Development of a Multikilogram Scale Synthesis of a TRPV1 Antagonist

A highly efficient, regioselective five-step synthesis of the TRPV1 antagonist 1 is described. The coupling of piperazine 7 with dichloropyrimidine 8 proceeded via a regioselective Pd-mediated amination affording product 11 in excellent yield. Conversion of the penultimate product 14 afforded 1 through formation of a magnesium ate complex and trapping with CO2.