反应详情

To a stirred suspension of the above acid ((6), 7.0 g, 31 mMol) in toluene (25 mL) was added oxalylchloride (5 mL) followed by one drop of dry DMF. After stirring for 16 h (the solution became clear after ~30 minutes) the reaction was evaporated to dryness and re-evaporated from fresh toluene (2×100 mL). To the resulting acid chloride in CHCl3 (10 mL) with stirring at 0° C. was added t-BuOH (1 mL) followed by pyridine (0.6 mL). The reaction was allowed to warm to room temperature and stirred for 6 h. The resulting reaction was stripped of solvent, taken up in ethyl acetate, washed with aq. 1N NaHCO3, brine, dried (MgSO4) and evaporated under reduced pressure. Purification by flash chromatography on silica gel eluted with 10% ethyl acetate in hexane gave product (7) (7.28 g, 83%) as a clear oil.

1. waitbecame clear after ~30 minutes
2. custom) the reaction was evaporated to dryness
3. customre-evaporated from fresh toluene (2×100 mL)
4. stirringTo the resulting acid chloride in CHCl3 (10 mL) with stirring at 0° C.
5. additionwas added t-BuOH (1 mL)
6. stirringstirred for 6 h
7. customThe resulting reaction
8. washwashed with aq. 1N NaHCO3, brine
9. dry with materialdried (MgSO4)
10. customevaporated under reduced pressure
11. customPurification by flash chromatography on silica gel
12. washeluted with 10% ethyl acetate in hexane