Nitrogen → 2-(3-Acetyl-pyrazol-1-ylmethyl)-oxazole-4-carboxylic acid ethyl ester

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Reaction Steps

In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a solution of 2-methanesulfonyloxymethyl-oxazole-4-carboxylic acid ethyl ester (160 mg, 0.64 mmol) and TBAB (41 mg, 0.13 mmol) in dry acetone (9.0 mL) was treated at rt with a solution of 1-(1H-pyrazol-5-yl)ethan-1-one hydrochloride (99 mg, 0.64 mmol) and K2CO3 (448 mg, 3.21 mmol) in acetone (4.0 mL). After stirring at rt for 2 days, the solvent was removed under reduced pressure. The residue was partitioned between water and EA, the two layers were separated and the aq. layer was extracted twice with EA. The combined org. extracts were dried over Na2SO4, filtered, and the solvent was removed under reduced pressure. Purification of the residue by FC (2:1 hept-EA) gave the title compound as a pale yellow oil. TLC: rf (1:2 hept-EA)=0.33. LC-MS-conditions 02: tR=0.80 min, [M+H]+=263.97.

Provenance & Evidence