A pipecolic acid (Pip)-containing dipeptide, Boc-<scp>D</scp>-Ala-<scp>L</scp>-Pip-NH<sup><i>i</i></sup>Pr
作者:Claude Didierjean、Guy Boussard、André Aubry
DOI:10.1107/s0108270102008715
日期:2002.7.15
The title dipeptide, 1-(tert-butoxycarbonyl-D-alanyl)-N-isopropyl-L-pipecolamide or Boc-D-Ala-L-Pip-(NHPr)-Pr-i (H-Pip-OH is pipecolic acid or piperidine-2-carboxylic acid), C17H31N3O4, with a D-L heterochiral sequence, adopts a type II' beta-turn conformation, with all-trans amide functions, where the C-terminal amide NH group interacts with the Boc carbonyl O atom to form a classical i+3 --> i intramolecular hydrogen bond. The C-alpha substituent takes an axial position [H-alpha (Pip) equatorial] and the trans pipecolamide function is nearly planar.