title: Benzotriazole-mediated synthesis of aza-peptides: en route to an aza-leuenkephalin analogue.
abstract: Novel N-(N-Pg-azadipeptidoyl)benzotriazoles 20a-e couple efficiently with α-amino acids 21a-e, dipeptides 22a-c, aminoxyacetic acid 23a, depsidipeptide 23b, and α-hydroxy-β-phenylpropionic acid 27 yielding, respectively, azatripeptides 24a-g, azatetrapeptides 25a,b, a hybrid azatripeptide with an oxyamide bond 26a, a hybrid azatetrapeptide with an ester bond 26b, and a hybrid azatripeptide with an ester bond 28. A new protocol for the synthesis of N-Pg-azatripeptides 33a,b and 35a,b, each containing a natural amino acid at the N-terminus, avoids the low coupling rates of the aza-amino acid residue and enables the solution-phase synthesis of an azaphenylalanine analogue of Leu-enkephalin 40.
authors: Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA.
authors: Nader E
authors: NE
authors: Abo-Dya
authors: Suvendu
authors: S
authors: Biswas
authors: Akash
authors: A
authors: Basak
authors: Ilker
authors: I
authors: Avan
authors: Khalid A
authors: KA
authors: Alamry
authors: Alan R
authors: AR
authors: Katritzky
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry*; D001372:Aza Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D004151:Dipeptides / Q000138:chemical synthesis* / Q000737:chemistry; D004743:Enkephalin, Leucine / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry*; D011422:Propionates / Q000138:chemical synthesis* / Q000737:chemistry; D014230:Triazoles / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D001372:Aza Compounds; D004151:Dipeptides; D010455:Peptides; D011422:Propionates; D014230:Triazoles; C582734:alpha-hydroxy-beta-phenylpropionic acid; D004743:Enkephalin, Leucine; C012771:benzotriazole