Synthesis and Photophysical Properties of Alkynylated Pyrimidines by Site‐Selective Sonogashira Reactions of 2,4,5,6‐Tetrachloropyrimidine; First Synthesis of Tetraalkynyl‐pyrimidines

Abstract A variety of novel alkynyl‐substituted pyrimidines were prepared by the first site‐selective Sonogashira cross‐coupling reactions of 2,4,5,6‐tetrachloropyrimidine. The products, di‐, tri‐, and tetraalkynyl‐pyrimidines, exhibit fluorescence in the range of 395–470 nm. The synthesis of tetraalkynyl‐pyrimidines has not been previously reported, nor has the synthesis of chlorinated di‐ and trialkynylated pyrimidines.