反应详情

A mixture of 2-bromopyridine-5-carboxylic acid (J.Org.Chem., 12, 456 (1947)) (2.32 g, 11.49 mmol) and N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (3.12 g, 12.64 mmol) in dichloromethane (30 ml) was stired at room temperature for 1 hour under nitrogen. Absolute ethanol (5 ml) was added and the mixture stirred for 30 minutes and then concentrated under reduced pressure. The residue was partitioned between dichloromethane (40 ml) and 10% w/w aqueous potassium carbonate solution (40 ml). The aqueous layer was extracted with dichloromethane (25 ml) and the combined organic layers were dried (MgSO4) and concentrated under reduced pressure. Purification by flash chromatography on silica gel, eluting with dichloromethane gave 2-bromopyridine-5-carboxylic acid ethyl ester (2.18 g, 83%) as a colourless oil.

1. concentrationconcentrated under reduced pressure
2. customThe residue was partitioned between dichloromethane (40 ml) and 10% w/w aqueous potassium carbonate solution (40 ml)
3. extractionThe aqueous layer was extracted with dichloromethane (25 ml)
4. dry with materialthe combined organic layers were dried (MgSO4)
5. concentrationconcentrated under reduced pressure
6. customPurification by flash chromatography on silica gel
7. washeluting with dichloromethane