At 66 parts per million in the feed, robenzidene is highly effective in preventing chicken coccidiosis caused by any one of eight Eimeria species. Three times this dose is safe for broiler chickens. In dogs and rats, the toxicity was relatively low over a period of 90 days. In laboratory trials, the drug completely prevents oocyst production by seven species and greatly reduces oocyst production by Eimeria maxima.

The title compounds were prepared to investigate their potential as thromboxane synthetase inhibitors as well as antihypertensive agents. Imidazoles VIII and triazoles X were prepared to examine the effects of aromatic substitution, chain length, and heterocycle substitution upon biological activity. Imidazoles VIII and triazoles X were thromboxane synthetase inhibitors that did not inhibit prostacyclin formation. The most interesting thromboxane synthetase inhibitors prepared were 4-chloro-, 4-(trifluoromethyl)-, and 4-bromobenzamide derivatives of (1H-imidazol-1-yl)alkylamines with C5-C8 alkyl chains separating the heterocycle from the amide moiety, while the most active antihypertensive agents were 3- or 4-chloro-, -bromo, or -(trifluoromethyl)benzamides with C3 alkyl chains. The best thromboxane synthetase inhibitors in this study were up to 10 times more potent than the standard, dazoxiben (UK 37,248).

The quinazolinedione, quinazolinone, and 1,2,3-benzotriazinone title compounds were prepared as analogues of N-[(1H-imidazol-1-yl)alkyl]-1H-isoindole-1,3(2H)-diones which were the subject of a previous report from our laboratories. These compounds were evaluated as thromboxane (TX) synthetase inhibitors and as antihypertensive agents. While each series of compounds had activity both as TX synthetase inhibitors and as antihypertensives, the best compounds were N-[(1H-imidazol-1-yl)alkyl]quinazoline-2,4(1H,3H]-diones (V). In general these compounds were all selective enzyme inhibitors at least equipotent with the standard dazoxiben. These compounds were also very active antihypertensive agents as determined in SHR. The SAR is discussed for both types of activity. Compound 20a was further evaluated for TX formation inhibiting properties in several other platelet types both in vitro and ex vivo and is between 100 and 1000 times more potent than dazoxiben.

A series of 5-(1-piperazinyl)-1H-1,2,4-triazol-3-amines was synthesized and screened for antihypertensive and diuretic activity in spontaneously hypertensive rats (SHR). One compound, 5-[4-[(3-chlorophenyl)methyl]-1-piperazinyl]-1H-1,2,4-triazol-3-am ine (8), was selected to define the mechanism of its antihypertensive activity. Studies in SHR suggest ganglionic blocking activity. Short-lived antihypertensive activity was observed in conscious renal hypertensive dogs.

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