Synthesis and characterization of novel trans-3-benzyl/(diphenyl)methyl/naphthyl seleno substituted monocyclic β-lactams: X-ray structure of trans-1-(4′-methoxyphenyl)-3-(diphenyl)methylseleno-4-(4′-methoxyphenyl)azetidin-2-one

Several novel trans-3-benzyl/(diphenyl)methyl/naphthylseleno substituted monocyclic β-lactams (5–7) have been synthesized in high yields. The reaction scheme inolves [2 + 2] cycloaddition (Staudinger) reaction between suitably substituted imines 4(a–h) and ketenes (B) accessed from 2-benzyl/(diphenyl)methyl/naphthylselenoethanoic acids (1–3) using POCl3 and triethylamine in refluxing toluene. Characterization of these newly synthesized seleno substituted β-lactams has been performed by various spectroscopic techniques viz. NMR (1H, 13C and 77Se), FTIR, mass spectrometry and elemental analysis. The molecular structure of trans-1-(4′-methoxyphenyl)-3-(diphenyl)methylseleno-4-(4′-methoxyphenyl)azetidin-2-one (6b) has also been established with the help of single crystal X-ray analysis.