Tributylphosphine → ethyl{2-(7-[(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-[(2-thienylsulfonyl)amino]-5-(trifluoromethoxy)-1H-indole-2-carboxamide (2.14 g), Lawesson's reagent (2.14 g) and tetrahydrofuran (50 mL) was stirred at 50° C. for 1.5 hr, and heated under reflux for 1.5 hr. The reaction mixture was concentrated, and the residue was washed with diisopropyl ether to give pale-yellow crystals. The obtained crystals were subjected to silica gel column chromatography, and eluted with hexane-ethyl acetate (4:1-1:2, volume ratio) to give yellow crystals. A mixture of the obtained crystals, ethyl but-2-ynoate (1.49 g), tributylphosphine (1.07 g), toluene (30 mL) and tetrahydrofuran (10 mL) was stirred at 70° C. for 5 hr. ethyl but-2-ynoate (900 mg) and tributylphosphine (1.07 g) 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 (4:1-1:3, volume ratio) to give the title compound (780 mg, yield 28%) as a brown oil.

Provenance & Evidence