593 Ethyl dichloroacetate Cl2CH-0 4.33.1.35 O-CH2-CH3 Low(shielding)feld High (shielding)field deshielded protons shielded protons 为=7H2 CHCI TMS ppm 7.26 5.93 4.33 1.35 0.0 Figure 1.2.'H NMR spectrum of ethyl dichloroacetate(CDCla.25C.80 MHz).The proton of the CHCI2 group is less shielded(more strongly deshielded)in comparison with the protons of the CH2 and CH,residues ,> 12 3 one coupling constant two coupling constants two similar coupling constants three coupling constants quartet doublet of doublets pseudotriplet threefold doublet Figure 1.3.Quartet,doublet of doublets,pseudotriplet and threefold doublet(doublet of doublets of doublets) 2nl+1 Rule:I=1/2 for 1H,19F,13C and 15N;I=1 for 2H; n:number of vicinal protons 2nI+1 Rule: I=1/2 for 1H, 19F, 13C and 15N; I=1 for 2H; n: number of vicinal protons