ICI 180080, a novel selective thromboxane receptor antagonist: synthesis and relative activity

The preparation of a novel potent thromboxane receptor antagonist ICI 180080, 5(Z)-7-[2,2-dimethyl-4-(2-hydroxyphenyl)-1,3-dioxan-cis-5-yl] heptenoic acid, is described together with its methyl ether and methyl ester. Thromboxane antagonist pA2 data against U 46619 is presented for rabbit thoracic aorta in-vitro (ICI 180080, pA2 = 7.5). The relative antagonist pA2 values obtained are discussed in terms of the chemical structure of the molecules. The potent activity of ICI 180080 is attributed to a specific orientation of the phenolic oxygen, due to an intramolecular hydrogen bond.