Decoration of monocyclic β-lactams with silver nanoparticles

Some monocyclic ß-lactams bearing the amino moiety have been synthesized from b-lactams with a nitro functional group. First of all, the nitro β-lactams (2a-f) were prepared via Staudinger reactions of the corresponding imines with different substituted acetic acids. Then, to have more electron-rich sites which can bind to the electron-deficient silver nanoparticles (AgNPs), they converted to amino β-lactams (3a-f) bearing NH2 group by a reduction process. The cycloadducts were characterized by spectral data, including 1H-NMR, 13C-NMR, IR, mass spectroscopy, elemental analyses, and X-ray crystallography. As the last step, the combination of those amino β-lactams with AgNPs was simply obtained by treatment of them with pre-prepared AgNPs solution. SEM images of β-lactams-AgNPs showed nanoparticles distributed on the surface, and UV–Vis absorption spectra of β-lactams-AgNPs displayed a broad peak in the range of 400-550 nm. These observations confirmed the presence of AgNPs on the surface.