反应详情

In accordance with a modified literature procedure (Pfeffer, P. E.; Silbert, L. S.; Chirinko, J. M. J. Org. Chem. 37(3), 1972, 451-458), a solution of 3,3-dimethyl-3-phenyl propionic acid (0.47 g, 2.6 mmol, from Reference Example 22) in tetrahydrofuran (4.5 mL) is cooled to −40° C. (dry ice/acetone) while stirring under a nitrogen atmosphere. Lithium diisopropylamide (Aldrich, 2.0 M solution in tetrahydrofuran/ethylbenzene/heptane, 2.9 mL, 5.8 mmol) is added dropwise via syringe, followed by 1,3-dimethyl-3,4,5,6-tetrahydro-2(1 H)-pyrimidinone (DMPU, 0.35 mL, 2.9 mmol). The reaction mixture is then allowed to warm to room temperature and to stir for 30 minutes before being re-cooled to 0° C. (ice water bath). Ethyl iodide (0.31 mL, 3.9 mmol) is then added neat via syringe and the reaction mixture is allowed to stir overnight while warming to room temperature. The reaction is quenched by the addition of 10% aqueous hydrochloric acid solution and extracted thrice with ethyl acetate. The combined extracts are washed twice with 10% aqueous hydrochloric acid solution and once with saturated sodium chloride solution, dried over anhydrous sodium sulfite, and concentrated under reduced pressure. The crude solid is recrystallized from hexanes to afford pure material as a white solid (0.16 g, 30%). MS (ES−): (M−H)=205.0

1. stirringto stir for 30 minutes
2. stirringto stir overnight
3. temperaturewhile warming to room temperature
4. customThe reaction is quenched by the addition of 10% aqueous hydrochloric acid solution
5. extractionextracted thrice with ethyl acetate
6. washThe combined extracts are washed twice with 10% aqueous hydrochloric acid solution and once with saturated sodium chloride solution
7. dry with materialdried over anhydrous sodium sulfite
8. concentrationconcentrated under reduced pressure
9. customThe crude solid is recrystallized from hexanes