title: Formation of pyroglutamylglutamine (or asparagine) diketopiperazine in 'non-classical' conditions: a side reaction in peptide synthesis.
abstract: Formation of by-products pyroglutamylglutamine diketopiperazine (5a) or pyroglutamylasparagine diketopiperazine (5b) were observed during the condensation of pyroglutamic acid active ester with C-protected glutaminyl(or asparaginyl)-proline derivatives. Successful synthesis of Glp-Gln(or Asn)-Pro-derivatives is possible after coupling of Glp-Gln(or Asn)-OH with proline-derivatives.
authors.affiliation: Physico-chemical Institute, Ukrainian Academy of Sciences, Odessa.
authors.forename: A A
authors.initials: AA
authors.lastname: Mazurov
authors.forename: S A
authors.initials: SA
authors.lastname: Andronati
authors.forename: T I
authors.initials: TI
authors.lastname: Korotenko
authors.lastname: Gorbatyuk VYa
authors.forename: Y E
authors.initials: YE
authors.lastname: Shapiro
mesh_terms: D000595:Amino Acid Sequence; D005069:Evaluation Studies as Topic; D009682:Magnetic Resonance Spectroscopy; D008722:Methods; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry; D010456:Peptides, Cyclic / Q000138:chemical synthesis*; D010879:Piperazines / Q000138:chemical synthesis*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives
chemical_list: D009842:Oligopeptides; D010456:Peptides, Cyclic; D010879:Piperazines; C083164:pyroglutamylglutamine diketopiperazine; C083163:pyroglutamylasparagine diketopiperazine; D011761:Pyrrolidonecarboxylic Acid