In response to the pressing global challenge of antibiotic resistance, time efficient design and synthesis of novel antibiotics are of immense need. Polycyclic polyprenylated acylphloroglucinols (PPAP) were previously reported to effectively combat a range of gram-positive bacteria. Although the exact mode of action is still not clear, we conceptualized a late-stage divergent synthesis approach to expand our natural product-based PPAP library by 30 additional entities to perform SAR studies against methicillin-resistant Staphylococcus aureus (MRSA). Although at this point only data from cellular assays are available and understanding of molecular drug-target interactions are lacking, the experimental data were used to generate 3D-QSAR models via an artificial intelligence training and to identify a common pharmacophore model. The experimentally validated QSAR model enabled the estimation of anti-MRSA activities of a virtual compound library consisting of more than 100,000 in-silico generated B PPAPs, out of which the 20 most promising candidates were synthesized. These novel PPAPs revealed significantly improved cellular activities against MRSA with growth inhibition down to concentrations less than 1 μm.

Selective modulation of TRPC6 ion channels is a promising therapeutic approach for neurodegenerative diseases and depression. A significant advancement showcases the selective activation of TRPC6 through metalated type-B PPAP, termed PPAP53. This success stems from PPAP53's 1,3-diketone motif facilitating metal coordination. PPAP53 is water-soluble and as potent as hyperforin, the gold standard in this field. In contrast to type-A, type-B PPAPs offer advantages such as gram-scale synthesis, easy derivatization, and long-term stability. Our investigations reveal PPAP53 selectively binding to the C-terminus of TRPC6. Although cryoelectron microscopy has resolved the majority of the TRPC6 structure, the binding site in the C-terminus remained unresolved. To address this issue, we employed state-of-the-art artificial-intelligence-based protein structure prediction algorithms to predict the missing region. Our computational results, validated against experimental data, indicate that PPAP53 binds to the 777LLKL780-region of the C-terminus, thus providing critical insights into the binding mechanism of PPAP53.

The selective modulation of TRPC6 ion channels has emerged as a promising therapeutic approach for treating neuro-degenerative diseases and depression. Here, we present a significant advancement in this field by demonstrating the se-lective activation of TRPC6 using a metallated type-B PPAP, designated as PPAP53. The success of PPAP53 is attributed to the utilization of the 1,3-diketone motif present in PPAPs for metal coordination. The metallated PPAPs exhibit water solubility and equipotent activity compared to hyperforin, which is a natural product and considered the gold standard in the field. Notably, and in sharp contrast to type-A PPAPs, type-B PPAPs possess unique properties such as synthetic ac-cessibility in gram scale, facile derivatization, being thermally stable and stable against photochemical oxidation. Our detailed investigations reveal that PPAP53 selectively binds to the C-terminus of TRPC6. Although cryo electron micros-copy has resolved the majority of the TRPC6 structure, the binding site in the C-terminus remained unresolved. To ad-dress this issue, we employed state-of-the-art artificial intelligence-based protein structure prediction algorithms, includ-ing AlphaFold2, ColabFold, and trRosetta, to predict the missing C-terminus region. Our computational results, validated against experimental data, indicate that PPAP53 binds to the 777LLKL780-region of the C-terminus, thus providing critical insights into the binding mechanism of PPAP53 with TRPC6.

Before the emergence of SARS-CoV-2, tuberculosis (TB) was the leading cause of infectious disease mortality worldwide. Like all antibiotic-exposed bacteria Mycobacterium tuberculosis (Mtb) developed multidrug-resistant (MDR) and exten-sively drug-resistant (XDR) strains which require new antibiotics with novel mechanism of actions. Hyperforin, a natural type-A polyprenylated polycyclic acylphloroglucinol (PPAP) isolated from St. John’s wort, is known for its antibacterial, antidepressant and antimycobacterial activity. However, hyperforin is not stable and easily degradable in light, heat it and oxidizes. Here we report photo- and benchstable type-B PPAPs with structural similarity to hyperforin and enhanced an-timycobacterial activity. We tested a panel of PPAPs and identified our previously reported molecule PPAP22 as lead compound. Converting PPAP22 into the corresponding sodium salt, PPAP53, enhanced the solubility dramatically. We show that PPAP53 inhibits the growth of virulent, extracellular Mtb. Strikingly, the activity is more pronounced intracel-lular Mtb residing in human primary macrophages without damaging the host cell or lung cells. Importantly PPAP53 was also highly active against drug-resistant Mtb. Additionally, we analysed the in vitro properties of PPAP53 in terms of CYP-induction and PXR interaction. Taken together we introduce type-B PPAPs are a new class of antimycobacterial com-pounds, with remarkable activity and favorouble physical properties.

Novel chemical space has been explored by the synthesis and in vitro evaluation of sulfonimidamides. This functional group has only recently received growing interest as a versatile pharmacophore, but the methodology for its synthesis and the understanding of its properties are still very limited. Application of various reaction conditions for the N-functionalization of sulfoximines to an NH sulfonimidamide model compound yielded a set of structurally diverse products. In vitro assessment of selected compounds did not reveal any intrinsic flaw for medicinal chemistry. More information can be found in the Full Paper by U. Lücking, R. Stockman, et al. on page 9295.

The key learnings of the utilization of sulfoximines, sulfondiimines and sulfonimidamides in drug discovery at Bayer AG are shared.

An unprecedented set of structurally diverse sulfonimidamides (47 compounds) has been prepared by various N-functionalization reactions of tertiary =NH sulfonimidamide 2 aa. These N-functionalization reactions of model compound 2 aa include arylation, alkylation, trifluoromethylation, cyanation, sulfonylation, alkoxycarbonylation (carbamate formation) and aminocarbonylation (urea formation). Small molecule X-ray analyses of selected N-functionalized products are reported. To gain further insight into the properties of sulfonimidamides relevant to medicinal chemistry, a variety of structurally diverse reaction products were tested in selected in vitro assays. The described N-functionalization reactions provide a short and efficient approach to structurally diverse sulfonimidamides which have been the subject of recent, growing interest in the life sciences.

Unprotected tertiary sulfonimidamides have been prepared in good to excellent yields in a one-pot transformation from tertiary sulfinamides through NH transfer. The reaction is mediated by commercially available (diacetoxyiodo)benzene and ammonium carbamate in methanol under convenient conditions. A wide range of functional groups are tolerated and initial results indicate that the NH transfer is stereospecific. A small molecule X-ray analysis of NH sulfonimidamide 2 a and its behavior in selected in vitro assays in comparison to the matched sulfonamide are also reported. This new reaction provides a safe, short and efficient approach to sulfonimidamides, which have been the subject of recent, growing interest in the life sciences.