Synthesis of 4-Alkynylpyrrolo[2,3-d]pyrimidines by Palladium-Catalyzed Cross-Coupling Reactions

Abstract The palladium-catalyzed cross-coupling reaction of methyl­ 5-amino-4-chloro- and 5-amino-4-iodo-7-methyl-2-(methylsulfanyl)-7H-pyrrolo[2,3-D]pyrimidine-6-carboxylate with various terminal alkynes has been investigated. The 4-iodo derivative was found to be a good substrate for the synthesis of various 4-alkynylpyrrolopyrimidines. A simple synthesis of 4-(indol-2-yl)pyrrolo[2,3-D]pyrimidines by the reaction of 4-iodopyrrolopyrimidine with 2-ethynyl-N-mesylaniline in the presence dichlorobis(triphenylphosphine)palladium and copper(I) iodide is described.