Phosphorus oxychloride → HCID 18329980, compound

Participants

Reaction Steps

A mixture of ethyl 1,4-dihydro-4-oxo-3-propyl-5-pyridinecarboxylate (prepared from 3-oxoenanthic acid, ethyl ester as described in J. Heterocyclic Chem. 1980, 17, 359-368) (3.33 g, 15.9 mmol) and phosphorus oxychloride (50 ml) was heated at reflux for 2 h. The excess solvent was removed in vacuo and the residue was azeotroped with toluene. The residue was dissolved in dichloromethane (75 ml) and washed with saturated aqueous NaHCO3 (100 ml). The aqueous layer was further extracted with dichloromethane (2×75 ml), and the combined organic extracts were dried (Na2SO4) and evaporated in vacuo. The residue was purified by flash chromatography (silica gel, 25% EtOAc/hexane) to yield 2.84 g (78%) of the title compound as a pale yellow oil; 1H NMR (250 MHz, CDCl3) δ1.00 (3H, t, J 7.3 Hz), 1.42 (3H, t, J 7.1 Hz), 1.68 (2H, m), 2.77 (2H, m), 4.43 (2H, q, J 7.1 Hz), 8.51 (1H, s), 8.78 (1H, s); MS (ES+) m/z 228/230 [MH]+.

Provenance & Evidence