Phosphorus oxychloride → 2-Chloro-4-[2-ethyl-4-(4-fluorophenyl)-1,3-thiazol-5-yl]pyridine

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Reaction Steps

A mixture of 1.90 g (6.33 mmol) of 4-[2-ethyl-4-(4-fluorophenyl)-1,3-thiazol-5-yl]pyridine 1-oxide and 40 ml of phosphoryl chloride is heated under reflux. After 8 h, the reaction mixture is concentrated under reduced pressure, the residue is taken up in 150 ml of dichloromethane and 50 ml of ice-water are added. The organic phase is separated off and once more washed with 50 ml of water, dried over MgSO4 and freed from the solvent under reduced pressure. The residue is then purified by column chromatography on silica gel (cyclohexane/ethyl acetate). This gives 1.35 g (65%) of the desired product; 1H-NMR(DMSO-d6) δ: 8.35 (d, 1H), 7.49 (m, 2H), 7.35 (s, 1H), 7.25 (d, 1H), 7.19 (m, 2H), 3.06 (q, 2H), 1.37 (t, 3H).

Provenance & Evidence