反应详情

N,N,N′N′-Tetramethylethylendiamine (21 g, 177 mmol) was added drop-wise at −70° C. to a solution of sec-butyllithium (110 mL, 1.4 M in cyclohexane, 154 mmol) in 180 mL tetrahydrofuran. 2-Methoxy-4-trifluoromethyl-benzoic acid (13 g, 59 mmol) in 60 mL tetrahydrofuran was added drop-wise at −70° C. over 2 hours. After complete addition stirring was continued at −70° C. for another 2 hours. Dimethyl disulfide (20 g, 207 mmol) was added at −70° C. within 10 min. Stirring was continued at −70° C. for another hour and the reaction was allowed to warm up. The reaction mixture was quenched with 150 mL water and extracted with 200 mL ethyl acetate. The aqueous phase was adjusted to pH1 by addition of 25% HCl and extracted twice with dichloromethane. The combined organic phases were dried on sodium sulfate, filtered and evaporated. The crude product was crystallized with heptane and yielded the title compound as a white solid (1.75 g, 11%), MS: m/e=265.1 [(M−H)−].

1. additionAfter complete addition
2. stirringStirring
3. waitwas continued at −70° C. for another hour
4. temperatureto warm up
5. customThe reaction mixture was quenched with 150 mL water
6. extractionextracted with 200 mL ethyl acetate
7. additionThe aqueous phase was adjusted to pH1 by addition of 25% HCl
8. extractionextracted twice with dichloromethane
9. customThe combined organic phases were dried on sodium sulfate
10. filtrationfiltered
11. customevaporated
12. customThe crude product was crystallized with heptane