Synthesizing Unique Triazolo[3,4‐b][1,3,4]Thiadiazines as Effective Anti‐Alzheimer's Medications: An In Vitro Study

A new class of triazolo[3,4-b][1,3,4]thiadiazines has been developed by combining thiocarbohydrazide and ethyl cyanoacetate, resulting in the formation of a triazole-3-thione derivative. Afterwards, the compound underwent a reaction with 2-bromoacetamide derivative and chloroacetic acid to yield the corresponding triazolo-thiadiazine derivatives, 6-amino-5-(aminomethyl)-3-methyl-N-(5-methylthiazol-2-yl)-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine-7-carboxamide derivative and 5-(aminomethyl)-3-methyl-5H-[1,2,4]triazolo[3,4-b][1,3,4]- thiadiazin-6(7H)-one derivative which can serve as a precursor in subsequent processes. Furthermore, when α-bromo ketones were treated with triazole derivative, which was prepared by mixing thiocarbohydrazide with 4-hydroxybenzoic acid, 5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)phenol derivatives were produced. To identify each of the produced compounds, advanced spectroscopic techniques such as mass spectrometry, proton nuclear magnetic resonance (¹H NMR), carbon-13 NMR (¹³C NMR), and Fourier-transform infrared spectroscopy were utilized. Most of the newly generated compounds showed significant inhibitory effects in vitro against the acetylcholinesterase enzyme, making them potential candidates for treating Alzheimer's disease. Two compounds in particular, triazole-3-thione derivative, and 4-(6-(benzofuran-2-yl)-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)phenol showed the most promising therapeutic potential with IC₅₀ values of 14.58 ± 0.45 and 22.53 ± 0.68 µg/mL, respectively.