Synthesis and Biological Profiling of Benzofuro‐Fused 7‐Deazapurine Nucleosides

A series of benzofuro-fused 7-deazapurine (6H-furo[2,3-e]pyrimido[4,5-b]indole) 2'-deoxyribo- and ribonucleosides was designed and synthesized. The synthesis of key compound 10-chloro-6H-furo[2,3-e]pyrimido[4,5-b]indole was based on the Negishi cross-coupling of iodobenzofurane with zincated 4,6-dichloropyrimidine followed by azidation and photochemical cyclization. Glycosylation of the heterocycle with either Hoffer's chlorodeoxyribose or protected ribose followed by cross-coupling or substitution reactions at position 10 gave the desired two sets of final nucleosides that showed moderate to weak cytostatic activity and interesting fluorescence properties. Design and synthesis of various benzofuro-fused 7-deazapurine (6H-furo[2,3-e]pyrimido[4,5-b]indole) 2'-deoxyribo- and ribonucleosides is reported. The synthesis route comprises Negishi cross-coupling of iodobenzofurane with zincated 4,6-dichloropyrimidine followed by azidation and photochemical cyclization. Glycosylation of the heterocycle with either Hoffer's chlorodeoxyribose or protected ribose followed by cross-coupling or substitution reactions at position 10 gave the desired two sets of final nucleosides that showed moderate to weak cytostatic activity and interesting fluorescence properties.image