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

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence