Thermal condensation of imidazole with trifluoroacetaldehyde

The title condensation occurred readily at reflux (100°C) with the methyl hemiacetal of trifluoroacetaldehyde and provided 37.3% of 4(5)-(1′-hydroxy-2′,2′,2′-trifluoroethyl)imidazole as the major product, together with 8.8% of 2-(1′-hydroxy-2′,2′,2′-trifluoroethyl)imidazole, 7.2% of 2,4(5)-bis-(1′-hydroxy-2′,2′,2′-trifluoroethyl)imidazole and 0.4% of the 4,5-bis-product. (Trifluoroacetyl)imidazoles were prepared by oxidation of these condensation products. Nitration and bromination of the condensation products gave the corresponding nitro- and bromoimidazoles, respectively.