\documentclass{article}\pagestyle{empty}\begin{document}$ \left[\!\left[ {} \right.\right. $ \end{document}[(Dialkylamino)alkyl]amino\documentclass{article}\pagestyle{empty}\begin{document}$ \left.\left. {} \right]\!\right] $ \end{document}pyrimido[1,2‐<i>a</i>]benzimidazoles,2,3‐dihydro‐1<i>H</i>‐cyclopenta[4,5]pyrimido[1,2‐<i>a</i>]benzimidazoles, and <i>s</i>‐triazolo[1,5‐<i>a</i>]pyrimidines as potential antimalarial agents

Abstract

Abstract The structure of the product of the reaction of 2‐aminobenzimidazole with ethyl aceto‐acetate has been established by NMR spectroscopy as 2‐melhylpyrimido[1,2‐ a ]benzimidazol‐4‐ol (III). 7(and 8)‐Chloro‐2‐methylpyrimido[l,2‐ a ]benzimidazol‐4‐ol (VI and VIII, R  OH), 2‐(trifluoromethyl)pyrimido[i,2‐ a ]benzimidazol‐4‐ol (X), 2,7,8‐trimethylpyrimido[1,2‐ a ]benzimidazol‐4‐ol (XII), 2‐benzyl‐1,2,3,4‐tetrahydropyrido[4′,3′:4,5]pyrimido[1,2‐ a ]benzimidazol‐12‐ol (XIII), 1,2,3,4‐tetrahydrobenzimidazo[2,1‐ b ]quinazolin‐12‐ol (XIV), and 2,3‐dihydro‐1 H ‐cyclopenta[4,5]pyrimido[1,2‐ a ]benzimidazol‐11‐ol (XV) were prepared in a similar manner. Chlorination of III, VI and VIII, XV, and 5‐methyl‐ s ‐triazolo[1,5‐ a ]pyrimidin‐7‐ol (XXV, R  OH) with phosphorus oxychloride afforded the corresponding chloroheterocycles, which were condensed with the appropriate N,N ‐dialkylalkylenediamine or Nα,Nα ‐diethyl‐6‐methoxytoluene‐α,3‐diamine to give various 4‐ \documentclass{article}\pagestyle{empty}\begin{document}$ \left[\!\left[ {} \right.\right. $ \end{document} [(dialkylamino)alkyl]amino \documentclass{article}\pagestyle{empty}\begin{document}$ \left[\!\left[ {} \right.\right. $ \end{document} ‐2‐methylpyrimido[1,2‐ a ]benzimidazoles (Va‐e, VII, IX), 11‐ \documentclass{article}\pagestyle{empty}\begin{document}$ \left.\left. {} \right]\!\right] $ \end{document} [(dialkylamino)alkyl]amino \documentclass{article}\pagestyle{empty}\begin{document}$ \left[\!\left[ {} \right.\right. $ \end{document} ‐2,3‐dihydro‐1 H ‐cyclopenta[4,5]‐pyrimido[1,2‐ a ]benzimidazoles (XVIa and b), and 7‐ \documentclass{article}\pagestyle{empty}\begin{document}$ \left[\!\left[ {} \right.\right. $ \end{document} [(dialkylamino)alkyl]amino \documentclass{article}\pagestyle{empty}\begin{document}$ \left.\left. {} \right]\!\right] $ \end{document} ‐5‐methyl‐ s ‐triazolo[1,5‐ a ]pyrimidines (XXVb‐e). None of these compounds displayed significant antimalarial activity against Plasmodium berghei in the mouse.