“…Equation 116was log (1/C) = 1.850* -0.945*2 -7.90EHomo + 5.117 (116) n = 6, r = 0.975 log (1/C) = 1.200*r + 1.633*x + 0.543 (117) n = 16, r = 0.926, s = 0.615 log (1/C) = 1.213*r + 1.205*x + 0.861 (118) n = 16, r = 0.926, s = 0.598 derived for the mouse writhing assay of imidazolines,159 and eq 117 and 118 were obtained for mouse tail flick and writhing assays, respectively, of the derivatives of XXXVI. 160 In eq 116, there is, however, one additional term, EHOmo> which denotes the energy of the highest occupied molecular orbital in a quantum mechanical treatment of a 7r-electron system. The involvement of this term refers to a charge-transfer phenomenon taking place in a drug-receptor interaction.…”