Synthesis of polyfluoroalkylated bicyclic and tricyclic heterocyclic compounds

Abstract

In the presence of base, ethyl 2-hydropolyfluoroalk-2-enoates 1 are converted into polyfluoroalkylated pyrido[1,2-a]pyrimidines 3, 4 by reactions with 2-aminopyridine derivatives 2 and into polyfluoroalkylated pyrimido[2,1-b]benzothiazole 8 or thiazolo[3,2-a]pyrimidine 10, 11 derivatives using 2-aminobenzothiazole 7 or 2-amino-1,3-thiazole 9 derivatives in moderate to good yields. Under different basic conditions, polyfluoroalkenylimidazo[1,2-a]pyridine derivatives 5 or polyfluoroalkylated 1,3-thiazino[3,2-a]benzimidazol-4-one 14 are formed, respectively, from the reaction of 2-aminopyridine derivatives 2 or 2-mercaptobenzimidazole 12 with ethyl polyfluoroalk-2-enoates 1 in moderate yields.