Phosphorus oxychloride → 3-Bromo-7-chloro-2-methylthieno[2,3-c]pyridine

HRID 1668968Notes

Reaction equation

HRID 1668968 reaction equation
[Br:1][C:2]1[C:10]2[C:5](=[CH:6][N+:7]([O-])=[CH:8][CH:9]=2)[S:4][C:3]=1[CH3:12].P(Cl)(Cl)([Cl:15])=O>C(Cl)(Cl)Cl>[Br:1][C:2]1[C:10]2[C:5](=[C:6]([Cl:15])[N:7]=[CH:8][CH:9]=2)[S:4][C:3]=1[CH3:12]

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 673397463-bromo-2-methylthieno[2,3-c]pyridine-N-Oxide

Product 1

HCID 584664573-Bromo-7-chloro-2-methylthieno[2,3-c]pyridine

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Conditions

Temperature
70 °C

Procedure

3-Bromo-2-methylthieno[2,3-c]pyridine-N-Oxide (0.500 g, 2.05 mmol) was dissolved in chloroform (10 mL) and treated with phosphorous oxychloride (0.955 ml, 10.2 mmol). The reaction was heated to 70° C. while stirring. After 3 hours, the volatiles were removed in vacuo and the residual phosphorous oxychloride was azeotroped with toluene. The resulting residue was taken up in DCM and washed (2×) with an aqueous saturated solution of sodium bicarbonate, then with water and then brine. The organic layer was then dried with sodium sulfate and purified by column chromatography on silica gel using a gradient of 20-60% EtOAc in hexanes to give 3-bromo-7-chloro-2-methylthieno[2,3-c]pyridine as a yellow solid. MS (M+H)+ 263.

Workup

  1. customthe volatiles were removed in vacuo
  2. customthe residual phosphorous oxychloride was azeotroped with toluene
  3. washwashed (2×) with an aqueous saturated solution of sodium bicarbonate
  4. dry with materialThe organic layer was then dried with sodium sulfate
  5. custompurified by column chromatography on silica gel using a gradient of 20-60% EtOAc in hexanes

Sources & evidence

ORD record
ord-904f2d12124047e0becc5206b44233b4
Source dataset
uspto-grants-2011_08
Patent number
US07989461B2

Reaction notes

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