][CH2:17][CH3:18])=[O:15])=[CH:12][C:11]([C:19]([O:21][CH2:22][CH3:23])=[O:20])=[N:10]1.[O-]S([O-])(=S)=O.[Na+].[Na+]>C(Cl)(Cl)Cl>[CH2:17]([O:16][C:14]([C:13]1[C:12]([I:1])=[C:11]([C:19]([O:21][CH2:22][CH3:23])=[O:20])[NH:10][N:9]=1)=[O:15])[CH3:18]

Participants

Conditions

Temperature: 80 °C

Procedure

N-iodosuccinimide (0.6 g, 2.59 mmol) was added to a solution of diethyl 3,5-pyrazoledicarboxylate (0.5 g, 2.35 mmol) in CHCl3 (10 mL) and the mixture was stirred at 80° C. for 24 hours. Then more of N-iodosuccinimide (0.6 g, 2.59 mmol) was added and the mixture was stirred at 100° C. for 48 hours more. Then the mixture was stirred at room temperature for 5 days. Then the mixture was treated with a saturated solution of Na2S2O3 and extracted with DCM. The organic layer was separated, dried (MgSO4), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 10/90). The desired fractions were collected and the solvents evaporated in vacuo to yield 4-iodo-1H-pyrazole-3,5-dicarboxylic acid diethyl ester (0.83 g, 90% yield).

Workup

stirringthe mixture was stirred at 100° C. for 48 hours more
stirringThen the mixture was stirred at room temperature for 5 days
extractionextracted with DCM
customThe organic layer was separated
dry with materialdried (MgSO4)
filtrationfiltered
customthe solvents evaporated in vacuo
customThe crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 10/90)
customThe desired fractions were collected
customthe solvents evaporated in vacuo

Sources & evidence

ORD record: ord-5f1c0013b8b94e13916015598f68d070
Source dataset: uspto-grants-2013_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08592422B2

Reaction notes

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