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

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Reaction Steps

Triphenylphosphine oxide (3 g) was dissolved in dichloromethane (30 mL), trifluoroacetic anhydride (3.1 g) was added under ice-cooling, and the mixture was stirred for 10 min. A solution of N-[2-(benzylthio)-3,3-dimethoxypropyl]-5-(2-methoxyethoxy)-7-nitro-1H-indole-2-carboxamide (5.0 g) and thioanisole (2.5 g) in dichloromethane (20 mL) was added dropwise to this suspension under ice-cooling. The reaction solution was allowed to warm to room temperature, and stirred for 10 min. Water was added, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over magnesium sulfate, and filtrated, and the filtrate was concentrated under reduced pressure. The obtained crude product was subjected to silica gel column chromatography (ethyl acetate:hexane=10:90-40:60), and the obtained solid was washed with ethyl acetate-hexane to give the title compound (6.8 g, yield 97%) as yellow crystals. melting point 100-101° C.

Provenance & Evidence