Solid-phase catch, activate, and release synthesis of cyanine dyes.

[reaction: see text] Trimethine cyanine dye was synthesized by capture and activation of a hemicyanine intermediate on sulfonyl chloride resin followed by reaction and concomitant cleavage by a heterocyclic carbon nucleophile. A small array of dyes were synthesized and characterized to demonstrate the versatility of this chemistry for a number of hemicyanines and heterocyclic nucleophiles.

Solid-phase methods for the synthesis of cyanine dyes.

We report here a series of studies that explore solid-phase methodologies for the synthesis of various cyanine dyes. The scope of the previously reported catch-and-release method using sulfonyl chloride resin(1) has now been extended to include pentamethine and water-soluble cyanine dyes. We also report a new and chemically distinct synthetic strategy, employing the stepwise attack of heterocyclic carbon nucleophiles on immobilized polyene-chain precursors, allowing the clean synthesis of hydrophobic and hydrophilic trimethine and pentamethine dyes from more easily obtained starting materials. Overall, both approaches appear to be robust and versatile strategies to delivering a wide range of cyanine-based dyes in high purity.

G-quadruplex-specific peptide-hemicyanine ligands by partial combinatorial selection.

G-quadruplex DNA-specific ligands were generated using a combinatorial selection of tetrapeptides which were then conjugated to a hemicyanine scaffold. The heterocycle enhanced peptide binding affinity by approximately 1000-fold to give ligands with near micromolar affinity and >40-fold discrimination for quadruplex DNA over duplex.