Synthesis and structure-activity relationships of a novel antifungal agent, ICI 195,739

Antifungal azole derivatives are known to have potential for inhibition of host P-450 systems, and, in the attempts to increase the antifungal specificity of the inhibitor by identification of extra receptor binding within the enzyme complex, initial synthesis was guided by the structural requirements of the natural lanosterol substrate. With the aid of computer graphics, the 3'-styryl functionality was identified as a key structural element. For metabolically stable systems, in vitro-in vivo correlations exist, but optimizing oral activity resulted in the production of compounds with unacceptably long elimination half-lives. A disconnection of this relationship was achieved in pairs of structural isosteres with metabolic nonequivalence (CN:CONH2/OCH3:OCF3) and led to the identification of ICI 195,739, a novel 3'-tetrafluoropropoxystyryl-substituted bistriazole tertiary alcohol, as the compound of choice.