Convenient substitution of hydroxypyridines with trifluoroacetaldehyde ethyl hemiacetal

Thermal substitution of 4-hydroxypyridine 1 with trifluoroacetaldehyde ethyl hemiacetal (TFAE) leads to a moderate yield of 3-(1-hydroxy-2,2,2-trifluoroethyl)-4-hydroxypyridine 7 in the presence of a catalytic amount of anhydrous potassium carbonate. Under similar conditions, several α-trifluoromethyl hydroxy-pyridinemethanols 8–15 are easily prepared from 2- or 3-hydroxypyridines 2–6.