Facile synthesis of novel monocyclic trans- and cis-3-oxy/thio/seleno-4-pyrazolyl-β-lactams

Abstract

A facile synthesis of novel monocyclic trans- and cis-3-oxy/thio/seleno-4-pyrazolyl-β-lactams (5, 6) is described. The reaction of 2-methoxy/phenoxy/benzyl/phenylthio/seleno ethanoic acids or acetoxyacetyl chloride 4 with pyrazolyl substituted Schiff's bases 3a-d using POCl3 and Et3N in refluxing toluene furnished β-lactams (5, 6). These synthesized β-lactams have been characterized by spectroscopic techniques viz. NMR (1H, 13C and 77Se), FT-IR, mass spectrometry (EI-MS and HRMS) and elemental analysis. Single crystal X-ray crystallographic study of trans-1-(4′-methoxyphenyl)-3-methoxy-4-(5′-chloro-3′-methyl-1′-phenyl-1H-pyrazol-4′-yl)azetidin-2-one 5p has confirmed the molecular structure and the stereochemical outcome. The cis or trans configuration of β-lactams (5, 6) was assigned with respect to position of C3-H and C4-H.