RELATIONSHIP BETWEEN BIOLOGICAL-ACTIVITY AND DIPOLE-MOMENT IN BENZO[A]PHENOTHIAZINES

Relationship between the biological activity and two different dipole moments were investigated in 9 benzo[a] phenothiazines [1-8] by calcul ating the dipole moment with the PM3 method. 12H-Benzo[a]phenothiazine [1], 9-methyl-12H-benzo[a]phenothiazine [2], 10-methyl-12H-benzo[a]ph enothiazine[3] and 11-methyl-12H-benzo[a]phenothiazine [4] induced mon ocytic differentiation of human myelogenous leukemic cell lines and di splayed antitumor activity. These active compounds showed a significan tly smaller value of calculated ground-state dipole moment (mu(g)) and larger value of first excited-state dipole moment (mu(e)). The mu(e)/ mu(g) ratio of four active compounds [1-4] ranged from 3.25 to 4.38, w hereas that of three inactive compounds [5,6,7] ranged from 1.77 to 2. 72. These two different dipole moments might be useful parameters for estimation of the biological activity of benzo[a]phenothiazines [1-8].