Y = Y′ = CO2Me, whereas when Y = CO2Me, Y′ = CN or YY′ = Meldrum′s acid residue the structure is that of the enol (5) YY′C=C(OH)NHPr-i. The solid-state 13C spectra indicate structure 6 when Y = CO2Me, Y′ = CO2R, R = Me, CH2CF3 and an enol structure for the other compounds studied. 1H, 13C and when available 19F NMR spectra showed that the enol/amide composition in solution is structure and solvent dependent
形式结构为YY'CHCONHPr- i(6),Y,Y'= CO 2 Me,CO 2 CH 2 CF 3,CN的八个N-异丙基化合物;YY'= Meldrum的酸残基;Y = CO 2 Me,Y′= CO 2 CH 2 CF 3,CN;Y = CO 2 Me,Y′= CO 2 CH 2 CF 3。Y = CO 2 CH 2 CF 3,CO 2 CH(CF 3)2,Y'= CN和N - t制备了Meldrum酸的丁基衍生物,并在固态和溶液中研究了它们的结构。X射线衍射数据表明,当Y = Y′= CO 2 Me时,固态结构为酰胺6的结构,而当Y = CO 2 Me时,Y′= CN或YY′= Meldrum的结构。酸残基的结构是烯醇(5)YY'C = C(OH)NHPr- i的结构。固态13 C ^光谱表明结构6当Y = CO 2 Me中,Y'= CO 2 R,R = Me中,CH 2 CF 3和
Stable Enols of Amides ArNHC(OH)C(CN)CO<sub>2</sub>R. <i>E</i>/<i>Z</i> Enols, Equilibria with the Amides, Solvent Effects, and Hydrogen Bonding
two enols (E and Z) are the major products, and the amide is the minor product or not observed at all (K(Enol) 1.04-9 (CD(3)CN, 298 K) and 3 to >/=100 (THF, 300 K)). The percentage of the amide and the Z-enol increase upon an increase in temperature. In all solvents, the percent enol is higher for 9 than for 7. In CD(3)CN, more enol is observed when the aryl group is more electron-donating. The spectra