First synthesis of unexpected functionalized trifluoromethylated 8-oxa-2,4-diazaspiro[5.5]undecanes via one-pot MCRs

Abstract

Ethyl-7,11-diaryl-9-hydroxy-1,3,5-trioxo-9-(trifluoromethyl)-8-oxa-2,4-diazaspiro[5.5]undecane-10-carboxylate derivatives (4) were synthesized from barbituric acid, aromatic aldehydes and ethyl 4,4,4-trifluoro-3-oxobutanoate via a one-pot, multi-component reaction catalyzed by Et₃N. The effect of catalyst and temperature on reaction efficiency and yield was investigated. In addition, the treatment of 4 with SOCl₂/pyridine in the solvent CH₃CN afforded the corresponding dehydrated products 5. A plausible reaction mechanism for the formation of compounds 4 was presented.