Stereocontrolled facile synthesis and antimicrobial activity of oximes and oxime ethers of diversely substituted bispidines

A small library of diversely substituted 2,4,6,8-tetraaryl-3,7-diazabicyco[3.3.1]nonan-9-ones, their oximes and O-methyloximes were achieved in a stereocontrolled manner by an easiest synthetic strategy as single isomers with high yields. Stereochemistry of all the synthesized compounds was established by their 1D/2D NMR spectral studies, further, witnessed by single-crystal XRD analysis. Accordingly, the compounds exist in a chair-boat conformation with equatorial orientation of the substituents in the chair part and boat-axial orientation in the boat part. Finally, all the synthesized oximes and oxime ethers were evaluated for their in vitro antimicrobial activity against a panel of pathogenic bacteria and fungi, and as a result of the structure–activity correlations, some lead molecules were known for further optimization.

Graphical abstractA small library of diversely substituted bispidines and their oximes/oxime ethers viz, 2,4,6,8-tetraaryl-3,7-diazabicyclo[3.3.1]nonan-9-ones and 2,4,6,8-tetraaryl-3,7-diazabicyclo[3.3.1]nonan-9-one oximes/O-methyloximes were synthesized and unambiguously characterized by 1D/2D NMR and single-crystal XRD data. All the synthesized oximes and oxime ethers were tested against a panel of pathogenic bacteria and fungi for their in vitro antibacterial and antifungal activities.Figure optionsDownload full-size imageDownload as PowerPoint slide