Further exploration of Sonogashira coupling in the synthesis of modified 2'-deoxynucleoside derivatives

ORGN 606

Felix N Ngassa, ngassaf@gvsu.edu and Erick Lindsey, ngassaf@gvsu.edu. Department of Chemistry, Grand Valley State University, 1 Campus Drive, Allendale, MI 49401
Modified purine nucleosides, and in particular their 2'-deoxyribonucleoside analogs, continue to attract the interest of many synthetic chemists because of the wide ranging biological importance of nucleosides. In continuation of our effort towards the design of efficient synthetic methods for C-C, C-N, and C-O coupling in modified nucleosides, further studies have been done on the application of the Sonogashira coupling method for C-C bond formation in modified 2'-deoxyribonucleoside derivatives. Using simple bromo-aromatics and a variety of terminal alkynes, in optimization experiments, the versatility of Sonogashira coupling was confirmed. Optimum reaction conditions were then successfully applied in the coupling of bromo-2'-deoxynucleosides with terminal alkynes. The effects of CuI, ligands, amines, Pd-species, and solvents on the successful outcome of the coupling reactions were investigated. Results of our studies will be presented