Novel Protective Group in [beta]-Lactam Chemistry: 3-Phenoxy-4-phenyl-N-[[alpha]-(phenylthio)benzyl]azetidin-2-one

3-Phenoxy-4-phenyl-1-[phenyl(phenylthio)methyl]azetidin-2-one, C₂₈H₂₃NO₂S, with a novel protective group was prepared from thiophenol. The single-crystal analysis of the compound reveals that the H atoms at C2 and C3 of the [beta]-lactam ring are in the cis configuration. The relative configuration at the C2, C3 and C10 chiral centres are established as S, R and R, respectively. The phenoxy and phenyl substituents at C2 and C3 are at an angle of 120.6 (3)°, while the benzyl and thiophenyl rings attached to the N atom of the [beta]-lactam ring are at an angle of 4.3 (2)° with respect to one another. The central [beta]-lactam ring is bent, with a mean value of 4.3 (2)°.

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