摘要
本文采用酰氯路线由甲基丙烯酰氯同苯胺、对甲苯胺、邻甲苯胺、对溴苯胺、对硝基苯胺、邻硝基苯胺、α-萘胺等反应制得了一系列N-芳基取代甲基丙烯酰胺（N-ArMA）。给出了这些新单体的<sup>1</sup>H-NMR谱图.研究了这些单体中苯环上不同取代基及同一取代基在不同取代位置上对质子的化学位移的影响.研究结果表明,不同的取代基由于不同的电子效应使苯环上质子峰发生位移,按向低场位移顺序是:-NO<sub>2</sub>】-Br】-H】-CH<sub>3</sub>同样的取代基在邻位取代使苯环质子移向低场更显著。化学位移的实测值与经验公式计算值比较一致。
The N - Arylmethacrylamides including N -Phenylmethacrylamide( N - PhMA), N-p-Tolylmelhacrylamide (N-p-TMA), N-o-Tolylmethacrylamide(N-o-TMA),
N -p-Bromomethacrylamide( N-p- BrPhMA),N-p-Nitrophenylmethacrylamide (N-p-NPhMA), N-o-Nitrophenylmethacrylamide (N-o-NPhMA), were prepared via the acid route and the chemical shifts of these N-Arylmethacrylamide were determined ( see Table 1) on a Varian FT-80A NMR spectrometer.
The substituent groups affect the chemical shifts of adjacent aryl protons as shown in Table 2. Since chemical shifts depends on the electron density around the aryl proton, the methyl group, which is a weak electron releasing group on the benzene ring, increases the electron density on the aryl proton thus will tend to cause an up-field shift; the nitro group, which is a strongly electron withdrawing group on the benzene ring, decreases the electron density on the aryl proton, thus will tend to cause a down -field shift. As an evidence the shifts dH are 7. 54ppm, 7. 44ppm, 7. 76ppm for N-PhMA, N-p-TMA, and N-p-NPhMA, respectively.
In compounds N-o-NPhMA and N-o-TMA the protons labelled dH at lower fields than those in N -p-NPhMA and N -p -TMA, since the former lies in the deshielding zone of the carbonyl group.
This is illustrated below: The values of the chemical shifts of the six kinds of N-Aryimcthacrylamide were estimated so as to obtain a good agreement between observed and calculated.
(see Table 2 )
出处
《波谱学杂志》
CAS
CSCD
1989年第1期13-20,共8页
Chinese Journal of Magnetic Resonance
