Tributylphosphine → ethyl {2-[7-[methyl(2-thienylsulfonyl)amino]-5-(trifluoromethoxy)-1H-indol-2-yl]-4,5-dihydro-1,3-thiazol-5-yl}acetate

Participants

Reaction Conditions

Reaction Steps

A mixture of 7-[methyl(2-thienylsulfonyl)amino]-5-(trifluoromethoxy)-1H-indole-2-carboxamide (1.15 g), Lawesson's reagent (1.09 g) and tetrahydrofuran (20 mL) was stirred at 50° C. for 30 min. The reaction mixture was concentrated, and the residue was washed with diisopropyl ether to give pale-yellow crystals. A mixture of the obtained crystals, ethyl but-2-ynoate (710 mg), tributylphosphine (510 mg), toluene (30 mL) and tetrahydrofuran (15 mL) was stirred at 50° C. for 2 hr. ethyl but-2-ynoate (710 mg) and tributylphosphine (510 mg) were added to the mixture, and the mixture was further stirred at room temperature for 2.5 days. The reaction mixture was concentrated, and the residue was subjected to silica gel column chromatography, and eluted with hexane-ethyl acetate (4:1-3:1, volume ratio). The obtained crystals were washed with hexane to give the title compound (600 mg, yield 41%) as pale-yellow crystals. melting point 93-94° C.

Provenance & Evidence