Phosphorus oxychloride → Ethyl 3-methyl-7-chlorothieno[3,2-b)pyridine-6-carboxylate

HRID 2107615Notes

Reaction equation

HRID 2107615 reaction equation
[CH3:1][C:2]1[C:6]2[NH:7][CH:8]=[C:9]([C:12]([O:14][CH2:15][CH3:16])=[O:13])[C:10](=O)[C:5]=2[S:4][CH:3]=1.P(Cl)(Cl)([Cl:19])=O>>[CH3:1][C:2]1[C:6]2=[N:7][CH:8]=[C:9]([C:12]([O:14][CH2:15][CH3:16])=[O:13])[C:10]([Cl:19])=[C:5]2[S:4][CH:3]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 225743463-methyl-6-ethoxycarbonylthieno[3,2-b]pyridin-7(4H)-one

Product 1

HCID 23046143Ethyl 3-methyl-7-chlorothieno[3,2-b)pyridine-6-carboxylate

Procedure

3-Methyl-6-ethoxycarbonylthieno[3,2-b]pyridin-7(4H)-one (7.0 g, 0.0295 mol) and phosphorus oxychloride (35 ml) were heated under reflux for 2 hours. The excess phosphorus oxychloride was removed by distillation under reduced pressure. The residue was poured onto ice, basified with 2N.NaOH and extracted with chloroform (3×100 ml). The combined chloroform extracts were washed with water, dried and evaporated to dryness to give a buff-coloured solid. This was collected, washed with petroleum ether (b.p. 40°-60°) and dried to give ethyl 3-methyl-7-chlorothieno[3,2-b]pyridine-6-carboxylate, 6.8 g, m.p. 113°-115°.

Workup

  1. temperatureunder reflux for 2 hours
  2. customThe excess phosphorus oxychloride was removed by distillation under reduced pressure
  3. additionThe residue was poured onto ice
  4. extractionNaOH and extracted with chloroform (3×100 ml)
  5. washThe combined chloroform extracts were washed with water
  6. customdried
  7. customevaporated to dryness
  8. customto give a buff-coloured solid
  9. customThis was collected
  10. washwashed with petroleum ether (b.p. 40°-60°)
  11. customdried

Sources & evidence

ORD record
ord-e32a06eb2051456d839427ee482976cf
Source dataset
uspto-grants-1990_06
Patent number
US04935431

Reaction notes

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