1-(2-Phenoxyethyl)-1H-imidazole was found to be an inhibitor of thromboxane (TxA2) synthetase, but it also inhibited the adrenal cytochrome P-450 enzyme steroid 11 beta-hydroxylase. The preparation of a series of analogues is described, and activity against TxA2 synthetase, PGI2 synthetase, cyclooxygenase, and steroid 11 beta-hydroxylase is discussed. Potency against TxA2 synthetase was increased by introduction of a carboxyl group at a suitable distance from the imidazole ring. A distance of 8.1-8.8 A between N-1 of the imidazole and the carboxyl carbon was found to be optimal. Introduction of a carboxyl group also had the effect of reducing activity against steroid 11 beta-hydroxylase. The most potent and selective compound was found to be 4-[2-(1H-imidazol-1-yl) ethoxy]benzoic acid (14).

A series of substituted benzenedisulfonamide carbonic anhydrase inhibitors is described and their anticonvulsant activities are listed. One compound, 4-(4-methoxypiperidinosulfonyl)-2-chlorobenzenesulfonamide (19, UK-12130), was found to have anticonvulsant activity in animals at a dose level that gave only a minimal diuretic effect. 19 selectively increased cerebral blood flow in animals and man without producing an unacceptable level of metabolic acidosis.

The preparation of a series of 1H-imidazol-1-yl-substituted benzo[b]furan-, benzo[b]thiophene-, and indolecarboxylic acids is described. Most of the compounds were potent inhibitors of TxA2 synthetase in vitro, and the distance between the imidazole and carboxylic acid groups was found to be important for optimal potency. The most potent compound in vivo was 6-(1H-imidazol-1-ylmethyl)-3-methylbenzo[b]thiophene-2-carboxylic acid (71), which, in conscious dogs, showed a similar profile of activity to that of dazoxiben (1).

The preparation of a series of 2-(1H-imidazol-1-ylmethyl)-substituted carboxylic acids of benzo[b]furan, benzo-[b]thiophene, indole, and naphthalene is described. All compounds showed a similar level of activity as TxA2 synthetase inhibitors in vitro, having IC50 values between 1 and 7 X 10(-8) M. In the cases examined, compounds had, at most, only negligible activity against PGI2 synthetase, cyclooxygenase, and steroid 11 beta-hydroxylase. The benzo[b]thiophenes generally showed the greatest potency in vivo, and compounds 72, 73, and 75 caused almost complete inhibition of thromboxane production for 6 h after oral administration of 0.5 mg/kg to conscious dogs. In the case of 73 and 75, thromboxane production was still inhibited by 80% after 24 h.