Hydrochloric Acid → Methanesulfonic acid 5-[6-fluoro-1-(toluene-4-sulfonyl)-2,3-dihydro-1H-indol-5-yl]-pent-4-ynyl ester

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Reaction Steps

A solution of 50 mg (0.141 mmol) of 5-[6-Fluoro-1-(toluene-4-sulfonyl)-2,3-dihydro-1H-indol-5-yl]-pent-4-yn-1-ol and 0.072 ml (0.42 mmol) diisopropyl ethylamine in 2 ml CH2Cl2 was treated at 0° C. with 0.033 ml (0.42 mmol) methanesulfonylchloride and stirred at room temperature for one hour. Addition of aqueous 0.1 M HCl, extraction with Et2O, drying of the organic layer with MgSO4, and evaporation of the solvent gave 60 mg of Methanesulfonic acid 5-[6-fluoro-1-(toluene-4-sulfonyl)-2,3-dihydro-1H-indol-5-yl]-pent-4-ynyl ester as brown oil of which 12 mg were dissolved in 0.5 ml DMF, treated with 0.043 ml (0.053 mmol) 2-(methylamino)ethanol and stirred at 80° C. during 2 hours. Evaporation of the solvent and excess 2-(methylamino)ethanol and chromatography on silica gel with EtOAc/MeOH/NEt3 10:1:0.1 gave 10 mg (82%) of 2-({5-[6-Fluoro-1-(toluene-4-sulfonyl)-2,3-dihydro-1H-indol-5-yl]-pent-4-ynyl}-methyl-amino)-ethanol as a light yellow oil, MS: 431 (MH+).

Provenance & Evidence