The reaction sequence for different title compounds 9(a–n) was accomplished by a synthetic procedure as shown in (Scheme 1). All the synthesized compounds were characterized by IR, NMR, and mass spectral data. The starting materials substituted phenyl benzoate analogues (3a–b) were synthesized by benzoylation of o-cresol (1) with corresponding benzoyl chlorides 2(a–b) using 10% sodium hydroxide solution. Fries rearrangement of compounds 3(a–b), was carried out under neat conditions, using anhydrous aluminium chloride as a catalyst to afford hydroxy benzophenones 4(a–b). The compounds 4(a–b) on etherification with ethyl chloroacetate using dry acetone as a solvent gave substituted ethyl 2-(4-benzoylphenoxy) acetates 5(a–b). The compounds 5(a–b) in ethanol were treated with hydrazine hydrate dropwise, with continuous stirring for two hours to achieve substituted 4-benzoyl-phenoxy aceto hydrazides 6(a–b). Further, the compounds 6(a–b) in absolute ethanol were treated with substituted aldehydes 7(a–g) with a catalytic amount of acetic acid and refluxed for 8–10 h to obtain substituted 2-(4-benzoyl-2-methylphenoxy)-N-(2-benzylidene) acetohydrazides 8(a–n). Finally, the compounds 8(a–n) and triethyl amine as catalyst in dioxane were cooled and stirred. To this well-stirred cold solution, chloroacetyl chloride was added dropwise within a period of 20 min and stirring was continued for an additional 3 h to furnish the title compounds substituted 2-(4-benzoyl-2-methyl-phenoxy)-N-(3-chloro-2-oxo-4-phenyl-azetidin-1-yl)-acetamides 9(a–n). Among 3(a–b) the spectrum of compound (3a), is selected as a representative example. The formation of this compound was confirmed by the appearance of the carbonyl stretching band for the ester group at 1715 cm−1 in the IR spectrum and the appearance of nine aromatic protons between 7.0 and 7.8 ppm in the proton NMR spectrum. The mass spectrum of compound (3a) gave a significant stable (M + 1) peak at m/z 213 which is also evident for the formation of compound (3a). Further, the spectrum of compound (4a), was considered as a representative example of the series (4a–b). The IR spectrum showed the disappearance of the carbonyl stretching band of the ester group of compound (3a). The proton NMR spectrum of compound (4a) was established by the appearance of the OH stretching band at 3510–3600 cm−1, and the appearance of a broad singlet for the OH proton at δ 12.0 ppm and a decrease in one aromatic proton between 6.71 and 7.70 ppm. The mass spectrum of compound (4a) offered a significant stable (M + 1) peak at m/z 213 which is considered as additional evidence for the formation of this compound. Subsequently, compound (5a) was taken as a representative example for the 5(a–b) series, which was confirmed by the appearance of the carbonyl stretching band for the ester group at 1760 cm−1 in the IR absorption spectrum. Moreover, it was confirmed by the disappearance of a broad singlet peak for the OH proton of compound (4a) and the appearance of a triplet and quartet for CH3 and CH2 protons at δ 2.31 and 4.15 ppm, respectively by proton NMR observation. Furthermore, the mass spectrum gave a significant stable (M + 1) peak at m/z 299 which clearly confirmed the formation of the compound (5a). The synthesis of compound (6a) was confirmed by the appearance of NH and NH2 stretching bands in the range between 3120–3220 cm−1 and carbonyl stretching band of amide at 1670 cm−1 in the IR spectrum. It was also confirmed by the proton NMR spectrum with the appearance of singlet amide −NH peak at δ 9.55 ppm and singlet NH2 peak around δ ppm and by the disappearance of triplet and quartet peaks for CH3 and CH2 protons respectively of compound (5a). The mass spectrum of this compound gave a significant stable (M + 1) peak at m/z 286 which also affirmed the formation of product (6a). Likewise, the structure of the compound (8a) was confirmed by the disappearance of NH2 band of compound (6a) and the appearance of C = N stretching band at 1630 cm−1 in the IR spectrum. Furthermore, in proton NMR, the appearance of a singlet peak of HC = N proton at δ 8.45 ppm, and an increase in four aromatic protons, confirmed the formation of the product (8a). The mass spectrum of compound (8a) gave two significant stable (M+) peak at m/z 407 and (M + 2) peak at 409 which also proves the formation of the compound (8a). Finally, the spectrum of the compound (9a) was considered as a representative example for the title compounds series 9(a–n). This was supported by the disappearance of C = N stretching band of the compound (8a) and by the appearance of the carbonyl stretching band of azetidinone ring at 1655 cm−1 in the IR spectrum. It was also proved by the NMR spectrum by the disappearance of singlet proton peak of HC = N and appearance of N-CH proton singlet peak at δ 5.45 ppm and singlet peak of Cl-CH at 5.6 ppm. The mass spectrum of compound (9a) gave two significant peaks of m/z 483 (M+) and 485 (M + 2), which also revealed the formation of the compound (9a).