title: Photolabile multi-detachable p-alkoxybenzyl alcohol resin supports for peptide fragment or semi-synthesis.
abstract: Two photolabile multi-detachable alkoxybenzyl alcohol resins, 2-[4-(oxymethyl)phenoxy]propionyl-resin 4 and 4-[4-(oxymethyl)phenoxymethyl]-3-nitrobenzamidomethyl-resin 5 have been synthesized. Bpoc-peptide attached to resin 4 or 5 when treated with 50% trifluoroacetic acid provided the free, unprotected peptide, but on photolysis gave Bpoc-peptide p-hydroxybenzyl ester. Removal of the p-hydroxybenzyl ester in aqueous base or by oxidative work up gave a protected Bpoc-peptide suitable for fragment synthesis at its C-terminus. However, methylation of the ester to Bpoc-peptide p-methoxybenzyl ester followed by removal of the Bpoc-group gave a protected peptide p-methoxybenzyl ester suitable for fragment coupling at its N-terminus. The efficacies of these resins were evaluated in the syntheses of a model tetrapeptide and an octapeptide by using N alpha-Bpoc-, Fmoc- and Nps-amino acids. The use of 2-thiopyridine with pyridinium hydrochloride as a new and efficient thiolytic reagent for the deprotection of the Nps-group was studied.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids; D001592:Benzyl Alcohols / Q000138:chemical synthesis*; D001593:Benzyl Compounds / Q000138:chemical synthesis*; D010446:Peptide Fragments; D010455:Peptides; D010782:Photolysis; D012116:Resins, Plant / Q000138:chemical synthesis*; D014269:Trifluoroacetic Acid
chemical_list: D000596:Amino Acids; D001592:Benzyl Alcohols; D001593:Benzyl Compounds; D010446:Peptide Fragments; D010455:Peptides; D012116:Resins, Plant; D014269:Trifluoroacetic Acid