NMR Analysis of Substituent Effect of Arymethylene‐malononitriles and Malonates

Abstract

A series of arylmethylene-malononitriles and malonates were prepared from the condensation of arylaldehydes and malononitriles and malonates, respectively. The function of substituents on the carbon-13 chemical shifts of the Ca and Cb was studied. The correlation between Hammett's constants and the substituent chemical shifts demonstrates a negative slope for Ca and positive for C b (1, C a : r = -3.877, r 2 = 0.979; C b : r = 6.899, r 2 = 0.984; 2, C a : r = -2.817, r 2 = 0.926; C b : r = 5.355, r 2 = 0.950). The large slopes for C b for both series compounds resemble our previous studies on the arylcyclopropanes. The relaxation time of both proton and carbon are slightly affected by the size of substituents. In the viscosity study, an inverse-law relationship between relaxation time and viscosity was observed.