It is an unsubstituted four membered lactam.It is the fundamental building block of β-lactam antibiotics. X-ray photoelectron spectra of 2-azetidinone was investigated.It undergoes hydrolysis with aqueous alkali to yield β-alanine.It was used in synthesis of optically pure densely functionalized γ-lactams. It is an unsubstituted four membered lactam.It is the fundamental building block of β-lactam antibiotics. X-ray photoelectron spectra of 2-azetidinone was investigated.It undergoes hydrolysis with aqueous alkali to yield β-alanine. It was used in synthesis of optically pure densely functionalized γ-lactams.