SCAL linker

Synthesis of the Peptide-Thioester 8 Incorporating the SCAL Linker ... 

A concept with attractive perspectives for increased flexibility in the choice of mutually compatible reaction conditions is termed safety catch. Here, particularly robust linkers are in their stable state during synthesis and are labilized by chemical transformation immediately prior to the final cleavage of the substrates. The SCAL linker [20] becomes acid labile only... 

Scheme 16.9 Safety-catch acid labile (SCAL) linker by Patek and Lebl.

SCAL, safety catch acid-labile linker or safety catch amide linker. 

Fmoc-based solid-phase glycopeptide synthesis is compatible with the standard linkers (handles) widely used in peptide synthesis, such as Rink amide, Wang, SASRIN (mild acid cleavage), 2-chlorotrityl chloride (protected peptide acid), and Sieber (protected peptide amides). For combinatorial one-bead one-compound studies, both the safety-catch amide linker (SCAL, stable to both acid and base until sulfone reduction) [24] and the photocleavable linker 4-[4-(l-aminoethyl)-2-methoxy-5-nitrophenoxy] butyric acid [25 ] have been successfully applied. These linkers are suitable for displaying the frilly deprotected glycopeptides on bead while allowing their nondestructive recovery after bead assay. Concerning... 

---