Thioanisole → 2-[5-(dimethoxymethyl)-4,5-dihydro-1,3-thiazol-2-yl]-7-nitro-1H-indol-5-yl pivalate

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Reaction Steps

To a solution of triphenylphosphine oxide (14.8 g) in dichloromethane (50 mL) was added dropwise trifluoromethanesulfonic anhydride (3.0 mL) under ice-cooling, and the mixture was stirred for 30 min. A solution of 2-({[2-(benzylthio)-3,3-dimethoxypropyl]amino}carbonyl)-7-nitro-1H-indol-5-yl pivalate (9.38 g) and thioanisole (10.4 mL) in dichloromethane (100 mL) was added dropwise to this solution at −78° C., and the reaction mixture was stirred at −78° C. for 1 hr, and then at 0° C. for 1 hr. Saturated aqueous sodium hydrogencarbonate was added, and the mixture was extracted with ethyl acetate. The combined organic layer was washed with water and saturated brine, dried (MgSO4), and concentrated. The residue was purified by basic silica gel column chromatography (hexane:ethyl acetate=1:0-4:6) to give the title compound (4.32 g, yield 58%) as a pale-yellow amorphous powder. MS: 422(MH+).

Provenance & Evidence