Cyclo(L-prolyl-L-N-methylphenylalanyl). Conformation in solution and in the crystal.
Detailed analysis of the proton and carbon-13 NMR spectra of cyclo(L-prolyl-L-N-methylphenylalanyl) in chloroform and methanol in relation to its nonmethylated analog provided information on the conformation of the title compound in solution as well as on the effect of N-methylation and solvation. The X-ray structure of the title compound in the crystalline state showed the same conformational features as the solution structure. The phenyl group folds over the diketopiperazine ring which resembles a flattened half-chair. Both amide bonds are considerably nonplanar. The pyrrolidine ring of proline shows a strong pucker at the ring junction with the largest chi 5 value hitherto observed.
Budĕsínský
M
M
Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, Prague.
Symerský
J
J
Jecný
J
J
Van Hecke
J
J
Hosten
N
N
Anteunis
M
M
Borremans
F
F
D004151:Dipeptides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation; D012996:Solutions; D014961:X-Ray Diffraction
D004151:Dipeptides; D010456:Peptides, Cyclic; D012996:Solutions; C076490:cyclo(prolyl-N-methylphenylalanyl)