N-Demethylation of selected N-methylalkaloids using a modified Polonovski reaction can be accomplished employing nanoscale zero-valent iron, nZVI, in isopropanol.

A mechanochemical approach has been demonstrated for the selective cleavage of nitrogen–carbon bonds in the N-demethylation of various alkaloids relevant in the pharmaceutical industry. This methodology employs a range of so-called “liquid additives” used in microliter quantities in liquid assisted grinding rather than “solvents” used in solution phase reactions. Green liquid additives such as alcohols, water, PEG and ionic liquids as well as a nonchemical, mechanical approach for the generation of nanoscale Fe0 dust significantly improve the green attributes of the N-demethylation process.

The adenosine A 1 receptor is a therapeutic target based on its ability to provide cardioprotection during episodes of myocardial ischemia and reperfusion injury. However, the clinical translation of A 1 R agonists has been hindered by dose-limiting adverse effects (bradycardia and hypotension). Previously, we demonstrated that the bitopic agonist VCP746 (1), consisting of an adenosine pharmacophore linked to an allosteric moiety, can stimulate cardioprotective A 1 R signaling effects in the absence of unwanted bradycardia. This study maps the structure−activity relationships of 1 through modifications to the linker moiety. Derivatives differing in the flexibility, length, and nature of the linker were assessed, which revealed that the linker is tolerant of several modifications including added rigidity. Ligands featuring 1,4-disubstituted 1,2,3-triazoles were the most biased of the novel analogues but also displayed sub-nanomolar potency in a cAMP accumulation assay at the A 2B R. To our knowledge, 10 is the most potent A 2B R agonist published to date.

The development of new antimalarials is required because of the threat of resistance to current antimalarial therapies.To discover new antimalarial chemotypes, we screened the Janssen Jumpstarter library against the P. falciparum asexual parasite and identified the 7-N-substituted-3-oxadiazole quinolone hit class. We established the structure−activity relationship and optimized the antimalarial potency. The optimized analog WJM228 (17) showed robust metabolic stability in vitro, although the aqueous solubility was limited. Forward genetic resistance studies uncovered that WJM228 targets the Q o site of cytochrome b (cyt b), an important component of the mitochondrial electron transport chain (ETC) that is essential for pyrimidine biosynthesis and an established antimalarial target. Profiling against drug-resistant parasites confirmed that WJM228 confers resistance to the Q o site but not Q i site mutations, and in a biosensor assay, it was shown to impact the ETC via inhibition of cyt b. Consistent with other cyt b targeted antimalarials, WJM228 prevented pre-erythrocytic parasite and male gamete development and reduced asexual parasitemia in a P. berghei mouse model of malaria. Correcting the limited aqueous solubility and the high susceptibility to cyt b Q o site resistant parasites found in the clinic will be major obstacles in the future development of the 3-oxadiazole quinolone antimalarial class.

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