Reaction #1583815

Reaction equation

4-[2-ethyl-4-(4-fluorophenyl)-1,3-thiazol-5-yl]pyridine 1-oxide

phosphoryl chloride

→

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

Conditions

Workup

1. 1
   Temperatureis heated
2. 2
   Temperatureunder reflux
3. 3
   Concentrationthe reaction mixture is concentrated under reduced pressure
4. 4
   workup.ADDITION50 ml of ice-water are added
5. 5
   OtherThe organic phase is separated off
6. 6
   Washonce more washed with 50 ml of water
7. 7
   Dryingdried over MgSO4
8. 8
   OtherThe residue is then purified by column chromatography on silica gel (cyclohexane/ethyl acetate)

Procedure

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).

Source