20 INDIAN DRUGS 59 (10) OCTOBER 2022 ORIGINAL RESEARCH ARTICLES DESIGN, SYNTHESIS AND EVALUATION OF N-(BENZO[D]THIAZOL-2-YL)-2-OXO- 2H-CHROMENE-3-CARBOXAMIDE DERIVATIVES AS POTENTIAL ANTIOXIDANT AND ANTIBACTERIAL AGENTS Ranjit V. Gadhave a *, Sachin S. Khade a , Yogita S. Ozarde a , Somdatta Y. Chaudhari b , Arti G. Swami a and Mukesh K. Meena c (Received 17 October 2021) (Accepted 25 May 2022) ABSTRACT This research is focused on designing, synthesis and biological evaluation of a series of coumarin based benzothiazole derivatives. The ligands were identified by docking study for antioxidant and anti- bacterial potential using target proteins PDB:4H1J and PDB:3G75, respectively. The target molecules were synthesized as a series of substituted N-(benzothiazol-2-yl)-2-oxo-chromene-3-carboxamides (7a–h) by condensation of substituted benzo[d]thiazol-2-amines with in situ synthesized substituted 2-oxo-2H-chromene-3-carbonyl chlorides. Infrared spectroscopy and 1 H- nuclear magnetic resonance spectra were used to characterize the synthesized molecules. In vitro antioxidant activity of compounds was evaluated by DPPH and H 2 O 2 radical scavenging assays. Antibacterial potential of compounds was evaluated using well diffusion method against Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853). Among synthesized derivatives, 7a showed good antioxidant potential whereas 7f showed antibacterial activity, which might be employed as lead molecules for future investigation for respective activities. Keywords: Antibacterial, antioxidant, benzothiazole, coumarin, docking, synthesis INTRODUCTION Heterocyclic compounds play a significant role in drug design & discovery. Their derivatization leads to formation of various category drugs, therefore they received considerable attention of many researchers. The incorporation of heterocyclic nucleus can make the molecule more versatile for biological activity and can be converted to drug by lead modification. In the family of heterocyclic compounds, coumarin and benzothiazole played significant role because their derivatives are pharmacologically active and are found in many different categories of drugs. Oxygen-rich heterocyclic coumarin (2H-chromen-2-one) derivatives possess many biological activities like antimalarial 1 , anticancer 1 , monoamino oxidase inhibitor 2 , anti-inflammatory 3 , antioxidant 3,4 , antibacterial 4 , antiviral 5 , analgesic 6 and antimicrobial 7 . Sulfur-rich heterocyclic benzothiazole (1,3-thiazole) derivatives have been reported to exhibit biological activities like antifungal 8 , antimicrobial 9 , antibacterial 10 , antiviral 11 , anticancer 11 , antimalarial 12 , anti- inflammatory 13 and antioxidant 14 . Condensed heterocyclic derivatives showed antioxidant 15 , antimicrobial 16 and anti-inflammatory 17 activities. Cellular damage is caused by reactive oxygen species produced as a result of severe oxidative stress or inadequate antioxidant scavenging activity. Antioxidants slow down the progress of oxidative damage associated with chronic diseases such as cancer, alzheimer, parkinson, inflammation, depression and cataracts, therefore it is essential to design novel antioxidants. The antioxidant potential of heterocyclic compounds can be determined In vitro using DPPH and H 2 O 2 scavenging methods. Similarly, increased bacterial a School of Pharmacy, Dr. Vishwanath Karad MIT World Peace University, Pune-411 038, Maharashtra, India b Department of Pharmaceutical Chemistry, PES’s Modern College of Pharmacy, Nigdi, Pune-411 044, Maharashtra, India c Department of Pharmaceutical Sciences, Mohanlal Sukhadia University, Udaipur-313 001, Rajasthan, India *For Correspondence: E-mail: ranjitgadhave@gmail.com https://doi.org/10.53879/id.59.10.13222