Design and Synthesis of 2-Substituted Benzothiazole Derivatives as Antioxidant and Antimicrobial Agents

Abstract

Background: An upsurge in the number of antibiotic resistant microbial infections has warranted the discovery and developments of new antibiotics. This is a matter of grave concern for the effective therapy for search of novel antimicrobial agents. Literature is replete with the reports of involvement of oxidative stress due to imbalance between generation and neutralization of free radicals in many diseases. Heterocyclic compounds have been involved in the treatment of various disorders. Benzothiazole is one of such heterocyclic nucleus having benzene ring merged with thiazole ring. Among the various substitutions possible in this nucleus, substitutions at position-2 have already been reported with potential bioactivities. Thus different substituted compound have been synthesized which could serve as antimicrobials and antioxidant. Methods: Benzothiazole derivatives (B1-B7) were synthesized by two step reactions and the structures were confirmed through infrared, mass and NMR spectroscopy. The compounds were evaluated for in vitro antioxidant and antimicrobial activities using standard methods. Results: From the results of antibacterial and antifungal activity compound B4 was exhibited maximum activity against all the tested strains of microorganisms with the zone of inhibition 17.1-18.5 mm and MIC value 1.1-1.5 µg/mL. Compound B5 exhibited potent antioxidant activity. Conclusion: The compounds substituted with halogen on the aryl ring increased the antimicrobial activity as seen in the case of compound B4 (6-fluoro). The compounds substituted with hydroxyl group (B5) exhibited good antioxidant activity.

Exploration of the Antimicrobial Effects of Benzothiazolylthiazolidin-4-One and In Silico Mechanistic Investigation

“…We have replaced 6-trifluoromethoxy substituent of benzothiazole ring first by 6-CN, 6-Ad, 4-Me-6-Ad and after by 4-OCH3, and 6-Cl keeping the same substitution at position 4 of benzene ring mostly for 6-Cl, 4-OMe and in some cases of 6-CN (Figure 2). Thus, we synthesized 2-(2-(substituted phenyl)-4-oxothiazolidin-3yl)benzo [d] (15)(16)(17)(18)(19).…”

“…In an attempt to improve more the antibacterial activity, we decided to introduce in position 4 and 6 of benzothiazole ring methoxy (10-14) and chloro (15)(16)(17)(18)(19) substituents, respectively.…”

“…Replacement of hydroxyl by methoxy group led to a little less potent compound 18. Introduction of nitro or fluoro group at 4-position of benzene ring derivatives (16) or (15) had negative influence on antifungal activity, the latter being the less active compound. In case of compounds with methoxy group at position 4 of benzothiazole moiety, the presence of fluoro-and nitro substituents at position 4 of benzene ring demonstrated the same influence on antifungal activity, as compounds 15-19.…”

“…It is worth mentioning that benzothiazole is a privileged heterocyclic scaffold with multiple applications and tremendous range of pharmacological activity. Benzothiazoles are recognized for their anti-inflammatory [ 12 , 13 , 14 ], antimicrobial [ 15 , 16 , 17 , 18 , 19 ], anesthetic [ 20 ], anticancer [ 21 , 22 , 23 ], anti-viral [ 24 , 25 , 26 ], analgesic [ 13 , 14 ], antipyretic [ 27 ], antidiabetic [ 28 , 29 , 30 ], antioxidant [ 12 , 16 , 20 , 21 , 31 ], carbonic anhydrize inhibitory [ 26 , 32 , 33 ], anticonvulsive [ 34 , 35 ], antifungal [ 33 , 36 , 37 ] and many other [ 38 , 39 ] activities. Additionally, the benzothiazole scaffold is present in three FDA approved drugs ( Figure 1 ).…”

Experimental and In Silico Evaluation of New Heteroaryl Benzothiazole Derivatives as Antimicrobial Agents

“…Benzothiazoles and its derivatives attracted the interest of medicinal chemists because of their extensive variety of pharmacological properties, including anti-inflammatory [ 1 , 2 , 3 ], antimicrobial [ 4 , 5 , 6 , 7 ], anticancer [ 8 , 9 , 10 ], antitubercular [ 11 , 12 ], antidiabetic [ 13 ], antioxidant [ 14 , 15 ], antiviral [ 16 , 17 , 18 ], antileishmanial [ 19 ], and others [ 20 , 21 ].…”