Molecular and crystalline structures of three (S)-4-alkoxycarbonyl-2-azetidinones containing long alkyl side chains from synchrotron X-ray powder diffraction data.
Acta Crystallogr B
; 65(Pt 6): 724-30, 2009 Dec.
Article
in En
| MEDLINE
| ID: mdl-19923701
ABSTRACT
The (S)-4-alkoxo-2-azetidinecarboxylic acids are optically active beta-lactam derivatives of aspartic acid, which are used as precursors of carbapenem-type antibiotics and poly-beta-aspartates. The crystal structures of three (S)-4-alkoxo-2-azetidinecarboxylic acids with alkyl chains with 10, 12 and 16 C atoms were solved using parallel tempering and refined against the X-ray powder diffraction data using the Rietveld method. The azetidinone rings in the three compounds display a pattern of asymmetrical bond distances and an almost planar conformation; these characteristics are compared with periodic solid-state, gas-phase density-functional theory (DFT) calculations and MOGUL average bond distances and angles from the CSD. The compounds pack along [001] as corrugated sheets separated by approximately 4.40 A and connected by hydrogen bonds of the type N-H...O.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Acta Crystallogr B
Year:
2009
Document type:
Article
Affiliation country:
Venezuela