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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. [ABSTRACT FROM AUTHOR]

A general and modular synthesis of substituted benzene and pyridine 2′- C-methyl- C-ribonucleosides was developed. Benzyl-protected haloaryl- C-nucleoside intermediates were prepared by the addition of bromo(het)aryllithium reagents to a protected lactone, followed by acetylation and reduction. These halogenated intermediates were further transformed by Pd-catalysed cross-couplings, aminations, or hydroxylations. The final deprotection was rather troublesome, and different procedures involving catalytic hydrogenation on Pd/C, or treatment with BCl3, were optimized for each derivative. The final C-nucleosides were also all converted into the corresponding NTPs. None of the C-nucleosides showed any activity in the HCV replicon assay, and none of the NTPs showed any significant inhibition of the HCV polymerase. [ABSTRACT FROM AUTHOR]