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3-Butadienyl-β-lactams are useful organic synthon which have efficiently been explored for the synthesis of a variety of heterocyclic systems. The present review compiles the various reports on the...

An efficient protocol for the stereoselective synthesis of pyrazolo[5,1-b]thiazole-3-carboxylate tethered β-lactam conjugates 8a–j from novel pyrazolo [5,1-b]thiazole-3-carboxylate substituted Schiff’s bases 6a–f is reported here. The reaction between various ketene precursors and novel Schiff’s bases 6a–f afforded exclusive formation of trans-β-lactams 8a–j. The substrate scope of this approach was investigated extensively by varying different groups (R, Z). All the novel compounds were characterized using various spectroscopic techniques, such as FT-IR, 1H NMR, 13C NMR, elemental analysis, 13C NMR (DEPT-135), and mass spectrometry in representative cases. Single crystal X-ray crystallographic study of trans-ethyl 7-(1-(4-methoxyphenyl)-4-oxo-3-phenoxyazetidin-2-yl)-6-methyl-2-(methylthio)pyrazolo[5,1-b]thiazole-3-carboxylate 8a has confirmed the molecular structure and the stereochemical outcome. To the best of our knowledge, the synthesis of such types of Schiff’s bases and β-lactam conjugates has not been reported so far.

A series of β-lactams containing the ferrocene moiety were synthesized through the Staudinger reaction between ferrocenylketene generated by the thermal Wolff rearrangement of the corresponding dia...

Stereoselective synthesis of novel monocyclic trans-3-halogenated-4-pyrazolyl-β-lactams 5 is described. The reaction of ketene derived from α-bromo/chloroethanoic acids 4 using POCl3 and Et3N with ...

A short and efficient protocol for the synthesis of β-lactam containing α-hydroxy phosphonate esters using inexpensive catalysts such as tartaric acid and fumaric acid is described.

A series of C3-position adamantyl-substituted β-lactams were synthesized via uncatalyzed Staudinger reaction between adamantylketene generated by thermal Wolff rearrangement of the corresponding diazo ketone and various imines. The stereochemical outcome of the reaction was mainly the formation of trans-products, a result attributed to a two-step mechanism leading to the most stable products.

In this paper, an improved method for the thionation of β-lactams is described. Using a solid-supported P2S5 reagent and heating under reflux conditions, β-thiolactams were obtained in good to excellent yields. Also the reaction time reduced significantly compared with that achieved under the more conventional method using P2S5 alone. Furthermore, inexpensive and easily available starting materials simple reaction conditions and a simple purification process are some other advantages of this method.

Thiocarbonyldiimidazole has been found to be an efficient acid activator for the synthesis of β-lactams by ketene-imine cycloaddition at room temperature. The experimental procedure is simple and results in excellent yields of the products. All products were characterized by spectral data and elemental analyses.

We report in this article the design and calculated molecular properties of 18 new mono-cyclic β-lactams 4–21, on the basis of one hypothetical antibacterial pharmacophore structure designed to interact with both of Gram-positive bacteria and Gram-negative bacteria. The in vitro biological evaluation of these compounds allowed us to point out new potential non-nucleoside hits, with MIC values in the range of 2–8 μg/mL active against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. A correlation structure/antibacterial activities relationship of these monocyclic β-lactams is described. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Silica gel–supported ceric ammonium nitrate (CAN-SiO 2 ) has been found to be an effective reagent for the solid–solid phase and solvent-free N-dearylation of β-lactams. The results have been compared with CAN alone in solution and solid–solid phase.

An efficient and exclusive synthesis of the tricyclic azeto[2,1-d][1,5]benzothiazepine ring system has been developed. By use of microwave irradiation in the presence of basic alumina, the reaction time has been brought down from hours to minutes with improved yields in comparison to conventional heating. Antimicrobial screening of the synthesized compounds has shown promising activity.

Five N‐(4‐methoxyphenyl)‐ and five N‐(4‐ethoxyphenyl)‐β‐lactams were prepared by ketene‐imine [2+2] cycloaddition (Staudinger reaction). Then these 2‐azetidinones were N‐dearylated by grinding together with ceric ammonium nitrate without hazardous solvents in good to excellent yields. The solid‐solid phase N‐dearylation is easier, simpler, and more efficient than the general method in solution. The pure N‐unsubstituted β‐lactams obtained by a nontedious workup and without further purification.

Penicillins have been widely used in veterinary medicine for more than 30 years and today still form the most important group of antibiotics. Since there is a potential impact of their residues in animal derived food on consumers' health, their monitoring is of paramount importance. This review focuses on residue analysis of penicillins in food products of animal origin by high performance liquid chromatography. Emphasis is given to confirmatory methods since these comprise useful tools to regulatory agencies and identifications based on these methods can be used in support of regulatory action. Sample preparation for analyte extraction and cleanup have been also discussed.

Catalyzed by ytterbium(III) triflate [Yb(OTf)3], β‐lactams were stereoselectively synthesized from imines and acetyl chlorides in ionic liquid under mild conditions. The ionic liquid and catalyst could be recycled and reused as opposed to traditional solvent–catalyst systems.

Synthetic routes toward the synthesis of some novel 1-(2,3,4-tri-O-acetyl-alpha-L-arabinopyranosyl)-azetidin-2-ones are described. Antimicrobial screening of three selected compounds revealed their activity against Bacillus subtilis and Escherichia coli

α‐Cyano and α‐chloro β‐lactams are obtained in a one‐step reaction at a temperature of less than −78°C by condensation of imines with ester enolates derived from ethyl α‐cyano and α‐chloro acetates.

β‐Lactams 2 have been synthesized through a convenient use of POCl3 via cyclodehydration of β‐amino acids 1.

Beta-lactamases of Enterobacteriaceae are the most important mechanism of resistance against beta-lactam drugs. Two types of beta-lactamases can confer resistance against 3rd generation cephalosporins. Chromosomally mediated beta-lactamases are inducible and are not inhibited by clavulanic acid. Resistance due to these enzymes is non-transferable. The 2nd type of enzyme is plasmid-mediated beta-lactamases, which are inhibited by clavulanic acid. These enzymes are more important clinically as these can be transferred between various species of Enterobacteriaceae. These enzymes are called extended-spectrum beta-lactamases (ESBLs). ESBL-producing Enterobacteriaceae have been responsible for numerous outbreaks of infection throughout the world and pose challenging infection control issues. Antibacterial choice is often complicated by multi-resistance. ESBLs can confer resistance against all beta-lactam drugs except carbapenems and cephamycins. Nursing home patients may be an important reservoir of ESBL-containing multiple antibiotic-resistant organisms. Use of broad-spectrum oral antibiotics and probably poor infection control practices may facilitate spread of this plasmid-mediated resistance. In addition to known populations at risk, ambulatory patients with chronic conditions represent another patient population that may harbor ESBL-producing organisms. Various methods can be used for detection of ESBLs in the laboratory. These tests include double disc diffusion test, Vitek ESBL test, E Tests, MIC Determination, genetic method, and isoelectric focusing (IEF).

Chiral formates derived from propane-1,2-diol, 1,2- O -isopropylidene- f - D -xylo- and f - D -gluco-furanoses were subjected to treatment with cyclopentadienyl [tris(trimethylsilylmethyl)] titanium (IV). A mixture of the corresponding ( E )- and ( Z )- g -silylvinyl ethers were obtained with predominance of the former. It was found that in contrast to ( Z )-vinyl ethers, which give g -lactams with chlorosulfonyl isocyanate, the ( E )-vinyl ethers gave unstable cycloadducts which undergo rapid elimination reaction leading to ( E )- f , g -unsaturated amides.

N(4-hydroxycyclohexyl)-3-mercapto/cyano-4-arylazetidine-2-one were synthesised from N-(4-hydroxycyclohexyl)-arylaldimine by reacting with ethyl α-mercapto/α-cyanoacetate on basic alumina under microwaves, wherein not only the reaction time has been brought down from hours to minutes in comparison to conventional heating but also with improved yield.

Image analysis is a modern and fast-developing method for various kinds of investigations. The strongest benefits of image analysis are versatility and rapidity. The method is typically used togeth...

La reponse des coques gram positifs aux cephalosporines de troisieme generation chez les patients neutropeniques febriles n'est pas optimale. Nous avons conduit une etude retrospective pour evaluer l'efficacite et la securite de l'association ceftazidime plus penicilline (C+P) versus ceftazidime plus vancomycine (C+V). Nous avons inclus 64 patients admis dans le service d'Hematologie pour auto- ou allogreffe. Trente six patients ont ete traites par C+V et 28 patients par C+P. Un succes de l'antibiotherapie initiale a ete observe dans 78% des patients dans le groupe C+V et dans 57% dans le groupe C+P (p = 0,5). Tous les patients etaient en vie au jour 3. Dans chaque groupe un patient est decede d'infection. Nous avons conclu que la combinaison de C+P est aussi efficace et aussi sure que la combinaison C+V chez les patients neutropeniques febriles. La mortalite et la morbidite etaient identiques dans chaque groupe et le cout-efficacite etait en faveur de la combinaison C+P.

Considerable information on the pharmacodynamics of betalactams has accumulated throughout the past 20 years demonstrating a time-dependent killing and some pharmacodynamic differences in the type of activity in-vitro and in animal models that should have clinical significance. Unfortunately few clinical studies have directly examined the effects of different dosages that might be predicted to result in failure or success of the outcome, particularly in serious sepsis. Thus on the basis of a long preclinical and clinical experience we propose a pharmacodynamic classification of betalactam antibiotics. Three classes are delineated by the extent of PBP pattern saturation, biomass increase, PAE length and initial killing power.

Two rare cases of Gemella morbillorum endocarditis, caused by a strain resistant to penicillin and gentamicin are reported. G. morbillorum is usually sensitive to beta-lactams and aminoglycosides. The present 2 cases raise concern that appropriate prophylaxis and empirical treatment may be more complicated than believed in the past.

An efficient method based, on the acid chloride-imine reaction, is reported for the preparation of 1,3-disubstituted β-lactams in good yield and with high selectivity.

Neodymium(III) and samarium(III) complexes of type [Ln(Lac)3Cl3] (Lac = β-lactams or 2-azetidinones; Ln = Nd(III) or Sm(III)) have been synthesized and characterized on the basis of elemental analyses, conductance, magnetic moment and spectral (electronic and infrared) data. The thermal behaviour of these complexes has also been studied by TGA and DTA techniques. The antifungal and antiviral activities of the ligands and the complexes were also investigated.

Cyclization of L-aspartic acid to (S)-4-benzyloxycarbonyl-2-azetidinone followed by transesterification of this compound in the presence of titanium (IV) tetrabutoxide proved to be an exceedingly efficient method of general application for the preparation of (S)-4-alkoxycarbonyl-β-lactams.

The synthesis of β-lactams was carried out by N-arylpropionamide cyclisation in a mixture of N,N-dimethylformamide and anhydrous sodium carbonate under nitrogen atmosphere with 50 to 90% yield.

Isocyanates derived from uretanes 4, s and benzamides 6, 7 react with di-O-benzyl-D-arabinal 3 under 12 kbar pressure to afford the corresponding cycloadducts with high stereoselectivity. Alkoxycarbonyl isocyanates 4 and 5 from [2 + 2]cycloadducts almost exclusively, where benzoyl iSocyanates produce 1:1 mixtures of [2 + 21 and [4 + 2]cycloadducts.

This paper concerns a preparative method of β-lactam formation using N-[(3R)-3, 7-dimethyl-6-octen-1-ylidene]-N-cyclohexylamine [I] derived from 1-citronellal. The reaction of [I] with ethyl bromoacetate in the presence of zinc gave a β-lactam 4-[(2R)-2, 6-dimethyl-5-hepten-1-yl]-(1-cyclohexyl)azetidin-2-one [II]. Instead of β-lactam for-mation, N-[(3R)-3, 7-dimethyl-1, 6-octadien-1-yl]-N-cyclohexyl-2-methylpropionamide[III] was obtained from the reaction of [I] with isobutyryl chloride and triethylamine.

β-Lactams, derived via the cycloaddition of chlorosulfonyl isocyanate to alkenes, undergo thermal rearrangement at room temperature to afford γ-lactams.

α-Methylene-β-lactams are prepared by a Peterson olefination reaction. These substrates can be epoxidized with MCPBA to give the title dispiro-epoxy-β-lactams. Under the influence of boron trifiuoride, these substrates rearrange to spiro-3-ketolactams.

4-Thiazolidinones (10) and β-lactams (12) of anticipated biological activities were prepared via reaction of N[4-(arylideneamino)benzoyl] N,N′-dicyclohexylureas (8) with mercaptoacetic acid and chloroacetyl chloride, respectively. The title compound, N(4-aminobenzoyl)-N,N′ -dicyclohexylurea (4), was obtained via interaction of 4-aminobenzoic acid (2) with dicyclohexylcarbodiimide (1). Condensation of (4) with aromatic aldehydes afforded the corresponding arylidene derivatives (8) in good yield. Biological screening of selected products was done against some strains of bacteria.

Oral therapy options for pyelonephritis caused by ESBL producing E. coli are limited. We describe a woman with relapsing pyelonephritis due to a CTX-M ESBL E. coli who was cured with a prolonged course of pivmecillinam. This suggests pivmecillinam may be effective treatment for selected patients with pyelonephritis with these organisms.

2-Acyl-3-oxo-4,5-benzo-1,2-thiazoline 1,1-dioxide (3) provides good yield routes to monocyclic 3-lactams (6) and tricyclic β-lactams (7) from a variety of imines (4) and 1-substituted-3,4-dihydroisoquinolines (5).

In 1966 Bose and co-workers2 introduced azidoacetyl chloride as a valuable reagent for β-lactam synthesis by the “acid chloride-imine method.”3 The azido group serves as a crypto amino function for further elaboration of the penicillin and cephalosporin side chain. The use of this reagent in β-lactam chemistry has proved very fruitful; the synthesis of trans penicillin V methyl ester,4 cephalosporins,5 penicillin,5 4-mercapto-2-azetidinones,6 and other β-lactams have been achieved in various laboratories through the intermediacy of this reagent. Azidoacetyl chloride, like other azido compounds, however, tends to decompose with explosive violence if rigorous precautions are not observed. We have been engaged, therefore, in exploring alternative synthetic approaches to β-lactams which would make the use of azidoacetyl chloride unnecessary. In the present communication we wish to report a facile method for the preparation of α-azido-β-lactams and other 3-substituted-2- azetidinones without employing...

Doyle et al1 reported one of the most versatile and reliable methods for generating cis-β-lactams (type III) as intermediates for the formation of 1-carbacephams. It consists in adding azidoacetyl chloride to a mixture of cinnamylidene Schiff bases (type II) and triethylamine in methylene chloride.