Herein, we report the synthesis and characterization of a novel set of substituted indazole-ethanamines and indazole-tetrahydropyridines as potent serotonin receptor subtype 2 (5-HT2) agonists. Specifically, we examine the 5-HT2 pharmacology of the direct indazole analogs of 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and related serotonergic tryptamines, and highlight the need for rigorous characterization of 5-HT2 subtype selectivity for these analogs, particularly for the 5-HT2B receptor subtype. Within this series, the potent analog VU6067416 (19d) was optimized to have suitable preclinical pharmacokinetic properties for in vivo dosing, although potent 5-HT2B agonist activity precluded further characterization for this series. Additionally, in silico docking studies suggest that the high potency of 19d may be a consequence of a halogen-bonding interaction with Phe2345.38 in the 5-HT2A orthosteric pocket.

In neuroblastoma, MCYN amplification is associated with survival rates of <50%. Overexpression of the mitotic kinases Aurora-A and Aurora-B are also associated with low survival and exacerbate the oncogenic effects of N-Myc. As N-Myc is stabilized by Aurora-A, Aurora-A targeting proteolysis targeting chimeras (PROTACs) have been developed that reduce Aurora-A and N-Myc levels. However, simultaneous degradation of N-Myc, Aurora-A, and Aurora-B has not been previously achieved. Given the contributions of both Aurora kinases to MYCN-amplified neuroblastoma, we designed PROTACs capable of degrading both Aurora-A and Aurora-B. Dual-degrading PROTACs dAurAB2 and dAurAB5 potently degraded Aurora-A (DC50 = 59 nM and 8.8 nM, respectively) and Aurora-B (DC50 = 39 nM and 6.1 nM), eliminated 89% - 97% of Aurora-A and Aurora-B, and reduced N-Myc levels by 38% and 45% in MCYN-amplified IMR32 neuroblastoma cells. Global proteomics screening revealed that while dAurAB2 demonstrated good selectivity, dAurAB5 downregulated additional targets including threonine tyrosine kinase (TTK). Interestingly, TKK is also associated with MCYN-amplified neuroblastoma, and multi-target PROTAC dAurAB5 reduced the viability of neuroblastoma IMR32 cells by 55% at 24 hours. The development of dAurAB2 and dAurAB5 generates new modalities for inhibiting the oncogenic activities of Aurora-A, Aurora-B, N-Myc, and TTK in neuroblastoma and other cancers.

Kir6.2/SUR1 is an ATP-regulated potassium channel that acts as an intracellular metabolic sensor, controlling insulin and appetite-stimulatory neuropeptides secretion. In this Letter, we present the SAR around a novel Kir6.2/SUR1 channel opener scaffold derived from an HTS screening campaign. New series of compounds with tractable SAR trends and favorable potencies are reported.

Previously described approaches for the alkylation of NH-sulfoximines typically rely either on transition metal catalysis, or the use of traditional alkylation reagents and strong bases. Herein, we report a straightforward alkylation of diverse NH-sulfoximines under simple Mitsunobu-type conditions, despite the unusually high pKa of the NH center.

Target validation is key to the development of protein degrading molecules such as proteolysis-targeting chimeras (PROTACs) to identify cellular proteins amenable for induced degradation by the ubiquitin-proteasome system (UPS). Previously the HaloPROTAC system was developed to screen targets of PROTACs by linking the chlorohexyl group with the ligands of E3 ubiquitin ligases VHL and cIAP1 to recruit target proteins fused to the HaloTag for E3-catalyzed ubiquitination. Reported here are HaloPROTACs that engage the cereblon (CRBN) E3 to ubiquitinate and degrade HaloTagged proteins. A focused library of CRBN-pairing HaloPROTACs was synthesized and screened to identify efficient degraders of EGFP-HaloTag fusion with higher activities than VHL-engaging HaloPROTACs at sub-micromolar concentrations of the compound. The CRBN-engaging HaloPROTACs broadens the scope of the E3 ubiquitin ligases that can be utilized to screen suitable targets for induced protein degradation in the cell.

The stereoselective synthesis of terminal bromo-substituted propargylamines via in situ generation of lithium bromoacetylide from 1,2-dibromoethene and addition to Ellman chiral N-tert-butanesulfinyl aldimines is reported. Modest to good yields (43-85%) and diastereoselectivity (dr = 3:1 to >20:1) were achieved for a range of aryl, heteroaryl, alkyl, and α,β-unsaturated substrates. Terminal bromo-substituted propargylamines prepared via this method can be directly used in the frequently employed Cadiot-Chodkiewicz coupling to produce functionalized diynes. The method reported here increases the structural diversity of chiral terminal bromo-substituted propargylamines that can be readily synthesized as previous methods for the stereoselective synthesis of these compounds rely on amino acid precursors from the chiral pool.