反应详情

The compound of example 67a (16 g; 70 mmol) in dioxane (25 ml) was added drop wise at 5-10° C. to (toluene washed) 55% NaH (3.84 g; 80 mmol) suspended in dioxane (25 ml) over a period of 30 min. in an atmosphere of nitrogen. The reaction mixture was stirred at room temperature for 1 h, cooled to 0° C. and treated to a drop wise addition of ethyl 2-bromoacetate (8.9 ml; 80 58 mmol) over a period of 15-20 min. It was poured over crushed ice, and extracted with EtOAc. The EtOAc layer was washed with brine, dried (Na2SO4), concentrated and purified using flash chromatography (silica gel, 5-10% CH3CN in chloroform). Yield, 18.5 g (84.55%), oil; MS (ESI): 344 (M++Na), 322 (M++1).

1. temperaturecooled to 0° C.
2. additionIt was poured
3. customover crushed ice
4. extractionextracted with EtOAc
5. washThe EtOAc layer was washed with brine
6. dry with materialdried (Na2SO4)
7. concentrationconcentrated
8. custompurified
9. customYield