Aminothiadiazoles.

2-Amino-1,3,4-thiadiazole (ATDA) and some of its analogs have antitumor, uricogenic, and teratogenic activity. In general, these effects are reversed by nicotinamide. Although ATDA is not extensively metabolized in animals, a portion is apparently converted to an NAD+ or nucleotide analog that is a potent inhibitor of IMP dehydrogenase. Inhibition of this enzyme is probably related to the increased de novo synthesis of uric acid that has been observed in man and in chick embryos. The moderate activity of ATDA against experimental tumors has led to clinical trials in man.