A convenient one-pot synthesis of 2-(trifluoromethyl)-3,4,7,8-tetrahydro-2H-chromen-5(6H)-one derivatives and their further transformations

Abstract The trifluoromethyl containing heterocycles, 2-hydroxy-4-aryl-3-(thien-2-oyl)-2-(trifluoromethyl)-3,4,7,8-tetrahydro-2 H -chromen-5(6 H )-one derivatives 4 , were synthesized via a one-pot three-component reaction of aldehyde 1 with 1,3-cyclohexanedione 2 and 4,4,4-trifluoro-1-(thien-2-yl)butane-1,3-dione 3 in the presence of a catalytic amount of Et 3 N. The effect of bases and solvents on the reaction efficiency and yield was briefly investigated. Treatment of 4 with an excess amount of NH 4 OAc in ethanol afforded 2-trifluoromethyl-1 H -quinolin-5-one derivatives 5 . Refluxing of 4 with TsOH in CHCl 3 gave the corresponding dehydrated products 8 .