Premium
The Structure of Pyroergotamine
Author(s) -
Day Roberata O.,
Day Victor W.,
Wheeler Desmond M. S.,
Stadler Paul A.,
Loosli HansRudolf
Publication year - 1985
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19850680322
Subject(s) - chemistry , dihedral angle , residue (chemistry) , crystallography , ring (chemistry) , molecule , stereochemistry , crystal structure , organic chemistry , hydrogen bond
The molecular structure of pyroergotamine has been determined by single‐crystal X‐ray diffraction analysis to be the pyruvoyldiketopiperazine 1 . The diketopiperazine ring exists in a folded or boat conformation, with a dihedral angle of 40° between the two almost planar peptide units. The R‐group of the phenylalanine residue occupies a quasi‐axial position of the diketopiperazine ring, while that of the proline residue is in a quasi‐equatorial position. Puzzling spectroscopic and chemical properties of the compound can be rationalised in terms of crowding within the molecule.