کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1401682 1501716 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Electronic effects on keto-enol tautomerism of p-substituted aryl-1,3-diketone malonates
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Electronic effects on keto-enol tautomerism of p-substituted aryl-1,3-diketone malonates
چکیده انگلیسی
Electronic effects on keto-enol tautomerism of 1-(p-substituted aryl)-1,3-diketone malonates 1-10 were determined and established by NMR-Hammett linear free energy relationships. In addition, tautomeric equilibrium constants were determined for the title compounds by 1H NMR in DMSO-d6, showing an increasing to diketo tautomer with the increasing in the temperature. In this context, the enol form becomes less stable with increasing temperature suggesting that the intramolecular hydrogen bonding of the cis enol-keto form are increasingly broken at higher temperatures. In general, the enolic form (rather than the keto) is the most stable conformation due to its six member cyclic structure fulfilled by an internal O-H … O hydrogen bond.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure - Volume 1101, 5 December 2015, Pages 162-169
نویسندگان
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