反应详情

Dissolve 2-methyl-2-phenyl-propionic acid (15.08, 91.2 mmol) in toluene (80 mL) and add, by dropwise addition over 5 minutes, thionyl chloride (15 mL, 206 mmol). Stir at room temperature overnight, add additional thionyl chloride (3 mL, 41.1 mmol) and heat to reflux for 1 hour. Remove excess thionyl chloride by azeotropic distillation with toluene (40 mL). Add toluene (20 mL) to the reaction mixture along with a solution of potassium carbonate (28.0 g, 203 mmol) in water (40 mL). Add, by dropwise addition, a 40% aqueous solution of dimethylamino hydrochloride (20 mL, 0.18 mol) without cooling and stir for 2 hours. Add tert-butylmethyl ether (75 mL) following by slow addition of aqueous HCl (2N, 75 mL) with vigorous stirring. Separate the organic layer and wash with aqueous HCl (2N, 75 mL), saturated sodium hydrogen carbonate (25 mL) and brine (50 mL). Dry the organic layer over (Na2SO4), filter, evaporate the filtrate in vacuo and purify by crystallization to give 2-methyl-2-phenyl-propionic acid, dimethylamide (15.35 g, 88%) as a white solid; mp 57-59° C.

1. additionadd, by dropwise addition over 5 minutes
2. temperatureheat
3. temperatureto reflux for 1 hour
4. distillationRemove excess thionyl chloride by azeotropic distillation with toluene (40 mL)
5. additionAdd, by dropwise addition
6. stirringstir for 2 hours
7. customSeparate the organic layer
8. washwash with aqueous HCl (2N, 75 mL), saturated sodium hydrogen carbonate (25 mL) and brine (50 mL)
9. dry with materialDry the organic layer over (Na2SO4)
10. filtrationfilter
11. customevaporate the filtrate in vacuo
12. custompurify by crystallization