Synthesis and antibacterial activity of C4 substituted monobactams

Methodology for Monobactam Diversification: Syntheses and Studies of 4-Thiomethyl Substituted β-Lactams with Activity against Gram-Negative Bacteria, Including Carbapenemase Producing Acinetobacter baumannii

Bromine induced lactamization of vinyl acetohydroxamates facilitated syntheses of monocyclic β-lactams suitable for incorporation of a thiomethyl and extended functionality at the C(4) position. Elaboration of the resulting substituted N-hydroxy-2-azetidinones allowed incorporation of functionalized α-amino substituents appropriate for enhancement of antibiotic activity. Evaluation of antibacterial activity against a panel of Gram-positive and Gram-negative bacteria revealed structure-activity relationships (SAR) and identification of potent new monobactam antibiotics. The corresponding bis-catechol conjugate, 42, has excellent activity against Gram-negative bacteria including carbapenemase and carbacephalosporinase producing strains of Acinetobacter baumannii, which have been listed by the WHO as being of critical concern worldwide.

Pyridone-conjugated monobactam antibiotics with gram-negative activity

Herein we describe the structure-aided design and synthesis of a series of pyridone-conjugated monobactam analogues with in vitro antibacterial activity against clinically relevant Gram-negative species including Pseudomonas aeruginosa , Klebsiella pneumoniae , and Escherichia coli . Rat pharmacokinetic studies with compound 17 demonstrate low clearance and low plasma protein binding. In addition, evidence is provided for a number of analogues suggesting that the siderophore receptors PiuA and PirA play a role in drug uptake in P. aeruginosa strain PAO1.

Novel monobactams utilizing a siderophore uptake mechanism for the treatment of gram-negative infections

Novel siderophore-linked monobactams with in vitro and in vivo anti-microbial activity against MDR Gram-negative pathogens are described.

3,4-Disubstituted azetidinones as selective inhibitors of the cysteine protease cathepsin K. Exploring P3 elements for potency and selectivity

The synthesis of a series of highly potent and selective inhibitors of cathepsin K based on the 3,4-disubstituted azetidin-2-one warhead is reported. A high degree of potency and selectivity was achieved by introducing a basic nitrogen into the distal part of the P3 element of the molecule. Data from kinetic and mass spectrometry experiments are consistent with the interpretation that compounds of this series transiently acylate the sulfhydrile of cathepsin K.

3,4-disubstituted azetidinones as selective inhibitors of the cysteine protease cathepsin K. Exploring P2 elements for selectivity

A novel series of 3,4-disubstituted azetidinones based inhibitors of the cysteine protease cathepsin K (Cat K) has been identified. Although not optimized, some of these compounds show at least 100-fold selectivity against other cathepsins. The use of cyclic moieties as P2 elements has proven to be crucial to achieve a high degree of selectivity.

3-Acylamino-azetidin-2-one as a novel class of cysteine proteases inhibitors

A new class of inhibitors for cysteine proteases cathepsin B, L, K and S is described. These inhibitors are based on the beta-lactam ring designed to interact with the nucleophilic thiol of the cysteine in the active site of cysteine proteases. Some 3-acylamino-azetidin-2-one derivatives showed very potent inhibition activities for cathepsins L, K and S at the nanomolar or subnanomolar IC(50) values.

Design and synthesis of 6-substituted amino-4-oxa-1-azabicyclo[3,2,0]heptan-7-one derivatives as cysteine proteases inhibitors

A series of 6-substituted amino-4-oxa-1-azabicyclo[3,2,0]heptan-7-one compounds was designed and synthesized as a new class of inhibitors for cysteine proteases cathepsins B, L, K, and S. One compound (5S,6S)-6-(N-benzyloxycarbonyl-L-phenylalanyl) amino-4-oxa-1-azabicyclo[3,2,0]heptan-7-one showed excellent cathepsin L and K inhibition activity with IC(50) at a low nanomolar range.