52214-59-2Relevant academic research and scientific papers
Selective Heteronuclear NOE Enhancements in Benzoheterocycles. Effect of Ring Size on Indirect Three-Spin Effects
Redondo, Jordi,Sanchez-Ferrando, Francisco,Valls, Montserrat,Virgili, Albert
, p. 511 - 517 (2007/10/02)
The 80 MHz 1H NMR and 20 MHz 13C NMR spectra of five 4-methylcoumarins, six 4-methyl-2(1H)-quinolones and nine 3-methylbenzofurans, including six new compounds, were fully assigned.Homonuclear 1H NOEs and selective heteronuclear 13C NOEs were measured after low-power pre-saturation of the methyl protons.Indirect, negative heteronuclear NOE enhancements were found in suitable three-spin systems of the 13C-1H- type, and their magnitude was found to be dependent on ring size.The first examples of indirect, heteronuclear NOE enhancements on non-protonated carbons are described.KEY WORDS Heteronuclear NOE Selective heteronuclear 13C NOE Indirect negative NOE 13C-1H- three-spin effects Coumarins 2(1H)-Quinolones Benzofurans.
Mechanisms of Nucleophilic Attack at Carbon-Nitrogen Double Bonds. The Reaction of Aryl N-Arylbenzimidates with Methoxide Ion
Rowe, Jeffrey E.
, p. 1259 - 1262 (2007/10/02)
Rate data for the reaction of three series of aryl N-arylbenzimidates with methoxide ion at 303 K are presented.Linear Hammett plots were obtained for each series.Solvent isotope effects have also been measured.The results are interpreted in terms of rate-determining formation of a tetrahedral intermediate, irrespective of the nature of the substituent.
