Formic Acid → Ethyl oxazole-4-carboxylate

Participants

Reaction Steps

To a sol. of formic acid (8.62 mL, 228 mmol) in dry THF (200 mL) was added portionwise CDI (37.05 g, 228 mmol), whereas a gas evolution occurred. The mixture was stirred for 30 min, and a sol. of ethyl isocyanoacetate (25 mL, 228 mmol) in Et3N (60.5 mL, 434 mmol) was added to the reaction mixture. The mixture was stirred at rt for 1 h, then under reflux overnight. The reaction mixture was allowed to cool to rt. Water was added, and the mixture was extracted with Et2O (3×). The combined org. extracts were dried over MgSO4, filtered and concentrated. Purification of the residue by FC (EtOAc/heptane; 1:5 →1:3→1:1) yielded the title compound (27.2 g, 84%). LC-MS: tR=0.58, ES+: 142.07.

Provenance & Evidence