Direct Sulfenylation of the Purine C₈–H Bond with Thiophenols

Abstract

The one-step copper-mediated regioselective formation of the C8–S bond for purine derivatives with arylthiols was achieved using air as the green oxidant in the presence of 1.0 equiv of Na2CO3 and stoichiometric CuCl and 1,10-phenanthroline monohydrate. This method provides an economical, easy-to-handle, and effective method for the synthesis of 8-sulfenylpurine derivatives in moderate to excellent yields. The reaction is selective for C8 over C2 and C6. It also tolerates a free amine on the purine, and it has a wide substrate scope.

Cross-Dehydrogenative Coupling of Azoarenes with Dialkyl Disulfides

“…Notably, when the reaction temperature was raised up to 90 °C, the yield of 3a dropped to 62% (entry 11). TBAI and tetra- n -butylammonium bromide (TBAB) were used in the cross-coupling of purines . However, the reaction mixture became very complex and only a trace amount of 3a was detected by 1 H NMR when TBAI or TBAB was used in the current system (entries 12 and 13).…”

“…Based on literatures and our control experiments, the plausible mechanism is outlined in Scheme . The radical I was generated from disulfide with TBHP, and it was transformed to cation II via a SET process.…”

“…Purines adjacent to a thioether group have widespread bioactivities, such as A 3 adenosine receptor antagonist, antiviral, and anti-HIV agent (Figure b) . Recently, purines have been reported as good coupling partners with either ethers or sulfides . Early in 2010, Qu and co-workers developed a coupling reaction of purines with alkyl ethers .…”

Progress and prospects in copper-catalyzed C–H functionalization

“…Both electron-donating and electron-withdrawing . 87 Different variety of purine derivatives with substituents at the C2, C6, N7, and N9 were well tolerated in this reaction. Differently substituted 6-chloropurine derivatives also participated well in this reaction.…”

One-Step Visible Light Photoredox-Catalyzed Purine C8 Alkoxylation with Alcohol

“…30 Purine derivatives (1) were synthesized according to a previous method. 31 Analytical TLC was performed with silica gel GF254 plates, and the products were visualized by UV. The reaction products were purified by flash chromatography using Qingdao Haiyang Chemical Co. Ltd. silica gel (300−400 mesh).…”