Fully Automated Synthesis of DNA-Binding Py-Im Polyamides Using a Triphosgene Coupling Strategy

Abstract

The fully automated solid-phase synthetic strategy of hairpin pyrrole-imidazole polyamides is described. A key advance is the development of methodology for the application of triphosgene as a coupling agent in the automated synthesis of hairpin polyamides without racemization. This automated methodology is compatible with all the typical building blocks, enabling the facile synthesis of polyamide libraries in good yield (9-15%) and crude purity.

An investigation of targeted inhibition of transcription factor activity with pyrrole imidazole polyamide (PA) in chronic myeloid leukemia (CML) blast crisis cells

“…PA was prepared by automated solid phase synthesis using a CS336X synthesizer as previously described [10,11]. The synthesizer was programmed in the standard hardware configuration for DIC/HOBt (or HBTU/DIEA) protocols.…”

Pyrrole‐Imidazole Polyamides: Automated Solid‐Phase Synthesis

“…The key features of the procedure include: (1) the preactivation of the carboxylic acid is carried out with collidine in THF; and (2) the resulting precipitate is converted to the soluble DIEA hydrochloride salt by the addition of a DIEA/DMF solution (Fang et al, 2014). The monomer activation, coupling, and resin cleavage procedures are all optimized, allowing automated synthesis of a palette of hairpin Py-Im polyamides on a commercially available peptide synthesizer using BTC as the condensing agent for all coupling steps (Fang et al, 2015).…”

Targeting 24 bp within Telomere Repeat Sequences with Tandem Tetramer Pyrrole–Imidazole Polyamide Probes

“…In contrast, internal β-alanine can form β/β, β/Py, and β/Im pairs as a substitution for Py rings and can relax the curvature of the polyamides to allow their efficient binding . Py–Im polyamides can be synthesized easily by machine-assisted solid-phase peptide synthesis (SPPS) , and have been used for many purposes; for example, visualization of specific sequences, pull-down and identification of binding regions, inhibition of gene expression, transcriptional activation, , and detection of specific sequences on a solid substrate . To target a single site in the whole human genome, which comprises about 3 billion base pairs, a sequence of ≥16 bp must be recognized by DNA-binding molecules; therefore, many efforts have been made to extend the target base pair sequence of such DNA ligands.…”