title: Fmoc-based synthesis of peptide thioacids for azide ligations via 2-cyanoethyl thioesters.
abstract: Rapid and efficient preparation of peptide thioacids from 2-cyanoethyl peptide thioesters has been accomplished. S-2-Cyanoethyl peptide thioesters were obtained cleanly without the need for purification from resin-bound tert-butyl peptide thioesters using 3-mercaptopropionitrile as a nucleophile. Elimination of the 2-cyanoethyl group proceeded rapidly (t(1/2) < 8 min) under mild conditions and furnished peptide thioacids up to the size of a 16-mer. Peptide thioacids could be isolated or formed in situ and reacted smoothly with electron-deficient azides yielding an amide as the ligation product.
authors.affiliation: Leibniz Institute of Molecular Pharmacology, Robert-Rössle-Str. 10, 13125 Berlin, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Raz
authors.forename: Jörg
authors.initials: J
authors.lastname: Rademann
mesh_terms: D000143:Acids / Q000737:chemistry; D001386:Azides / Q000737:chemistry*; D003486:Cyanides / Q000737:chemistry*; D004952:Esters / Q000737:chemistry*; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis*; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D000143:Acids; D001386:Azides; D003486:Cyanides; D004952:Esters; D010455:Peptides; D013438:Sulfhydryl Compounds