Design and Synthesis of 11H-Xantheno[2,1-c][1,2,5]Selenadiazol-11-One Derivatives as Potent Antimicrobial and Antitubercular Agents

Abstract A series of 11H-xantheno[2,1-c][1,2,5]selenadiazol-11-one derivatives (Va–m) that incorporate a variety of substituents have been synthesized under both conventional heating and microwave irradiation procedures. All these analogs were evaluated for their antimicrobial activity against the Gram-positive bacteria Bacillus subtilis (BS), Staphylococcus aureus (SA), and Staphylococcus epidermidis (SE), against the Gram-negative bacteria Escherichia coli (EC), Pseudomonas aeruginosa (PA), and Klebsiella pneumonia (KP), and against the fungal species Candida albicans (CA), Candida rugosa (CR), Rhizopus oryzae (RO), and Aspergillus niger (AN) and antitubercular activity against MTB H37Rv. Analog, 7,9-dimethoxy-11H-xantheno[2,1-c][1,2,5]selenadiazol-11-one (Vc) was identified as a potent antibacterial agent (MIC[BS] = 2.5 µg/mL, MIC[SA] = 10 µg/mL, MIC[SE] = 2.5 µg/mL, MIC[EC] = 5 µg/mL, MIC[PA] = 10 µg/mL, MIC[KP] = 2.5 µg/mL), and a potent antifungal agent (MIC[CA] = 15 µg/mL, MIC[CR] = 15 µg/mL, MIC[RO] = 10 µg/mL). Another analog, 7,9-dimethyl-11H-xantheno[2,1-c][1,2,5]selenadiazol-11-one (Vj) was also identified as a potent antibacterial agent (MIC[BS] = 2.5 µg/mL, MIC[SA] = 15 µg/mL, MIC[SE] = 2.5 µg/mL, MIC[EC] = 10 µg/mL, MIC[PA] = 15 µg/mL, MIC[KP] = 20 µg/mL), and a potent antifungal agent (MIC[CA] = 2.5 g/mL, MIC[CR] = 10 µg/mL MIC[RO] = 15 µg/mL and MIC[AN] = 10 µg/mL). Based on the MIC data analogs, 7,9-dimethoxy-11H-xantheno[2,1-c][1,2,5]selenadiazol-11-one (Vc) and 7,9-dimethyl-11H-xantheno[2,1-c][1,2,5]selena-diazol-11-one (Vj) were identified as the most potent antimicrobial agents in the series. All these 11H-xantheno[2,1-c][1,2,5]selenadiazol-11-one derivatives (Va–m) were also evaluated for their antitubercular activity against MTB H37Rv. Analogs, 7,9-dimethoxy-11H-xantheno[2,1-c][1,2,5]selenadiazol-11-one (Vc) and 7,9-dimethyl-11H-xantheno[2,1-c][1,2,5]selenadiazol-11-one (Vj) showed MIC of 3.12 µg/mL. These results suggest that analogs, 7,9-dimethoxy-11H-xantheno[2,1-c][1,2,5]selenadiazol-11-one (Vc) and 7,9-dimethyl-11H-xantheno[2,1-c][1,2,5]selenadiazol-11-one (Vj) may be a potential multifunctional ligands for the development of highly effective antimicrobial and antitubercular activity.