Expedient Synthesis of Lupulones and Their Derivatization to 2,8-7-Dihydrochromen-7-ones.

A convenient and improved method for the synthesis of beta acids or lupulones, which are known to possess . anti-cancer, anti-inflammatory, anti-oxidative and antimicrobial activity, has been developed successfully. Further derivatization of these complex structures to the corresponding dihydrochromen-7-ones, including the natural product machuone, was realized to simplify their analysis and to confirm their molecular structure.

Synthesis and Penicillin-binding Protein Inhibitory Assessment of Dipeptidic 4-Phenyl-β-lactams from α-Amino Acid-derived Imines.

Monocyclic β-lactams revive the research field on antibiotics, which are threatened by the emergence of resistant bacteria. A six-step synthetic route was developed, providing easy access to new 3-amino-1-carboxymethyl-4-phenyl-β-lactams, of which the penicillin-binding protein (PBP) inhibitory potency was demonstrated biochemically.

α-Unsaturated 3-Amino-1-carboxymethyl-β-lactams as Bacterial PBP Inhibitors: Synthesis and Biochemical Assessment.

Innovative monocyclic β-lactam entities create opportunities in the battle against resistant bacteria because of their PBP acylation potential, intrinsically high β-lactamase stability and compact scaffold. α-Benzylidene-substituted 3-amino-1-carboxymethyl-β-lactams were recently shown to be potent PBP inhibitors and constitute eligible anchor points for synthetic elaboration of the chemical space around the central β-lactam ring. The present study discloses a 12-step synthesis of ten α-arylmethylidenecarboxylates using a microwave-assisted Wittig olefination as the crucial reaction step.

Chemoenzymatic Approach toward the Synthesis of 3--(α/β)-Glucosylated 3-Hydroxy-β-lactams.

Glycosylation significantly alters the biological and physicochemical properties of small molecules. β-Lactam alcohols comprise eligible substrates for such a transformation based on their distinct relevance in the chemical and medicinal community. In this framework, the unprecedented enzymatic glycosylation of the rigid and highly strained four-membered β-lactam azaheterocycle was studied.

In Silico Design and Enantioselective Synthesis of Functionalized Monocyclic 3-Amino-1-carboxymethyl-β-lactams as Inhibitors of Penicillin-Binding Proteins of Resistant Bacteria.

As a complement to the renowned bicyclic β-lactam antibiotics, monocyclic analogues provide a breath of fresh air in the battle against resistant bacteria. In that framework, the present study discloses the in silico design and unprecedented ten-step synthesis of eleven nocardicin-like enantiomerically pure 2-{3-[2-(2-aminothiazol-4-yl)-2-(methoxyimino)acetamido]-2-oxoazetidin-1-yl}acetic acids starting from serine as a readily accessible precursor. The capability of this novel class of monocyclic 3-amino-β-lactams to inhibit penicillin-binding proteins (PBPs) of various (resistant) bacteria was assessed, revealing the potential of α-benzylidenecarboxylates as interesting leads in the pursuit of novel PBP inhibitors.

Exploring the sequence diversity in glycoside hydrolase family 13_18 reveals a novel glucosylglycerol phosphorylase.

In the carbohydrate-active enzyme database, GH13_18 is a family of retaining glycoside phosphorylases that act on α-glucosides. In this work, we explored the functional diversity of this family by comparing distinctive sequence motifs in different branches of its phylogenetic tree. A glycoside phosphorylase from Marinobacter adhaerens HP15 that was predicted to have a novel function was expressed and characterised.

Antibacterial and β-Lactamase Inhibitory Activity of Monocyclic β-Lactams.

Due to the widespread emergence of resistant bacterial strains, an urgent need for the development of new antibacterial agents with novel modes of action has emerged. The discovery of naturally occurring monocyclic β-lactams in the late 1970s, mainly active against aerobic Gram-negative bacteria, has introduced a new approach in the design and development of novel antibacterial β-lactam agents. The main goal was the derivatization of the azetidin-2-one core in order to improve their antibacterial potency, broaden their spectrum of activity, and enhance their β-lactamase stability.

Synthesis of 2-aryl-3-(2-cyanoethyl)aziridines and their chemical and enzymatic hydrolysis towards γ-lactams and γ-lactones.

Trans- and cis-2-aryl-3-(2-cyanoethyl)aziridines, prepared via alkylation of the corresponding 2-aryl-3-(tosyloxymethyl)aziridines with the sodium salt of trimethylsilylacetonitrile, were transformed into variable mixtures of 4-[aryl(alkylamino)methyl]butyrolactones and 5-[aryl(hydroxy)methyl]pyrrolidin-2-ones via KOH-mediated hydrolysis of the cyano group, followed by ring expansion. In addition, next to this chemical approach, enzymatic hydrolysis of the former aziridinyl nitriles by means of a nitrilase was performed as well, interestingly providing a selective route towards the above-mentioned functionalized γ-lactams.