Trifluoromethyl β-Enamino Diketones as Dual Substrates for the Synthesis of 5-Benzoyl-6-(trifluoromethyl)pyrimidines and their Pyrimidin-4(3H)-one Analogues

A regio- and chemoselective method for the preparation of 6-trifluoromethyl-5-benzoyl-2-methylsulfanyl pyrimidines and their pyrimidin-4(3H)-one analogues, from the cyclocondensation reaction of trifluoromethyl beta-enamino diketones with non-symmetric 2-methylisothiourea sulfates is reported. These diketones functioned as dual substrates by providing both products with high regioselectivity (onlyN(3)-substituted isomer was observed) and high chemoselectivity. A new feature provided by the starting material proposed herein is the possibility to either maintain or eliminate the trifluoromethyl group, by choosing the solvent.