31270-80-1

26956-43-4

31270-80-1

General procedure for the synthesis of 4-chlorofuranylpyridine from 4,5-dihydro-4-oxofuro[3,2]pyridine: cf. Example 4 Synthesis of 4-chlorofuro[3,2-c]pyridine. 4,5-Dihydro-4-oxofuro[3,2]pyridine (72.2 g, 534 mmol) was added to phosphorochloridic acid (100 mL) preheated to 120 °C with continuous stirring for 30 min. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure. Ice-cooled water was added to the residue and the pH was adjusted to basic with 8 M aqueous sodium hydroxide, followed by extraction with ethyl acetate. The organic phases were combined, washed with saturated brine and dried over anhydrous sodium sulfate. The solvent was again removed by distillation under reduced pressure and the resulting crude product was purified by silica gel column chromatography (eluent: ethyl acetate/hexane=30/70) to afford the target product 4-chlorofuranylpyridine (66.1 g, 81% yield). The product was characterized by 1H-NMR (CDCl3): δ 7.13 (1H, dd, J = 2.2, 1.0 Hz), 7.79 (1H, dd, J = 5.8, 1.0 Hz), 8.27 (1H, d, J = 2.2 Hz), 8.32 (1H, d, J = 5.8 Hz).