TY - JOUR
T1 - On the structure of 3-acetylamino-5-methyl-1,2,4-oxadiazole and on the fully degeneraterearrangements (FDR) of its anion: astimulating comparison between the resultsof ‘in-silicon chemistry’ and ‘laboratorychemistry’
AU - Pace, Andrea
AU - Buscemi, Silvestre
AU - Barone, Giampaolo
AU - Mugnoli, Angelo
AU - Pani, Marcella
AU - Lanza, Camilla Zaira
AU - Spinelli, Domenico
PY - 2009
Y1 - 2009
N2 - An accurate crystal structure determination has provided evidence for a planar conformation for 3-acetylamino-5-methyl-1,2,4-oxadiazole (5), in agreement with quantum-mechanical calculations in the gas phase. In the crystal, a series of strong intermolecular N7H7...O9 hydrogen bonds link the amido groups of different molecules, causing the formation of infinite parallel ordered chains. The effect of the DMSO solvent on the energy and charge distribution of compound 5 and on its relevant 5S anion, involved in a fully degenerate rearrangement (FDR), has been deepened by quantum-mechanical DFT calculations. The calculated energy barrier for the FDR increases in going from in vacuo to DMSO, in agreement with previsions based on the Hughes and Ingold rules concerning the nucleophilic substitution of an anionic reagent (the deprotonated amido group in the side chain) on a neutral substrate (the 1,2,4-oxadiazole ring).
AB - An accurate crystal structure determination has provided evidence for a planar conformation for 3-acetylamino-5-methyl-1,2,4-oxadiazole (5), in agreement with quantum-mechanical calculations in the gas phase. In the crystal, a series of strong intermolecular N7H7...O9 hydrogen bonds link the amido groups of different molecules, causing the formation of infinite parallel ordered chains. The effect of the DMSO solvent on the energy and charge distribution of compound 5 and on its relevant 5S anion, involved in a fully degenerate rearrangement (FDR), has been deepened by quantum-mechanical DFT calculations. The calculated energy barrier for the FDR increases in going from in vacuo to DMSO, in agreement with previsions based on the Hughes and Ingold rules concerning the nucleophilic substitution of an anionic reagent (the deprotonated amido group in the side chain) on a neutral substrate (the 1,2,4-oxadiazole ring).
UR - http://hdl.handle.net/10447/40877
M3 - Article
VL - 22
SP - 1086-
JO - Journal of Physical Organic Chemistry
JF - Journal of Physical Organic Chemistry
SN - 0894-3230
ER -