Bacterial biosynthesis of nanosilver: a green catalyst for the synthesis of (amino pyrazolo)-(phenyl)methyl naphth-2-ol derivatives and their antimicrobial potential

Over the past few decades, the use of silver nanoparticles in various fields like medicine, agriculture and the food industry has emerged as an interesting and exciting approach. In addition to these, recently, silver nanoparticles have also demonstrated their catalytic properties in various applications like synthesis of pharmaceutical compounds and natural products. The use of silver nanoparticles as catalysts has gained more importance due to their stability, unique reactivity and recyclability. In the present study, heterogeneous silver nanoparticles, produced from isolated strain Streptomyces sp. RAB 10, were used as catalysts in a three-component reaction of aryl aldehydes, 5-amino-3-methyl pyrazole and β-naphthol for the synthesis of naphthalene-2-derivatives in aqueous media. The synthesized compounds were characterized using 1 H NMR, 13 C NMR, mass spectroscopy and FT-IR. Some of the advantages of the multi-component one-pot protocol used in the study include shorter reaction time, good yield, ease of recoverability and reuse of the silver nanoparticles as catalysts. One of the important features of this methodology is the synthesis of a novel product with two reactive functional groups (hydroxy and free amine), which opens up avenues for the synthesis of a new array of compounds. The biosynthesised AgNPs as well as the naphthalene-2-derivatives exhibited moderate to good anti-microbial activity. Heterogeneous silver nanoparticles produced by Streptomyces sp. RAB 10, were used as bio-catalysts in a three-component reaction in aqueous media.