反应详情

To a solution of crude 3-[2-(2,4-dichloro-phenyl)-propionyl]-5-fluoro-indole-1-carboxylic acid tert-butyl ester (81 mg) in tetrahydrofuran (0.8 ml) (trifluoromethyl)-trimethylsilane (2M in tetrahydrofuran, 0.23 ml) and tetrabutylammonium difluorotriphenylsilicate (20 mg) were added at 0° C. After being stirred at rt for 3 h, trifluoroacetic acid (127 mg) was added at 0° C. and stirred overnight. No deprotection was observed, so the mixture was neutralized with aq. 2M Na2CO3 solution and extracted with EtOAc. The combined organic layers were washed with water and dried over MgSO4. After evaporation of the solvent, the residue was dissolved in CH2Cl2 (0.8 mL) and trifluoroacetic acid was added at 0° C. After being stirred for 1 h at 0° C. and at room temperature for 8 h, the reaction mixture was poured into ice water, neutralized with aq. 2M Na2CO3 solution and extracted with CH2Cl2. The organic phase was washed with water and aq. sat. NaCl solution, and dried over MgSO4. MS: silylated product still present, the crude product was dissolved in 0.5 mL tetrahydrofuran and a solution of tetrabutylammonium fluoride (1M in tetrahydrofuran) was added at 0° C. After being stirred at room temperature for 1.5 h, the reaction mixture was poured into water, and extracted with EtOAc. The combined organic layers were washed with water and aq. sat. NaCl, and dried over MgSO4. The product was purified by preparative TLC (cyclohexane/EtOAc 2:1) to give 17.9 mg of the title product as colorless oil. MS (m/e, ISP neg. ion )=404.4 [M−H+].

1. stirringstirred overnight
2. extractionextracted with EtOAc
3. washThe combined organic layers were washed with water
4. dry with materialdried over MgSO4
5. customAfter evaporation of the solvent
6. dissolutionthe residue was dissolved in CH2Cl2 (0.8 mL)
7. additiontrifluoroacetic acid was added at 0° C
8. stirringAfter being stirred for 1 h at 0° C. and at room temperature for 8 h
9. additionthe reaction mixture was poured into ice water
10. extractionextracted with CH2Cl2
11. washThe organic phase was washed with water and aq. sat. NaCl solution
12. dry with materialdried over MgSO4
13. dissolutionMS: silylated product still present, the crude product was dissolved in 0.5 mL tetrahydrofuran
14. additiona solution of tetrabutylammonium fluoride (1M in tetrahydrofuran) was added at 0° C
15. stirringAfter being stirred at room temperature for 1.5 h
16. additionthe reaction mixture was poured into water
17. extractionextracted with EtOAc
18. washThe combined organic layers were washed with water and aq. sat. NaCl
19. dry with materialdried over MgSO4
20. customThe product was purified by preparative TLC (cyclohexane/EtOAc 2:1)