反应详情

As shown in FIG. 7—step i, to a solution of 2,6-dibromopyridine (4.738 g) in dichloromethane (80 mL) was added dropwise n-butyllithium (2.5 N, 8.9 mL) at or below −65° C., followed by stirring at this temperature for 20 min. 4-Oxo-piperidine-1-carboxylic acid tert-butyl ester (compound 1030) (4.38 g) was added. After 15 min, the temperature was brought up to −30° C. and a saturated aqueous ammonium chloride solution (100 mL) was added. The organic and aqueous layers were separated, the aqueous layer extracted with dichloromethane (2×80 mL). The combined organics were evaporated to gave a residue which was triturated with hexane to give 6-bromo-4′-hydroxy-3′,4′,5′,6′-tetrahydro-2′H-[2,4′]bipyridinyl-1′-carboxylic acid tert-butyl ester (compound 1031) as a white solid (7.05 g).

1. waitAfter 15 min
2. customwas brought up to −30° C.
3. customThe organic and aqueous layers were separated
4. extractionthe aqueous layer extracted with dichloromethane (2×80 mL)
5. customThe combined organics were evaporated
6. customto gave a residue which
7. customwas triturated with hexane