Synthesis of 6‐(4,5‐Dihydrofuran‐2‐yl)‐ and 6‐(Tetrahydrofuran‐2‐yl)purine Bases and Nucleosides

Abstract

A novel approach to the synthesis of purine derivatives (bases and nucleosides) bearing 4,5-dihydrofuran-2-yl and tetrahydrofuran-2-yl substituents at the 6-position as partly and fully saturated analogues of biologically active 6-hetarylpurine nucleosides is reported. Palladium-catalyzed crosscoupling reactions of 6-iodopurines with new (4,5-dihydrofuran-2-yl)zinc chloride (1) gave 6-(4,5-dihydrofuran-2-yl)-

Catalyst‐Free Intermolecular Sulfonyl/Fluoromethyl Heteroarylation of Vinyl Ethers via Visible‐Light‐Induced Charge Transfer

“…Products 4 and 18 underwent facile β‐sulfone elimination in the presence of strong bases to afford α‐heteroaryl dihydrofurans 41 and 42 in 95 % yields [15] . Catalytic hydrogenation of dihydrofuran 42 with H 2 in the presence of Pd/C gave α‐heteroaryl tetrahydrofuran 43 in 91 % yield [16] . Also, hydroboration followed by oxidation of compound 42 furnished β‐hydro alkyl heterocycle 44 in 71 % yield [17] …”

“…[15] Catalytic hydrogenation of dihydrofuran 42 with H 2 in the presence of Pd/C gave αheteroaryl tetrahydrofuran 43 in 91 % yield. [16] Also, hydroboration followed by oxidation of compound 42 furnished βhydro alkyl heterocycle 44 in 71 % yield. [17] To further probe the potential reaction pathway of this catalyst-free protocol, we have performed a series of preliminary mechanistic experiments, as shown in Figure 2.…”

Modular, Step-Efficient Palladium-Catalyzed Cross-Coupling Strategy To Access C6-Heteroaryl 2-Aminopurine Ribonucleosides

“…The 6-position of purines is a prime modification site for many of these applications . Current methods have predominantly focused on C6-arylation of adenosine ribo- and deoxyribonucleosides. − In contrast, efficient access to C6-heteroaryl guanosines, , especially protocols that utilize a cost-effective coupling partner, such as 1 , are notably limited (Scheme ). − One key structural difference between adenosine and guanosine nucleobases that has the potential to have a significant impact on the success of Pd-catalyzed cross-couplings is the presence of the N2 exocyclic amine.…”

6-(Het)aryl-7-Deazapurine Ribonucleosides as Novel Potent Cytostatic Agents

“…Some L-ribonucleosides were found 11 to exhibit weak anti-HCV effect in replicon assay, but their triphoshates did not inhibit HCV RNA polymerase. In addition, nucleoside with modified purine ring such as 2-substituted 12 and 8-substituted 13 6arylpurine ribonucleosides as well as purine ribonucleosides bearing partially or fully saturated hetaryl groups 14 do not exhibit any notable biological activities. Replacing purinering N-atoms by carbon to form deazapurine analogues has also been explored.…”