反应详情

温度

128 °C

As shown in FIG. 7—step ii, compound 1031 (2.0 g) was mixed with TFA (25 mL) in a sealed tube and heated at 128° C. for 2 days. Removal of the TFA gave a residue, which was dissolved in methanol (30 mL) and treated with triethylamine (2 mL) and di-tert-butyl dicarbonate (1.4 mL). After 1 hour, the volatiles were removed in vacuo and water (100 mL) was added. Extraction with dichloromethane (3×), concentration, and purification by chromatography (SiO2, 20% ethyl acetate/hexane) gave 6-bromo-3′,6′-dihydro-2′H-[2,4′]bipyridinyl-1′-carboxylic acid, tert-butyl ester (compound 1032) (0.96 g).

1. customRemoval of the TFA
2. customgave a residue, which
3. customthe volatiles were removed in vacuo and water (100 mL)
4. additionwas added
5. extractionExtraction
6. concentrationwith dichloromethane (3×), concentration, and purification by chromatography (SiO2, 20% ethyl acetate/hexane)