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General strategies for the chemical synthesis of organic compounds, especially of architecturally complex natural products, are not easily identified. Here we present a method to establish a strategy for such syntheses, which uses network analysis. This approach has led to the identification of a versatile synthetic intermediate that facilitated syntheses of the diterpenoid alkaloids weisaconitine D and liljestrandinine, and the core of gomandonine. We also developed a web-based graphing program that allows network analysis to be easily performed on molecules with complex frameworks. The diterpenoid alkaloids comprise some of the most architecturally complex and functional-group-dense secondary metabolites isolated. Consequently, they present a substantial challenge for chemical synthesis. The synthesis approach described here is a notable departure from other single-target-focused strategies adopted for the syntheses of related structures. Specifically, it affords not only the targeted natural products, but also intermediates and derivatives in the three families of diterpenoid alkaloids (C-18, C-19 and C-20), and so provides a unified synthetic strategy for these natural products. This work validates the utility of network analysis as a starting point for identifying strategies for the syntheses of architecturally complex secondary metabolites.

Neuropsychiatric disorders such as major depressive disorders and schizophrenia are often associated with disruptions to the normal 24 h sleep wake cycle. Casein kinase 1 (CK1δ) is an integral part of the molecular machinery that regulates circadian rhythms. Starting from a cluster of bicyclic pyrazoles identified from a virtual screening effort, we utilized structure-based drug design to identify and reinforce a unique "hinge-flip" binding mode that provides a high degree of selectivity for CK1δ versus the kinome. Pharmacokinetics, brain exposure, and target engagement as measured by ex vivo autoradiography are described for advanced analogs., Competing Interests: The authors declare no competing financial interest., (© 2024 American Chemical Society.)

A method for the preparation of highly functionalized 4-iodo-7-azaindazoles is reported. These valuable heterocycles are synthesized via condensation of 2-hydrazineylpyrimidines with various iodoalkynones followed by Diels-Alder/retro-Diels-Alder cyclization. The method is general to the formation of products with a variety of C 3 , C 5 , and C 6 substituents while preserving the C 4 iodide functional handle for further late-stage functionalization. The utility of this transformation is demonstrated through the rapid synthesis of several bioactive azaindazole targets.

We report the modular preparation of dihydro-1,2,5-thiodiazole dioxide heterocycles starting from methyl ketones and primary amines. This one-pot, three-component coupling employs 2,3-dimethylimidazole-1-sulfonyl azide triflate as a coupling reagent and oxidant. The transformation is scalable and various ketones and amines can be used, yielding thiodiazole dioxide products in up to 89% yield. In addition, 15 N- and 13 C-labeling studies suggest a mechanism involving a 1,2-nitrogen migration. Together with the mechanistic studies, DFT calculations provide insight into the reaction pathway and set the stage for further exploration of the mechanistic nuances of reactions that use sulfamoyl azides. In combination with the demonstrated modularity of the approach reported herein, the derivatization of the thiodiazole dioxide products highlights the potential of this methodology to rapidly access diverse chemical structures., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Azabicyclo[2.1.1]hexanes (aza-BCHs) and bicyclo[1.1.1]pentanes (BCPs) have emerged as attractive classes of sp 3 -rich cores for replacing flat, aromatic groups with metabolically resistant, three-dimensional frameworks in drug scaffolds. Strategies to directly convert, or "scaffold hop", between these bioisosteric subclasses through single-atom skeletal editing would enable efficient interpolation within this valuable chemical space. Herein, we describe a strategy to "scaffold hop" between aza-BCH and BCP cores through a nitrogen-deleting skeletal edit. Photochemical [2+2] cycloadditions, used to prepare multifunctionalized aza-BCH frameworks, are coupled with a subsequent deamination step to afford bridge-functionalized BCPs, for which few synthetic solutions currently exist. The modular sequence provides access to various privileged bridged bicycles of pharmaceutical relevance.

Orexin neurons originating in the perifornical and lateral hypothalamic area project to anxiety- and panic-associated neural circuitry, and are highly reactive to anxiogenic stimuli. Preclinical evidence suggests that the orexin system, and particularly the orexin-1 receptor (OX1R), may be involved in the pathophysiology of panic and anxiety. Selective OX1R antagonists thus may constitute a potential new treatment strategy for panic- and anxiety-related disorders. Here, we characterized a novel selective OX1R antagonist, JNJ-61393215, and determined its affinity and potency for human and rat OX1R in vitro. We also evaluated the safety, pharmacokinetic, and pharmacodynamic properties of JNJ-61393215 in first-in-human single- and multiple-ascending dose studies conducted. Finally, the potential anxiolytic effects of JNJ-61393215 were evaluated both in rats and in healthy men using 35% CO 2 inhalation challenge to induce panic symptoms. In the rat CO 2 model of panic anxiety, JNJ-61393215 demonstrated dose-dependent attenuation of CO 2 -induced panic-like behavior without altering baseline locomotor or autonomic activity, and had minimal effect on spontaneous sleep. In phase-1 human studies, JNJ-61393215 at 90 mg demonstrated significant reduction (P < 0.02) in CO 2 -induced fear and anxiety symptoms that were comparable to those obtained using alprazolam. The most frequently reported adverse events were somnolence and headache, and all events were mild in severity. These results support the safety, tolerability, and anxiolytic effects of JNJ-61393215, and validate CO 2 exposure as a translational cross-species experimental model to evaluate the therapeutic potential of novel anxiolytic drugs.

The hetisine-type natural products exhibit one of the most complex carbon skeletons within the diterpenoid alkaloid family. The use of network analysis has enabled a synthesis strategy to access alkaloids in this class with hydroxylation on the A-ring. Key transformations include a benzyne acyl-alkylation to construct a key fused 6-7-6 tricycle, a chemoselective nitrile reduction, and sequential C-N bond formations using a reductive cyclization and a photochemical hydroamination to construct an embedded azabicycle. Our strategy should enable access to myriad natural and unnatural products within the hetisine-type.

The secondary metabolites that comprise the diterpenoid alkaloids are categorized into C 18 , C 19 , and C 20 families depending on the number of contiguous carbon atoms that constitute their central framework. Herein, we detail our efforts to prepare these molecules by chemical synthesis, including a photochemical approach, and ultimately a bioinspired strategy that has resulted in the development of a unifying synthesis of one C 18 (weisaconitine D), one C 19 (liljestrandinine), and three C 20 (cochlearenine, paniculamine, and N-ethyl-1α-hydroxy-17-veratroyldictyzine) natural products from a common intermediate.

The denudatine-type diterpenoid alkaloids cochlearenine, N-ethyl-1α-hydroxy-17-veratroyldictyzine, and paniculamine have been synthesized for the first time (25, 26, and 26 steps from 16, respectively). These syntheses take advantage of a common intermediate (8) that we have previously employed in preparing aconitine-type natural products. The syntheses reported herein complete the realization of a unified strategy for the preparation of C20, C19, and C18 diterpenoid alkaloids., Competing Interests: Notes The authors declare no competing financial interest.

Orexins (OXs) are peptides produced by perifornical (PeF) and lateral hypothalamic neurons that exert a prominent role in arousal-related processes, including stress. A critical role for the orexin-1 receptor (OX1R) in complex emotional behavior is emerging, such as overactivation of the OX1R pathway being associated with panic or anxiety states. Here we characterize a brain-penetrant, selective, and high-affinity OX1R antagonist, compound 56 [N-({3-[(3-ethoxy-6-methylpyridin-2-yl)carbonyl]-3-azabicyclo[4.1.0]hept-4-yl}methyl)-5-(trifluoromethyl)pyrimidin-2-amine]. Ex vivo receptor binding studies demonstrated that, after subcutaneous administration, compound 56 crossed the blood-brain barrier and occupied OX1Rs in the rat brain at lower doses than standard OX1R antagonists GSK-1059865 [5-bromo-N-({1-[(3-fluoro-2-methoxyphenyl)carbonyl]-5-methylpiperidin-2-yl}methyl)pyridin-2-amine], SB-334867 [1-(2-methyl-1,3-benzoxazol-6-yl)-3-(1,5-naphthyridin-4-yl)urea], and SB-408124 [1-(6,8-difluoro-2-methylquinolin-4-yl)-3-[4-(dimethylamino)phenyl]urea]. Although compound 56 did not alter spontaneous sleep in rats and in wild-type mice, its administration in orexin-2 receptor knockout mice selectively promoted rapid eye movement sleep, demonstrating target engagement and specific OX1R blockade. In a rat model of psychological stress induced by cage exchange, the OX1R antagonist prevented the prolongation of sleep onset without affecting sleep duration. In a rat model of panic vulnerability (involving disinhibition of the PeF OX region) to threatening internal state changes (i.e., intravenous sodium lactate infusion), compound 56 attenuated sodium lactate-induced panic-like behaviors and cardiovascular responses without altering baseline locomotor or autonomic activity. In conclusion, OX1R antagonism represents a novel therapeutic strategy for the treatment of various psychiatric disorders associated with stress or hyperarousal states., (Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.)

The orexin, or hypocretin, neuropeptides (orexin-A and orexin-B) are produced on neurons in the hypothalamus which project to key areas of the brain that control sleep-wake states, modulation of food intake, panic, anxiety, emotion, reward and addictive behaviors. These neuropeptides exert their effects on a pair of G-protein coupled receptors termed the orexin-1 (OX1) and orexin-2 (OX2) receptors. Emerging biology suggests the involvement of these receptors in psychiatric disorders as they are thought to play a key role in the regulation of multiple systems. This review is intended to highlight key selective OX1 or OX2 small-molecule antagonists., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The yohimbinoid alkaloids continue to receive considerable attention from the synthetic community because of their interesting chemical structures and varied biological activity. Although there are several elegant syntheses of certain members of this group of alkaloids, a truly unified approach has yet to be developed. In short, general approaches to this compound class are hampered by a lack of complete control in setting the C(3) stereocentre at a late stage. Herein, we report that a functionalized hydrindanone enables a divergent strategy that builds on existing precedent to address this long-standing challenge. Utilizing an aminonitrile intermediate, the stereochemistry at C(3) of the yohimbinoid skeleton can be controlled effectively in a Pictet-Spengler reaction. We applied this approach to the first total syntheses of the C(3) epimeric natural products venenatine and alstovenine.

An efficient synthesis of the octahydro-1H-2,4-methanoindene core of phragmalin-type limonoids, such as xyloccensins O and P, is reported. The success of the synthetic route is predicated on the use of network analysis in the retrosynthetic analysis and a Diels-Alder reaction for the synthesis of a key hydrindanone derivative., (© 2012 American Chemical Society)

A Zn(NTf(2))(2) catalyzed tandem reaction consisting of a nucelophilic ring opening of 1,1-cyclopropanediesters by 2-alkynyl indoles followed by a Conia-ene ring closure results in the efficient one-step synthesis of tetrahydrocarbazoles. The adducts may be further elaborated to carbazoles.

Lewis acid catalyzed ring opening of 1,1-cyclopropanediesters by the hydroxyl group of a propargyl alcohol sets up a subsequent Conia-ene cyclization to afford substituted tetrahydropyrans in a one-pot, high-yielding procedure.

The reaction of hydrazinoethyl 1,1-cyclopropanediesters with aldehydes in the presence of catalytic Yb(OTf)(3) allows access to structurally complex fused bicyclo pyrazolidines. Either 2,5-cis or 2,5-trans adducts can be obtained in good to excellent yields in most cases by simply controlling the order of addition of the catalyst and aldehyde.

The reaction of benzyl-protected propargyl amines and 1,1-cyclopropane diesters in the presence of catalytic Zn(NTf(2))(2) allows access to highly functionalized piperidines in excellent yields. The process proceeds via a tandem cyclopropane ring-opening/Conia-ene cyclization.

The first total syntheses of clausamines A-C and clausevatine D are reported. The key step involves a Diels-Alder reaction between an imine quinone and cyclic diene, allowing for the subsequent construction of the carbazole core in a regiospecific manner. Stereochemistry of the natural products is also discussed.

The Diels-Alder reaction between a quinone monoimine and cyclic diene allows for the construction of substituted carbazoles in a regiospecific manner. This methodology has sucessfully been employed in a divergent strategy, culminating in the synthesis of eustifolines A-D and glycomaurrol.

The excited-state quenching of zinc meso-tetrakis(4-sulfonatophenyl)porphyrin (ZnTPPS) by halide ions has been studied in water and various aqueous micellar solutions using both steady-state and time-resolved fluorescence techniques. The quenching efficiencies of the S(1) state of ZnTPPS ([small tau][approximate] 1.93 ns) by halide ions in homogeneous aqueous solution increase in the order Cl(-) < Br(-) < I(-); both dynamic and static quenching processes are involved. The mechanisms which may possibly be operating (i.e. electron transfer, heavy atom effect and Watkins mechanism) are discussed. Quenching of the short-lived S(2) state ([small tau][approximate] 1.3 ps) of ZnTPPS is only possible using I(-); it is suggested that the quenching mechanism proceeds via electron transfer between the fluorophore and I(-) within the quenching sphere of action. The results are consistent with the Gibbs free energy change ([capital Delta]G[degree]) involved in the charge-separation process. Finally, the fluorescence quenching of ZnTPPS by bromide ions in both cationic (DTAB and CTAC) and neutral (TX-100) micelles has been examined. The quenching observed in the cationic micelles is rationalised using a water-filled channel model, whereby Br(-) ions diffuse down these channels to achieve close proximity to the fluorophore. No emission quenching was observed in the case of the neutral TX-100 micelles.

Trimethylsilylselenoferrocene 1 has been prepared in good yield. The reactive silyl group on 1 is used as a driving force for the synthesis [Cl4Cd4[mu2-Se(C5H4)Fe(C5H5))6]2- 2, a Cd4Se6 adamantoid cluster with six surface ferrocenyl groups.