反应详情

To a suspension of methyl 2-oxo-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazine-7-carboxylate (1.24 g, 5.96 mmol) in THF (30 mL) at 0° C. was added borane-tetrahydro-furan complex (23.83 mL, 23.83 mmol). The reaction was warmed to room temperature and allowed to stir for 2 hours. LCMS analysis of the reaction mixture indicated consumption of starting material. The reaction was chilled to 0° C. and quenched slowly with MeOH (20 mL). The reaction mixture was concentrated in vacuo and the treated with 5% sulfuric acid in MeOH (50 mL). The solution was heated to reflux for 1 hour. The solvent was removed under reduced pressure and the resulting oil was dissolved in EtOAc (100 mL) and washed successively with saturated aqueous NaHCO3 (2×50 mL) and brine (50 mL). The combined organics were dried over anhydrous Na2SO4 and concentrated in vacuo to provide methyl 2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazine-7-carboxylate (1 g, 5.15 mmol, 86% yield) as a white solid. The product was used without purification. LCMS (+ESI) m/z=195.0 [M+H]+.

1. additionwas added borane-tetrahydro-furan complex (23.83 mL, 23.83 mmol)
2. customconsumption of starting material
3. temperatureThe reaction was chilled to 0° C.
4. customquenched slowly with MeOH (20 mL)
5. concentrationThe reaction mixture was concentrated in vacuo
6. additionthe treated with 5% sulfuric acid in MeOH (50 mL)
7. temperatureThe solution was heated
8. temperatureto reflux for 1 hour
9. customThe solvent was removed under reduced pressure
10. dissolutionthe resulting oil was dissolved in EtOAc (100 mL)
11. washwashed successively with saturated aqueous NaHCO3 (2×50 mL) and brine (50 mL)
12. dry with materialThe combined organics were dried over anhydrous Na2SO4
13. concentrationconcentrated in vacuo