Phosphorus oxychloride → Ethyl 4-chloro-2-methyl-5,6,7,8-tetrahydro[1]benzothieno[2,3-b]pyridine-3-carboxylate
Reaction equation
[CH2:1]([O:3][C:4]([C:6]1[C:7](O)=[C:8]2[C:15]3[CH2:16][CH2:17][CH2:18][CH2:19][C:14]=3[S:13][C:9]2=[N:10][C:11]=1[CH3:12])=[O:5])[CH3:2].P(Cl)(Cl)([Cl:23])=O>>[CH2:1]([O:3][C:4]([C:6]1[C:7]([Cl:23])=[C:8]2[C:15]3[CH2:16][CH2:17][CH2:18][CH2:19][C:14]=3[S:13][C:9]2=[N:10][C:11]=1[CH3:12])=[O:5])[CH3:2]Participants
3
Conditions
- Temperature
- 100 °C
Procedure
The ethyl(4-hydroxy-2-methyl-5,6,7,8-tetrahydro[1]benzothieno[2,3-b]pyridin-3-yl)carboxylate (2.45 g; 8.41 mmol) was suspended in phosphorus oxychloride (15.7 mL; 168.17 mmol) and the mixture was heated at 100° C. for 40 min. After cooling, the excess of phosphorus oxychloride was removed under reduced pressure, the residue was diluted in ethyl acetate and washed with a saturated solution of sodium hydrogencarbonate, brine and water. The organic layer was dried over sodium sulphate and concentrated under reduced pressure. Purification by flash-chromatography on silica gel using a gradient of ethyl acetate (0-40%) in dichloromethane furnished 1.79 g (68%) of the title compound as a dark oil.
Workup
- temperatureAfter cooling
- customthe excess of phosphorus oxychloride was removed under reduced pressure
- additionthe residue was diluted in ethyl acetate
- washwashed with a saturated solution of sodium hydrogencarbonate, brine and water
- dry with materialThe organic layer was dried over sodium sulphate
- concentrationconcentrated under reduced pressure
- customPurification by flash-chromatography on silica gel using a gradient of ethyl acetate (0-40%) in dichloromethane
Sources & evidence
- ORD record
- ord-97235b99a1dc4dcbb46346eb09af6b03
- Source dataset
- uspto-grants-2014_07
- Patent number
- US08785638B2
Reaction notes
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