In this study, we report for the first time a brand-new protocol for the multigram-scale synthesis of 5-methyl-6-oxo-1,6-dihydropyridazine-3-carboxylic and 2,8-dimethylimidazo[1,2-b]pyridazine-6-carboxylic acids, without the utilization of metal-complex catalysts. The developed technology for the production of the aforementioned acids is of great importance for two reasons. Firstly, these acids serve as intermediates in the synthesis of risdiplam, the first small-molecule drug approved for the treatment of spinal muscular atrophy. Secondly, they themselves are valuable building blocks right from a broader medicinal chemistry perspective. The synthesis of risdiplam was carried out using a modified synthetic protocol, utilizing the acids indicated above as the key intermediates. The protocols presented in this study enable the production of target compounds with high purity and an acceptable yield.

The escalating global burden of antimicrobial resistance constitutes a public health crisis. The World Health Organization reports that epidemiological models project 10 million deaths attributable to this issue annually by 2050. Among resistant pathogens, metallo-β-lactamase (MBL)-producing organisms represent a clinical challenge, given their consistent association with high rates of morbidity and mortality. This review summarizes effective treatment options against MBL-producing Enterobacterales. In clinical practice, a pragmatic therapeutic decision rule can be applied: when aztreonam–avibactam (ATM–AVI) is accessible and in vitro susceptibility is confirmed, it should be regarded as the preferred targeted regimen for infections caused by MBL-producing Enterobacterales. In settings where ATM–AVI is unavailable, the combination of ceftazidime–avibactam with aztreonam (CAZ–AVI + ATM) remains the treatment of choice, an approach endorsed by current recommendations from the Infectious Diseases Society of America (IDSA) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID). Critical evaluation of the published evidence is essential to inform the selection of optimal therapeutic regimens for affected patients. Novel antimicrobial agents are currently under clinical development and may broaden the therapeutic toolkit in the near future.

Several approaches to the synthesis of risdiplam, a pharmacologically relevant pyridopyrimidinone derivative, have been recently reported. However, most of these routes rely exclusively on palladium-catalyzed, cross-coupling reactions and involve low-yielding intermediates, which limit their scalability and complicate impurity control. In this work, we present a five-step, straightforward route to risdiplam, utilizing ethyl 2,8-dimethylimidazo[1,2-b]pyridazine-3-carboxylate—an accessible and cost-effective building block previously developed by our research group—as a starting material. The key step involves construction of the 4H-pyrido[1,2-a]pyrimidin-4-one scaffold via a copper(I)-catalyzed heterocyclization reaction. This represents a novel and convenient protocol for the synthesis of 2-(2,8-dimethylimidazo[1,2-b]pyridazin-6-yl)-7-fluoro-4H-pyrido[1,2-a]pyrimidin-4-one, which serves as a crucial intermediate in the final stages of risdiplam synthesis. The overall process allows us to obtain the target compound with a 20% total yield (from abovementioned starting material) and high purity (99.86%, by HPLC-UV), with a maximum level of unidentified impurities not exceeding 0.046%. The developed approach eliminates the use of palladium catalysis and chromatographic purification, offering a practical and scalable alternative for risdiplam production.

The increasing prevalence of antimicrobial resistance has stimulated interest in non-antibiotic small molecules that can restore or potentiate the activity of established antibacterial agents. In this study, a focused series of low-molecular-weight chromene derivatives was synthesized, structurally characterized, and evaluated primarily as antibacterial adjuvants rather than as stand-alone antibiotics. The experimental strategy was designed to distinguish intrinsic antibacterial activity from potentiating activity in combination with a partner antibiotic. Initial susceptibility testing was followed by combination experiments in selected bacterial strains, with particular emphasis on changes in the minimum inhibitory concentration (MIC) of meropenem or doripenem in the presence of each test compound. Broth microdilution combination assays demonstrated that compound 3a significantly reduced the MIC of meropenem and doripenem against methicillin-resistant Staphylococcus aureus (MRSA). The observed adjuvant effect suggests that chromene scaffolds may serve as promising candidates for the development of next-generation β-lactam enhancers aimed at overcoming carbapenem resistance.