Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications.

(1H-Benzo[d][1,2,3]triazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), 1H-benzo[d][1,2,3]triazol-1-yl 4-methylbenzenesulfonate (Bt-OTs), and 3H-[1,2,3]triazolo[4,5-b]pyridine-3-yl 4-methylbenzenesulfonate (At-OTs) are classically utilized in peptide synthesis for amide-bond formation. However, a previously undescribed reaction of these compounds with alcohols in the presence of a base, leads to 1-alkoxy-1H-benzo- (Bt-OR) and 7-azabenzotriazoles (At-OR). Although BOP undergoes reactions with alcohols to furnish 1-alkoxy-1H-benzotriazoles, Bt-OTs proved to be superior.

Purinyl N1-directed aromatic C-H oxidation in 6-arylpurines and 6-arylpurine nucleosides.

Palladium-catalyzed C-H bond activation and oxidation of C6 arylpurines as well as C6 arylpurine nucleosides can be accomplished using Pd(OAc)2/PhI(OAc)2 in CH3CN. Despite the presence of four nitrogen atoms in the purine moiety as well as the polyoxygenated saccharide and a labile glycosidic bond in the nucleosides, these reactions can be effectively conducted. Notably, the generally more labile 2'-deoxyribonucleosides also undergo reaction.

Direct arylation of 6-phenylpurine and 6-arylpurine nucleosides by ruthenium-catalyzed C-H bond activation.

[Image: see text] The title reaction predominantly gives monoarylation products with various amounts of diarylation product being observed in almost all cases (see scheme). Aryl iodides as well as aryl bromides were reactive under the optimized reaction conditions. The multiple nitrogen atoms in the purine, and oxygen atoms in the saccharide posed no problems in these transformations.