Semisynthesis of 3′(2′)‐O‐(Aminoacyl)‐tRNA Derivatives as Ribosomal Substrate

Abstract

AbstractAn efficient synthesis of (3′‐terminally) 3′(2′)‐O‐aminoacylated pCpA derivatives is described, which could lead to the production of (aminoacyl)‐tRNAs following T4 RNA ligase mediated ligation. The tetrahydrofuranyl (thf) group was used as a permanent protective group for the 2′‐OH of the cytidine moiety which can be removed during the purification of the 3′(2′)‐O‐aminoacylated‐pCpA. This approach allowed for a general synthesis of (3′‐terminally) 3′(2′)‐O‐aminoacylated oligonucleotides. The fully protected pCpA 14 was synthesized by phosphoramidite chemistry and treated with NH3 solution to remove the 2‐cyanoethyl and benzoyl groups (→ 15; Schemes 1 and 2). The 2′‐O‐thf‐protected‐pCpA 15 was coupled with α‐amino acid cyanomethyl esters, and the products 20a–c were deprotected and purified with AcOH buffer to afford 3′(2′)‐O‐aminoacylated pCpA 21a–c in high yields. The 3′(2′)‐O‐aminoacylated pCpA were efficiently ligated with tRNA(− CA) to yield (aminoacyl)‐tRNA which was an active substrate for the ribosome.