Resistance in Gram-negative bacteria
to β-lactam drugs is
mediated primarily by the expression of β-lactamases, and co-dosing
of β-lactams with a β-lactamase inhibitor (BLI) is a clinically
proven strategy to address resistance. New β-lactamases that
are not impacted by existing BLIs are spreading and creating the need
for development of novel broader spectrum BLIs. IID572 is a novel
broad spectrum BLI of the diazabicyclooctane (DBO) class that is able
to restore the antibacterial activity of piperacillin against piperacillin/tazobactam-resistant
clinical isolates. IID572 is differentiated from other DBOs by its
broad inhibition of β-lactamases and the lack of intrinsic antibacterial
activity.
Targeted antimitotic agents are a promising class of
anticancer
therapies. Herein, we describe the development of a potent and selective
antimitotic Eg5 inhibitor based antibody–drug conjugate (ADC).
Preliminary studies were performed using proprietary Eg5 inhibitors
which were conjugated onto a HER2-targeting antibody using maleimido
caproyl valine-citrulline para-amino benzocarbamate, or MC-VC-PABC
cleavable linker. However, the resulting ADCs lacked antigen-specificity
in vivo, probably from premature release of the payload. Second-generation
ADCs were then developed, using noncleavable linkers, and the resulting
conjugates (ADC-4 and ADC-10) led to in
vivo efficacy in an HER-2 expressing (SK-OV-3ip) mouse xenograft model
while ADC-11 led to in vivo efficacy in an anti-c-KIT
(NCI-H526) mouse xenograft model in a target-dependent manner.
The new potentially best-in-class β-lactamase inhibitor IID572 was discovered by a late-stage functionalization approach. An alternative synthesis was developed to satisfy the short-term material need for toxicological studies in animals. The new synthetic strategy was built on two key features, an intramolecular azomethine ylide [3 + 2] cycloaddition that allowed the efficient formation of molecular complexity from readily available starting materials and an enzymatic resolution that resulted in high optical purity of a key intermediate.
2-Methyl-1-cyclohexanamine
exists in four stereoisomeric forms.
Although it is a simple compound, none of the stereoisomers is readily
available in its pure form. We herein described a crystallization
method identified by a salt screen (diastereomeric salt formation)
allowing the isolation of a single trans enantiomer
from a readily available commercial source consisting of a mixture
of all four stereoisomers.
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