Scale-Up Synthesis of a TRPV1 Antagonist Featuring a Facile Thiazolo[5,4-d]pyrimidine Formation

An efficient and practical synthesis of a TRPV1 inhibitor bearing a thiazolo[5,4-d]pyrimidine core was developed. The initial synthesis was modified to facilitate acylation of 5-aminopyrimidine and subsequent thiazole formation. The synthesis features an efficient two-pot, five-step process for the construction of the thiazolo[5,4-d]pyrimidine ring. The new route is concise, chromatography-free, and amenable to large-scale preparation.