Development of a Suitable Method for the Synthesis of New Thiadiazoles Using Hydrazonoyl Halides

Abstract

Background: Hydrazonoyl halides and methylhydrazinecarbodithioate have been generally utilized in the synthesis of heterocycles. Methods: This study describes a new and simple method to prepare new thiadiazoles from the reaction of N-(naphthalen-1-yl)-2-oxopropanehydrazonoyl chloride or ethyl 2-chloro-2-(2-(naphthalen-1-yl)hydrazono)acetate with methylhydrazinecarbodithioate in the presence of basic medium under reflux. In this study, the synthetic schemes are designed to show the chemical reactions. Elements analysis, Fourier Transform Infrared Spectroscopy (FT-IR), Mass Spectrom-etry (MS), and Nuclear Magnetic Resonance (NMR) are used to identify and characterize the final compounds. Results: There are two ways to synthesize the final thiadiazoles molecules. The first can be through nucleophile substitution of thiolate of methylhydrazonecarbodithioate to the chlorinated carbon of hydrazonoyl. Hydrochloric acid is then removed to provide an S-alkylated intermediate. Methanethiol is eliminated from this intermediate by an in situ intra-molecular cyclocondensation process to give the final products. The subsequent [3+2] cy-cloaddition involving 1,3-dipolar cycloadditions of nitrilimines to C=S is succeeded by the re-moval of methanethiol. Conclusion: This approach utilizes affordable, readily accessible reagents and simple reaction conditions to produce new thiadiazole derivatives with satisfactory yields.