A straightforward approach to 2-azetidinones from imines and carboxylic acids using dimethyl sulfoxide and acetic anhydride

Dicarboxylic Acid Monoesters in β- and δ-Lactam Synthesis

A N-(2-methoxy-2-oxoethyl)-N-(phenylsulfonyl)glycine monomethyl ester of the respective dicarboxylic acid was involved in a reaction with imines promoted by acetic anhydride at an elevated temperature. Instead of the initially expected δ-lactam products of the Castagnoli–Cushman-type reaction, medicinally important 3-amino-2-azetidinones were obtained as the result of cyclization, involving a methylene group adjacent to an acid moiety. In contrast, replacing alcohol residue with hexafluoroisopropyl in the same substrate made another methylene group (adjacent to the ester moiety) more reactive to furnishing the desired δ-lactam in the Castagnoli–Cushman fashion.

Anticancer activity and evaluation of apoptotic genes expression of 2-azetidinones containing anthraquinone moiety

Nowadays, one of the principal causes of death in the world is cancer. A series of 2-azetidinones containing anthraquinone moiety with various substituents were synthesized using [2 + 2] ketene-imine cycloaddition (Staudinger ketene-imine cycloaddition), and their cytotoxicity against some human cancer and normal cell lines was evaluated. Some of these hybrid compounds showed moderate to significant cytotoxicity against breast carcinoma (MCF7), colon carcinoma (HCT116), prostate carcinoma (PC3), and neuroblastoma (SKNMC) cell lines via MTT assay. Surprisingly, hybrid 4gh with the best anticancer activity demonstrated very good antibacterial and antifungal activities. This compound was selected to study to test on human fibroblast (Hu02) normal cell and comparison with doxorubicin. While 2-azetidinone 4gh represented similar cytotoxicity against cancer cell lines compared to doxorubicin, the 2-azetidinone demonstrated lower cytotoxicity against human fibroblast (Hu02) than doxorubicin. Further real-time PCR investigation displayed the expression of Bcl-xl, KI-67, TPX2 and BAX genes were significantly increased or decreased as desired in the cancer cell lines studied by treatment with doxorubicin or 2-azetidinone-anthraquinone 4gh. Molecular docking studies represented that hybrid 4gh strongly fitted the active site of topoisomerase II (PDB 4G0V) with hydrogen bond and hydrophobic interactions.

The facile and efficient synthesis of novel monocyclic cis-β-lactam conjugates with a 1-methyl-1H-imidazole-2-thiol nucleus

We developed a facile and efficient synthesis of novel monocyclic cis-β-lactam conjugates with a 1-methyl-1H-imidazole-2-thiol nucleus through a ketene-imine [2+2] cycloaddition reaction of acyl chloride and different Schiff bases.

Discovery of BMS-986235/LAR-1219: A Potent Formyl Peptide Receptor 2 (FPR2) Selective Agonist for the Prevention of Heart Failure

Formyl peptide receptor 2 (FPR2) agonists can stimulate resolution of inflammation and may have utility for treatment of diseases caused by chronic inflammation, including heart failure. We report the discovery of a potent and selective FPR2 agonist and its evaluation in a mouse heart failure model. A simple linear urea with moderate agonist activity served as the starting point for optimization. Introduction of a pyrrolidinone core accessed a rigid conformation that produced potent FPR2 and FPR1 agonists. Optimization of lactam substituents led to the discovery of the FPR2 selective agonist 13c, BMS-986235/LAR-1219. In cellular assays 13c inhibited neutrophil chemotaxis and stimulated macrophage phagocytosis, key end points to promote resolution of inflammation. Cardiac structure and functional improvements were observed in a mouse heart failure model following treatment with BMS-986235/LAR-1219.

CuFe2O4 nanoparticles catalyze the reaction of alkynes and nitrones for the synthesis of 2-azetidinones

The reaction of alkynes and nitrones (Kinugasa reaction) in the presence of magnetically recoverable CuFe₂O₄ nanoparticles as a highly efficient heterogeneous catalyst under a mild condition for the synthesis of various 2-azetidinones was reported.

Synthesis of 1,3-diaryl-spiro[azetidine-2,3′-indoline]-2′,4-dionesviathe Staudinger reaction:cis- ortrans-diastereoselectivity with different addition modes

A new synthetic approach for realizing biologically relevant bis-aryl spiro[azetidine-2,3′-indoline]-2′,4-diones was developed based on Staudinger ketene–imine cycloaddition through the one-pot reaction of substituted acetic acids and Schiff bases in the presence of oxalyl chloride and an organic base. A series of [azetidine-2,3′-indoline]-2′,4-diones were synthesized using this method. For comparison, the same compounds were obtained using a known technique, where ketene is generated from pre-synthesized acyl chloride. It was shown that the use of oxalyl chloride for ketene generation in the one-pot reaction at room temperature allows for the reversal of the diastereoselectivity of spiro-lactam formation, unlike previously described procedures.

Two experimental techniques of the ketene–imine Staudinger reaction allowed different diastereomers of spiro-indolinone-β-lactams to be obtained.

Synthesis, in vitro biological evaluation and in silico molecular docking studies of novel β-lactam-anthraquinone hybrids

Schiff bases from 2-aminoanthraquinone have been prepared by reaction with aldehydes and used to prepare novel β-lactam-anthraquinone hybrids via [2+2] ketene-imine cycloaddition (Staudinger reaction) reaction. In vitro antibacterial studies of all synthesized compound were carried out against three gram-positive strains Staphylococcus aureus (Methicillin-resistant strain), Enterococcus faecium (Vancomycin-resistant strain) and Bacillus subtilis, and two gram-negative strains Escherichia coli and Pseudomonas aeruginosa. These compounds were further evaluated for their in vitro antifungal activity against Candida albicans, Aspergillus niger and Trichophyton mentagrophytes. Hybrid compounds showed moderate to excellent antibacterial and antifungal activities. Surprisingly, among the tested compounds, some of them revealed equal antibacterial and antifungal properties and even better than standards. In addition, results demonstrated that the new hybrids are very promising antibacterial agents against resistant strains. Also molecular docking studies were carried out by Autodoc software. Penicillin-binding protein 2a (PDB ID: 1VQQ) from methicillin-resistant Staphylococcus aureus strain used as a target which good binding interactions were observed.

Application of magnetic Fe3O4nanoparticles as a reusable heterogeneous catalyst in the synthesis of β-lactams containing amino groups

The catalytic activity of magnetic Fe₃O₄nanoparticles to promote the reduction of β-lactams containing nitroaryl groups to β-lactams containing aminoaryl groups in ethanol was reported. This methodology is convenient and green.

Synthetic Approaches toward Monocyclic 3-Amino-β-lactams

Due to the emerging resistance against classical β-lactam-based antibiotics, a growing number of bacterial infections has become harder to treat. This alarming tendency necessitates continued research on novel antibacterial agents. Many classes of β-lactam antibiotics are characterized by the presence of the 3-aminoazetidin-2-one core, which resembles the natural substrate of the target penicillin-binding proteins. In that respect, this Review summarizes the different synthetic pathways toward this key structure for the development of new antibacterial agents. The most extensively applied methods for 3-amino-β-lactam ring formation are discussed, in addition to a few less common strategies. Moreover, approaches to introduce the 3-amino substituent after ring formation are also covered.

Facile Synthesis of β-Lactam Derivatives by the Staudinger Reaction Using 3,6-Dichlorotetrazine

A versatile and convenient method for synthesis of β-lactams using 3,6-dichlorotetrazine as an acid activator in the ketene–imine cycloaddition is reported. Monocyclic and spirocyclic β-lactams are obtained in good to excellent yields. Easy purification of the products can be performed by aqueous workup and then crystallisation from ethyl acetate.

Silphos as an efficient heterogeneous reagent for the synthesis of 2-azetidinones

This report provides a description of an efficient and simple procedure for the synthesis of 2-azetidinones