Phosphorus oxychloride → HCID 21270453, compound

Participants

Reaction Steps

A solution of 2.25 g of ethyl 4-hydroxy-6,7-dihydrothieno[3,2-b]pyridine-3-carboxylate (see example 20) in 10 ml of phosphorous oxychloride is refluxed for 1 hour. After cooling excess reagent is distilled off under reduced pressure, the residue dissolved in 40 ml of dichloromethane and washed with 20 ml of 2N NaOH solution and 20 ml of water. After drying over magnesium sulfate, the filtrate is slurried with 500 mg of charcoal, filtered and evaporated to dryness. The residue is recrystallized from ether/pentane to yield ethyl 4-chloro-6,7-dihydrothieno[3,2-b]pyridine-3-carboxylate, mp 69°-70°.

Provenance & Evidence