From a series of small fragments that was designed to probe the histamine H(4) receptor (H(4)R), we previously described quinoxaline-containing fragments that were grown into high affinity H(4)R ligands in a process that was guided by pharmacophore modeling. With a scaffold hopping exercise and using the same in silico models, we now report the identification and optimization of a series of quinazoline-containing H(4)R compounds. This approach led to the discovery of 6-chloro-N-(furan-3-ylmethyl)2-(4-methylpiperazin-1-yl)quinazolin-4-amine (VUF10499, 54) and 6-chloro-2-(4-methylpiperazin-1-yl)-N-(thiophen-2-ylmethyl)quinazolin-4-amine (VUF10497, 55) as potent human H(4)R inverse agonists (pK(i) = 8.12 and 7.57, respectively). Interestingly, both compounds also possess considerable affinity for the human histamine H(1) receptor (H(1)R) and therefore represent a novel class of dual action H(1)R/H(4)R ligands, a profile that potentially leads to added therapeutic benefit. Compounds from this novel series of quinazolines are antagonists at the rat H(4)R and were found to possess anti-inflammatory properties in vivo in the rat.
Activating mutations in KRAS are the most frequent oncogenic alterations in cancer. The oncogenic hotspot position 12, located at the lip of the switch II pocket, offers a covalent attachment point for KRAS G12C inhibitors. To date, KRAS G12C inhibitors have been discovered by first covalently binding to the cysteine at position 12 and then optimizing pocket binding. We report on the discovery of the in vivo active KRAS G12C inhibitor BI-0474 using a different approach, in which small molecules that bind reversibly to the switch II pocket were identified and then optimized for non-covalent binding using structure-based design. Finally, the Michael acceptor containing warhead was attached. Our approach offers not only an alternative approach to discovering KRAS G12C inhibitors but also provides a starting point for the discovery of inhibitors against other oncogenic KRAS mutants.
Mouse double minute 2 (MDM2) is a main and direct inhibitor of the crucial tumor suppressor p53. Reports from initial clinical trials showed that blocking this interaction with a small‐molecule inhibitor can have great value in the treatment of cancer for patients with p53 wild‐type tumors; however, it also revealed dose‐limiting hematological toxicities and drug‐induced resistance as main issues. To overcome the former, an inhibitor with superior potency and pharmacokinetic properties to ultimately achieve full efficacy with less‐frequent dosing schedules is required. Toward this aim, we optimized our recently reported spiro‐oxindole inhibitors by focusing on the crucial interaction with the amino acid side chain of His96
MDM2
. The designed molecules required the targeted synthesis of structurally complex spiro[indole‐3,2′‐pyrrolo[2,3‐
c
]pyrrole]‐2,4′‐diones for which we developed an unprecedented intramolecular azomethine ylide cycloaddition and investigated the results by computational methods. One of the new compounds showed superior cellular potency over previously reported BI‐0252. This finding is a significant step toward an inhibitor suitable to potentially mitigate hematological on‐target adverse effects.
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