Synthesis and Biological Activities of Some Novel Triazolothiadiazines and Schiff Bases Derived from 4-Amino-3-(4-hydroxyphenyl)-1H-1,2,4-triazole-5(4H)-thione

A series of novel 4-(6-substituted-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)phenols (5a–5n) and (E)-4-substituted-3-(4-hydroxyphenyl)-1H-1,2,4-triazole-5(4H)-thiones (6a– 6h) has been synthesized in high yields. The structures of all the title compounds have been determined by elemental analysis, IR, MS, 1H NMR, and 13C NMR, and the compound 5a was investigated with X-ray crystallography (CCDC No. 666889). Most of the title compounds possessed high plant growth–regulating activities. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.