1,2,3-Triazoles as leaving groups: S_NAr reactions of 2,6-bistriazolylpurines with O- and C-nucleophiles

• Dace Cīrule,
• Irina Novosjolova,
• Ērika Bizdēna and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 410–419, doi:10.3762/bjoc.17.37

• reactions at C(6) (V→VI→IV, Scheme 1) [11][14][62][63][77][78]. The main advantage of pathway B is a straightforward access to 2,6-diazidopurines V and 2,6-bistriazolylpurines VI due to excellent nucleophilic properties of the azide ion and well-established CuAAC reaction. Pathway B also avoids performing

• 2,6-bistriazolylpurines excellent substrates for SNAr reactions with O- and C-nucleophiles. Results and Discussion Synthesis of 2,6-bistriazolylpurine derivatives and their reactions with O-nucleophiles The 2,6-diazidopurine derivatives 1a and 1b as strategic starting materials and 2,6

• ) were inert in SNAr reactions with 2,6-bistriazolylpurines and their attempted reactions resulted in an unidentifiable mixture of byproducts. The following experiments were performed on 2,6-bistriazolylpurine nucleoside 2b in MeOH, EtOH and PrOH used as solvents and nucleophiles in the presence of NaH

1,2,3-Triazoles as leaving groups in S_NAr–Arbuzov reactions: synthesis of C6-phosphonated purine derivatives

• Kārlis-Ēriks Kriķis,
• Irina Novosjolova,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 193–202, doi:10.3762/bjoc.17.19

• event. The SNAr–Arbuzov reaction of 2,6-bistriazolylpurines follows the general regioselectivity pattern of the C6-position being more reactive towards substitution, which was unambiguously proved by X-ray analysis of diethyl (9-heptyl-2-(4-phenyl-1H-1,2,3-triazol-1-yl)-9H-purin-6-yl)phosphonate

• . Keywords: Arbuzov reaction; 2,6-bistriazolylpurines; nucleophilic aromatic substitution; purinylphosphonates; Introduction Acyclic nucleoside phosphonates (ANPs) are an important compound class due to their biological activity profile [1][2][3][4][5][6]. Compounds bearing a phosphonate moiety in their N9

• desired triazole derivatives were not obtained. Furthermore, the hydrolysis of the dialkyl ester groups were performed with TMSI [29][30], and phosphonic acid 10 was obtained. The latter was inert to the SNAr reaction with NaN3 at C2 (Scheme 4). SNAr–Arbuzov reaction between 2,6-bistriazolylpurines and P