Synthesis and Application of D‐ and 13C‐Labelled tert‐Butyl Hoechst Dye

ABSTRACT Herein, the successful syntheses of D3‐ and 13C‐N‐methyl and D9‐tert‐butyl Hoechst dyes are presented. This includes the preparation of the labelled D3‐ and 13C‐N‐methyl piperazines and D9‐tert‐butylated hydroxytoluene precursors. The tert‐butyl Hoechst dye is known to bind a specific RNA aptamer. Spectroscopic NMR studies of the labelled Hoechst dye‐aptamer complexes allowed for the unambiguous assignment of chemical shifts, as well as the dynamics of the bound dye. The tert‐butyl Hoechst dye binds a specific RNA aptamer, and NMR studies of labelled Hoechst dye–aptamer complexes may enable chemical shift assignments and studying the dynamics of the bound dye. Here, we present the synthesis of labelled D3‐ and 13C‐N‐methyl and D9‐tert‐butyl Hoechst dyes, along with preliminary NMR studies.