Acta Crystallographica Section E (Feb 2014)
Dimethyl 5-acetyl-1-hydroxy-4-methyl-1H-pyrrole-2,3-dicarboxylate, an oxidation-resistant N-hydroxypyrrole
Abstract
The title compound, C11H13NO6, exhibits an intramolecular O–H...O=C hydrogen bond between the N-hydroxyl H atom and carbonyl O atom of the neighboring acetyl group. This finding contradicts a previously published model in which the hydrogen bond was postulated to occur with the neighboring carbomethoxy group. This relatively strong hydrogen bond [O—H...O: D = 2.5583 (11) Å and θ = 152°] may underlie the resistance of the title compound to oxidation into the corresponding nitroxide.