title: Cyclo(L-leucyl-alpha,beta-dehydrophenylalanine): the first diketopiperazine containing an alpha,beta-dehydrophenylalanine residue.
abstract: The title compound (systematic name: 3-benzylidene-6-isobutylpiperazine-2,5-dione), C15H18N2O2, an alpha,beta-dehydrophenylalanine containing diketopiperazine, crystallizes in the space group P1 with two molecules in the asymmetric unit arranged antiparallel to one another. The alpha,beta-dehydrophenylalanine (DeltaPhe) residue in this cyclic peptide retains its planarity but deviates from the standard conformations observed in its linear analogues. Each type of molecule forms a linear chain with molecules of the same type via pairwise N-H...O hydrogen bonds, while weaker C-H...O interactions link the chains together to form a three-dimensional network.
authors.affiliation: Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: A
authors.initials: A
authors.lastname: Bagaria
authors.forename: S
authors.initials: S
authors.lastname: Ramakumar
authors.forename: M
authors.initials: M
authors.lastname: Gupta
authors.forename: V S
authors.initials: VS
authors.lastname: Chauhan