Antithyroid activity of 2, 4-dihydro-3H-1, 2, 4-triazole-3-thiones and thiosemicarbazones was tested by measuring the uptake ratio of thyroid : serum (T/S) of 125I through the mouse thyroid. Substitution with an alkyl group at the 5-position of the triazole nucleus remarkably increased the activity but substitution at the N-2 and/or N-4 positions caused a significant decrease in the activity, indicating the necessity of unsubstituted thioureylene moiety for the antithyroid activity. Thiosemicarbazone derivatives which are an open ring structure of triazoles showed comparable antithyroid activities to those in a ring form, but one thiosemicarbazone showed a much higher toxicity than the corresponding ring form compound. This suggests that the ring structure is not essential for the activity but is necessary to reduce toxic effect. Of fourteen compounds tested, 5-methyl-2, 4-dihydro-3H-1, 2, 4-triazole-3-thione was the most potent antithyroid compound with low toxicity, with a potency tenfold that of propylthiouracil, a drug currently used.
                                    通过测量甲状腺:血清(T/S)对小鼠甲状腺 125I 的吸收比,测试了 2,4-二氢-3H-1,2,4-三唑-3-
硫酮和
硫代
氨基甲酸盐的抗甲状腺活性。在三唑核的 5 位上用烷基取代可显著提高活性,但在 N-2 和/或 N-4 位上取代会导致活性显著降低,这表明未取代的
硫脲基对抗甲状腺活性的必要性。作为三唑的开环结构的
硫代
氨基羰基衍
生物显示出与环状结构的化合物相当的抗甲状腺活性,但其中一种
硫代
氨基羰基化合物显示出比相应的环状结构化合物更高的毒性。这表明,环状结构对于活性并不是必不可少的,但对于降低毒性作用却是必要的。在测试的 14 种化合物中,5-甲基-2, 4-二氢-3H-1, 2, 4-三唑-3-
硫酮是毒性最低的抗甲状腺化合物,其效力是目前使用的丙基
硫脲嘧啶的 10 倍。