A computational approach to the synthesis of 1,3,5-thiadiazinane-2-thiones in aqueous medium: theoretical evidence for water-promoted heterocyclization

One pot synthesis of 5-hydroxyalkylated thiadiazine thiones: Implication in pain management and bactericidal properties

The synthesis of a new series of thiadiazine thiones including 5-(2-hydroxyethyl)-3-alkyl/aryl-1, 3, 5-thiadiazine-2-thiones (1-5), 5-(2-hydroxypropyl)-3-alkyl/aryl-1, 3, 5-thiadiazine-2-thiones (6-8), 3,5-dipropyl-1, 3, 5-thiadiazine-2-thione (9) and (2-(5-alkyl/aryl-6-thioxo-1, 3, 5-thiadiazine-3-yl) alkyl acetate/benzoate) (10-17) was accomplished via one pot reaction. The structures of the synthesized compounds were characterized through NMR and Mass spectrometry. The anti-nociceptive activity of compounds was performed on BALB/C mice by hot plate method, where compounds 3, 5 (50 μg/kg), and 8 (50, 100 μg/kg) exhibited significant effect (P < 0.01, P < 0.05) in latency time of 15, 30, and 60 min, while compounds 6 and 16 (100 μg/kg) exhibited significant effect (P < 0.01, P < 0.05) in latency time interval of 15 and 30 min. Compounds 1, 12-13, and 15 showed moderate activity. Among the tested hits, compounds 5 (17.3 ± 2.2), 11 (16.2 ± 2.1), and 8 (16.1 ± 2.1) showed significant anti-nociceptive potential. Molecular docking studies on the most active anti-nociceptive hits indicated that the activity might be attributed to the ability of the compounds to target μ-opioid receptor (μOR) effectively. Furthermore, compounds 14 and 11 showed anti-bacterial activity against Pseudomonas aeruginosa and MSRA with MIC of 40.97 and 54.77 μg/mL, respectively. In addition, the predicted ADMET profile of 5, 9, and 11 indicates that these molecules follow the drug-likeness criteria, and their activity can be enhanced through structural optimization.

New series of 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazine thione (THTT) derivatives: Synthesis and potent antileishmanial activity

Four series of heterocyclic compounds, namely, tetrahydro-2H-1,3,5-thiadiazine thione derivatives were synthesized in good to excellent yields and were screened for their in vitro antileishmanial activities against Leishmania major (promastigotes). Most of the compounds showed significant antileishmanial activity within the range of IC₅₀ = 15.48-39.36 μM when compared with standard pentamidine (IC₅₀ = 14.95 μM). The structure-activity relationship showed that N-3 and N-5 substituents have a key role against leishmanicidal activity. The ester analogues (series B) were found to have a 1.5 to 5-fold reduced activity compared to their acidic counterparts. Cytotoxicity against mammalian mouse fibroblast 3 T3 cells was also evaluated and compared between the acid and its ester analogue. The reduction of antileishmanial activity and loss of toxicity in the newly developed THTT ester derivative indicates that these compounds can be used as a template study for the production of effective antileishmanial ester prodrugs.

Thiadiazines, N,N-heterocycles of biological relevance

The 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazine-2-thione scaffold has found many applications in recent years. This review is aimed at highlighting the most important aspects of these compounds: Synthesis, spectroscopic characterization and biological activities. How the chemical nature of N-substituents influences the overall activity and cytotoxicity profile will also be discussed.

Thiadiazine derivatives as antiprotozoal new drugs

The 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazine-2-thione scaffold have found many applications in recent years. This review is aimed at highlighting the most important aspects about these compounds: synthesis, spectroscopic characterization and antiprotozoan activities. How the chemical nature of N-substituents influences the overall activity / cytotoxicity profile will also be discussed.