Re2O7-catalyzed formal [3 + 2] cycloaddition for diverse naphtho[1,2-b]furan-3-carboxamides and their biological evaluation.

Diverse naphtho[1,2-b]furan-3-carboxamide derivatives 12a-12q were synthesized in high yield via the novel Re2O7-catalyzed formal [3 + 2] cycloaddition of 1,4-naphthoquinones with β-ketoamides as the key step. This methodology offers several advantages, such as environmentally benign character, the use of a mild catalyst, high yields, and ease of handling. The synthesized compounds were screened for their tyrosinase inhibitory, antioxidant, and antibacterial activities.

Anti-tyrosinase, antioxidant, and antibacterial activities of novel 5-hydroxy-4-acetyl-2,3-dihydronaphtho[1,2-b]furans.

Novel 5-hydroxy-4-acetyl-2,3-dihydronaphtho[1,2-b]furans (7a-k) were synthesized using ceric ammonium nitrate (CAN)-catalyzed formal [3 + 2] cycloaddition. Synthesized compounds were evaluated for their tyrosinase inhibitory, antioxidant, and antibacterial activities. A modified spectrophotometric method using l-DOPA as substrate was used to determine tyrosinase inhibitory activities, and a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay was used to evaluate antioxidant properties.

Preparation of Au and Ag nanoparticles using Artemisia annua and their in vitro antibacterial and tyrosinase inhibitory activities.

This work describes a plant-mediated approach to the preparation of metal nanoparticles using leaf extract of Artemisia annua (A. annua), an ethno-medicinal plant widely found in Asia, which was used as reducing and stabilizing agent. A.

Microwave-assisted synthesis of diverse pyrrolo[3,4-c]quinoline-1,3-diones and their antibacterial activities.

With the aim of developing a general and practical method for library production, a novel and efficient two-phase microwave-assisted cascade reaction between isatins and β-ketoamides in [Bmim]BF4/toluene was developed for the synthesis of pyrrolo[3,4-c]quinoline-1,3-diones. The features of this methodology are, the use of microwave-assisted rapid synthesis, mild reaction conditions, high yields, operational simplicity, facile product separation, and recyclability. Furthermore, the antibacterial activities of the pyrrolo[3,4-c]quinoline-1,3-dione derivatives produced were evaluated against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Enterobacter aerogenes) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus).

Synthesis of novel and diverse mollugin analogues and their antibacterial and antioxidant activities.

Novel and diverse mollugin analogues (1-12) were synthesized using PhB(OH)2/AcOH-mediated electrocyclization reaction as a key step. The newly synthesized compounds were screened for antioxidant and antibacterial activities. Compounds 1, 2, 5, 6, 8, and 10-12 showed high antioxidant activities in DPPH inhibition (IC50=0.