Charge density of a putative intermediary product in the total synthesis of the cephalotaxine
Résumé
A high resolution diffraction measurement have been performed on a putative precursor of cephalotaxine; using a Brücker CCD detector. The compound crystallizes in P21/n space group (V = 1174.49(2) Å-3). 161121 reflections were collected leading to 10690 independent reflections up to 1,11 Å-1 (Rint = 0,0215). Multipole refinement (Hansen and Coppens model [1]) converges with reliability factors (R(F) = 0,0283 and GOF = 1,32). Electron deformation maps show up a strong delocalization over the four cycles. The calculation of the atomic net charges deduced from a k refinement are in agreement with the reactivity (or the non-reactivity) of the compound. The topological properties at the bond critical points (3,-1) are reported and are also in a quite good agreement with the chemistry. Finally the electrostatic potential has been calculated [2] and two different representations are used in order to characterize the compound: 3D isopotential surfaces, and 3D isodensity molecular surface colored by the electrostatic potential (figure). [1] Hansen N. Coppens P.,
Origine : Fichiers produits par l'(les) auteur(s)