title: Activation of diketopiperazine formation by alkylammonium carboxylate salts and aprotic dipolar protophobic solvents.
abstract: Diketopiperazine formation from the N-terminal residues of a peptide chain is accelerated by aprotic dipolar protophobic solvents and catalyzed in organic solvents by alkylammonium carboxylate salts. The t1/2 for the first-order reaction of H-Ala-Pro-NH2 x TFA falls from 20 d in methanol to 3.6 min in acetonitrile containing 0.02 mol dm(-3) triethylammonium acetate; for H-Ala-Ala-NH2 x TFA in the same reaction media t1/2 falls from an unmeasurably long time to 1.3 d.
authors.affiliation: Centro di Studio di Biocristallografia, C.N.R., Napoli, Italy. capasso@chemna.dichi.unina.it
authors.forename: S
authors.initials: S
authors.lastname: Capasso
authors.forename: L
authors.initials: L
authors.lastname: Mazzarella
mesh_terms: D054659:Diketopiperazines; D004151:Dipeptides / Q000737:chemistry; D005463:Fluoroacetates; D007700:Kinetics; D010455:Peptides / Q000737:chemistry; D010879:Piperazines / Q000138:chemical synthesis*; D000644:Quaternary Ammonium Compounds; D012492:Salts; D012997:Solvents; D014269:Trifluoroacetic Acid / Q000737:chemistry
chemical_list: D054659:Diketopiperazines; D004151:Dipeptides; D005463:Fluoroacetates; D010455:Peptides; D010879:Piperazines; D000644:Quaternary Ammonium Compounds; D012492:Salts; D012997:Solvents; C038123:alanylproline; C002956:alanylalanine; D014269:Trifluoroacetic Acid