Wavelength-Selective Photoactivatable Protecting Groups for Thiols

Abstract

We developed and characterized efficient, remarkably water-soluble photolabile protecting groups for thiols based on 2-nitrobenzyl and (coumarin-4-yl)methyl chromophores, among them two new ones. The protecting groups allow, due to their different absorption maxima, wavelength-selective photocleavage of binary mixtures of cysteine derivatives protected at the thiol function with various photolabile protecting groups by irradiation with light. The concept was also functional with the two different S-protected cysteine residues in derivatives of the model peptide resact. Selective photolysis could be achieved for the peptides Ac(0)-Cys(1)(BCMACMOC),Cys(8)(7,8BCMCMOC)-resact and Ac(0)-Cys(1)(C4MNB),Cys(8)(BCMACMOC)-resact by irradiation with light of > or = 402 nm or > or = 436 nm wavelength, respectively, followed by irradiation at lambda > or = 325 nm.

Ethyl substituted coumarin-4-yl derivatives as photoremovable protecting groups for amino acids with improved stability for SPPS

“…caged thiols in peptide synthesis has also been reported by Hagen et al, who described an S-to-N-acyl shift after Fmoc-removal using piperidine [19]. Here we present an alternative coumarin derivative for solving the hydrolytic stability problem of the protected esters in SPPS.…”

Photoselective Delivery of Model Therapeutics from Hydrogels

“…Recently, wavelength-selective peptide protecting groups 20, 21 , caged surfaces 22, 23 and wavelength-orthogonal caged neurotransmitters 24 have been reported. Generally, photo-orthogonality is achieved by using chromophores with either distinct molar absorptivities or distinct quantum yields.…”

Protected thiol strategies in macromolecular design

“…Del Campo and co-workers have reported the orthogonal, wavelength selective deprotection of various surface-attached photocleavable groups, belonging to different species [132]. Similarly, the wavelength-selective release of thiols based on coumarinyl and 2-nitrobenzyl scaffolds has been described by Hagen and coworkers [133] Applications of the light-triggered release of thiols (and other functional groups) are mostly situated in the field of biochemistry. For example, Smith and co-workers presented the patterned release of thiol functionalities on a surface, with the aim of attaching biologically active molecules to it [134].…”