Design, Synthesis and Pharmacological Evaluation of New Nonsteroidal Antiinflammatory 1,3,4-Thiadiazole Derivatives

Synthesis of 5-arylidine amino-1,3,4-thiadiazol-2-[(N-substituted benzyol)]sulphonamides endowed with potent antioxidants and anticancer activity induces growth inhibition in HEK293, BT474 and NCI-H226 cells

Abstract

A series of imines 5-amino-1,3,4-thiadiazol-2-[(N-substituted benzyol)]sulphonamide derivatives were synthesized from various aromatic aldehydes and substituted with benzoyl acetazolamides under different reaction conditions and were evaluated for their antioxidant and free radical scavenging, antimitotic activity by Allium cepa meristem root model and cytotoxicity activity against HEK 293 (human epidermal kidney cell line), BT474 (breast cancer cell line) and NCI-H226 (lung cancer cell line) by MTT assay. Some of the synthesized compounds showed moderately potent cytotoxicity compared to indisulam.

Graphical abstract

A series of imines 5-amino-1,3,4-thiadiazol-2-[(N-substituted benzyol)]sulphonamide derivatives (9a–j); 5-amino-1,3,4-thiadiazol-2-[N-(substituted benzoyl)]sulphonamide (4a–g); 5-(4-acetamido phenyl sulphonamido)-1,3,4-thiadiazol-2-[N-(substituted benzoyl)]sulphonamide (6a–g); and 5-(4-amino phenyl sulphonamido)-1,3,4-thiadiazol-2-[N-(substituted benzoyl)]sulphonamide (7a–g) were synthesized from acetazolamide and were investigated for the in vitro anticancer by MTT assay, free radical scavenging and antimitotic activity by Allium cepa root meristem model. Experimental observations indicate that synthesized compounds were moderately potent anticancer agents.

Synthetic methods, chemistry, and the anticonvulsant activity of thiadiazoles

The chemistry of heterocyclic compounds has been an interesting field of study for a long time. Heterocyclic nucleus 1,3,4-thiadiazole constitutes an important class of compounds for new drug development. The synthesis of novel thiadiazole derivatives and investigation of their chemical and biological behavior have gained more importance in recent decades. The search for antiepileptic compounds with more selective activity and lower toxicity continues to be an active area of intensive investigation in medicinal chemistry. During the recent years, there has been intense investigation of different classes of thiadiazole compounds, many of which possess extensive pharmacological activities, namely, antimicrobial activity, anticonvulsant, antifungal antidiabetic, anti-inflammatory, antioxidant, and antituberculosis activities, and so forth. The resistance towards available drugs is rapidly becoming a major worldwide problem. The need to design new compounds to deal with this resistance has become one of the most important areas of research today. Thiadiazole is a versatile moiety that exhibits a wide variety of biological activities. Thiadiazole moiety acts as "hydrogen binding domain" and "two-electron donor system." It also acts as a constrained pharmacophore. On the basis of the reported literature, we study here thiadiazole compounds and their synthetic methods chemistry and anticonvulsant activity.

Synthesis of some novel heterocyclic compounds derived from diflunisal hydrazide as potential anti-infective and anti-inflammatory agents

Three novel series of 2',4'-difluoro-4-hydroxybiphenyl-3-carboxylic acid derivatives namely 4-substituted-1,2,4-triazoline-3-thiones (4a-g); 2-substituted-1,3,4-thiadiazoles (5a-g) and 2-substituted-1,3,4-oxadiazoles (6a-g) have been synthesized. Twenty-one of the newly synthesized compounds were tested against various bacteria, fungi, yeast species and virus. In addition, we have replaced the carboxylic acid group of diflunisal with heterocycles and the anti-inflammatory activity of heterocycles reported here. Compound (5d) showed activity against Escherichia coli A1 and Streptococcus pyogenes ATCC-176 at a concentration of 31.25 microg/mL, whereas cefepime, the drug used as standard, has been found less active against the bacteria mentioned above. Compound (4b) has exhibited activity against Aspergillus variecolor and Trichophyton rubrum at a concentration of 31.25 and 15.25 microg/mL, whereas Amphotericin B, the drug used as standard, has been found less active against the yeast and fungi. The highest antiviral activity was found in the 1,3,4-thiadiazole derivative (5a) having a methyl group at 2nd position against Sindbis virus at 9.6 microg/mL. Compound (4c) exhibited the highest anti-inflammatory activity (73.03%) whereas diflunisal, the drug used as standard, has been found less active (24.16%). Compound (5f) presented similar antinociceptive activity with the standard drug (paw withdrawal latency was 19.21 s compared to that of diflunisal which was 19.14s, in hot plate test).