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Martin SF. Bridging Known and Unknown Unknowns: From Natural Products and Their Mimics to Unmet Needs in Neuroscience. Acc Chem Res 2022; 55:2397-2408. [PMID: 35960884 DOI: 10.1021/acs.accounts.1c00773] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Scientific excursions into the unknown are often characterized by unanticipated twists and turns that may lead in directions that never could have been predicted. Decisions made during the course of these explorations determine what we discover. This Account chronicles one such journey that began with a challenge encountered during the synthesis of a natural product and then unfolded over more than 30 years to focus on unmet needs in neuroscience. Specifically, while developing a concise approach to tetrahydroalstonine, a heteroyohimboid alkaloid having α-adrenergic activity, we faced the predicament of assembling a key intermediate. Solving this problem resulted in the serendipitous discovery of the vinylogous Mannich reaction and a productive program wherein we used this powerful construction as a key step in the syntheses of numerous alkaloids. However, we also realized that lessons learned from the synthesis of tetrahydroalstonine could be generalized to invent a new strategy for preparing diverse collections of substituted nitrogen heterocycles that could be screened against biological targets. The approach featured the combination of several reactants in a multicomponent assembly process to give a functionalized intermediate that could be elaborated by various ring-forming reactions to give heterocyclic scaffolds that could be further diversified. Screening these compound sets against a broad range of biological targets revealed some intriguing hits, but none of them led to a productive collaboration in translational research. Notwithstanding this setback, we screened curated members of our collections against proteins in the central nervous system and discovered some substituted B-norbenzomorphans that were selective for the enigmatic sigma-2 receptor (σ2R), an understudied protein that had been primarily associated with cancer. With scant knowledge of its role in neuroscience, we posited that small molecules that bind to σ2R might be neuroprotective, thus launching a new venture. In parallel investigations we prepared analogues of the initial hits, explored their effects in animal models of neurodegenerative and neurological conditions, and identified σ2R as transmembrane protein 97 (TMEM97). After first establishing the neuroprotective effects of several σ2R/TMEM97 ligands in a transgenic Caenorhabditis elegans model of neurodegeneration, we showed that one of these has procognitive effects and reduces levels of proinflammatory cytokines in a transgenic mouse model of Alzheimer's disease. We then identified a closely related σ2R/TMEM97 ligand that mitigates hippocampal-dependent memory deficits, prevents axon degeneration, and protects neurons and oligodendrocytes after traumatic brain injury. In a recent study, this compound was shown to protect retinal ganglion cells from retinal ischemia/reperfusion injury. In other collaborative investigations, we have shown that related, but structurally distinct, σ2R/TMEM97 ligands alleviate neuropathic pain, while a σ2R/TMEM97 ligand representing yet another chemotype reduces impairments associated with alcohol withdrawal. More recently, we have shown that σ2R/TMEM97 ligands enhance survival of cortical neurons in a neuronal model of Huntington's disease. Translational and mechanistic studies in these and other areas are in progress. Solving a problem we faced in natural product synthesis thus served as an unexpected gateway to discoveries that could lead to entirely new approaches to treat neurodegenerative and neurological conditions by targeting σ2R/TMEM97, a protein that has never been associated with these afflictions.
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Affiliation(s)
- Stephen F Martin
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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2
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Wang L, Han H, Gu L, Zhang W, Zhao J, Wang Q. Skeletal remodeling of chalcone-based pyridinium salts to access isoindoline polycycles and their bridged derivatives. Chem Sci 2021; 12:15389-15398. [PMID: 34976360 PMCID: PMC8635221 DOI: 10.1039/d1sc05741c] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/05/2021] [Indexed: 12/12/2022] Open
Abstract
Simultaneous deconstructive ring-opening and skeletal reconstruction of an inert, aromatic pyridinium ring is of great importance in synthetic communities. However, research in this area is still in its infancy. Here, a skeletal re-modeling strategy was developed to transform chalcone-based pyridinium salts into structurally intriguing polycyclic isoindolines through a dearomative ring-opening/ring-closing sequence. Two distinct driving forces for the deconstruction of the pyridinium core were involved in these transformations. One was the unprecedented harnessing of the instability of in situ generated cyclic β-aminoketones, and the other was the instability of the resultant N,N-ketals. The desired isoindoline polycycles could undergo the Wittig reaction with various phosphorus ylides to achieve structural diversity and complexity. Notably, by tuning the Wittig conditions by addition of one equivalent of base, an additional bridged ring was introduced. A plausible mechanism was proposed on the basis of control experiments and theoretical calculations.
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Affiliation(s)
- Lele Wang
- College of Chemistry and Chemical Engineering, Henan University Kaifeng 475004 China
| | - Huabin Han
- College of Chemistry and Chemical Engineering, Henan University Kaifeng 475004 China
| | - Lijie Gu
- College of Chemistry and Chemical Engineering, Henan University Kaifeng 475004 China
| | - Wenjing Zhang
- Green Catalysis Center, College of Chemistry, Zhengzhou University Zhengzhou 450001 China
| | - Junwei Zhao
- College of Chemistry and Chemical Engineering, Henan University Kaifeng 475004 China
| | - Qilin Wang
- College of Chemistry and Chemical Engineering, Henan University Kaifeng 475004 China
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2,2′-(Arylmethylene)bis(3-hydroxy-5,5-dimethylcyclohex-2-enone) crystals formation via atom economy reaction and their antioxidant activity. MONATSHEFTE FUR CHEMIE 2021. [DOI: 10.1007/s00706-021-02767-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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4
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Abeykoon GA, Sahn JJ, Martin SF. Novel substituted triazolo benzodiazepine scaffolds to explore chemical space. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.152828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Peach ML, Beedie SL, Chau CH, Collins MK, Markolovic S, Luo W, Tweedie D, Steinebach C, Greig NH, Gütschow M, Vargesson N, Nicklaus MC, Figg WD. Antiangiogenic Activity and in Silico Cereblon Binding Analysis of Novel Thalidomide Analogs. Molecules 2020; 25:E5683. [PMID: 33276504 PMCID: PMC7730988 DOI: 10.3390/molecules25235683] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/25/2020] [Accepted: 11/27/2020] [Indexed: 12/14/2022] Open
Abstract
Due to its antiangiogenic and anti-immunomodulatory activity, thalidomide continues to be of clinical interest despite its teratogenic actions, and efforts to synthesize safer, clinically active thalidomide analogs are continually underway. In this study, a cohort of 27 chemically diverse thalidomide analogs was evaluated for antiangiogenic activity in an ex vivo rat aorta ring assay. The protein cereblon has been identified as the target for thalidomide, and in silico pharmacophore analysis and molecular docking with a crystal structure of human cereblon were used to investigate the cereblon binding abilities of the thalidomide analogs. The results suggest that not all antiangiogenic thalidomide analogs can bind cereblon, and multiple targets and mechanisms of action may be involved.
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Affiliation(s)
- Megan L. Peach
- Basic Science Program, Chemical Biology Laboratory, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, MD 21701, USA;
| | - Shaunna L. Beedie
- Molecular Pharmacology Section, Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA; (S.L.B.); (C.H.C.); (M.K.C.); (S.M.)
- School of Medicine, Medical Sciences & Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK;
| | - Cindy H. Chau
- Molecular Pharmacology Section, Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA; (S.L.B.); (C.H.C.); (M.K.C.); (S.M.)
| | - Matthew K. Collins
- Molecular Pharmacology Section, Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA; (S.L.B.); (C.H.C.); (M.K.C.); (S.M.)
| | - Suzana Markolovic
- Molecular Pharmacology Section, Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA; (S.L.B.); (C.H.C.); (M.K.C.); (S.M.)
| | - Weiming Luo
- Drug Design & Development Section, Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (W.L.); (D.T.); (N.H.G.)
| | - David Tweedie
- Drug Design & Development Section, Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (W.L.); (D.T.); (N.H.G.)
| | - Christian Steinebach
- Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany; (C.S.); (M.G.)
| | - Nigel H. Greig
- Drug Design & Development Section, Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD 21224, USA; (W.L.); (D.T.); (N.H.G.)
| | - Michael Gütschow
- Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany; (C.S.); (M.G.)
| | - Neil Vargesson
- School of Medicine, Medical Sciences & Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK;
| | - Marc C. Nicklaus
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD 21701, USA;
| | - William D. Figg
- Molecular Pharmacology Section, Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA; (S.L.B.); (C.H.C.); (M.K.C.); (S.M.)
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Abstract
Human African trypanosomiasis (HAT) is a deadly neglected tropical disease caused by the protozoan parasite Trypanosoma brucei. During the course of screening a collection of diverse nitrogenous heterocycles, we discovered two novel compounds that contain the tetracyclic core of the Yohimbine and Corynanthe alkaloids, were potent inhibitors of T. brucei proliferation and T. brucei methionyl-tRNA synthetase (TbMetRS) activity. Inspired by these key findings, we prepared several novel series of hydroxyalkyl δ-lactam, δ-lactam, and piperidine analogs and tested their anti-trypanosomal activity. A number of inhibitors are more potent against T. brucei than these initial hits with one hydroxyalkyl δ-lactam derivative being 25-fold more effective in our assay. Surprisingly, most of these active compounds failed to inhibit TbMetRS. This work underscores the importance of verifying, irrespective of close structural similarities, that new compounds designed from a lead with a known biological target engage the putative binding site.
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Phelan ZK, Weiss PS, He Y, Guan Z, Thamattoor DM, Griffith DR. Synthetic Entry to the 2-Azatricyclo[4.3.2.0 4,9]undecane Ring System via Tropone. J Org Chem 2020; 85:2202-2212. [PMID: 31904976 DOI: 10.1021/acs.joc.9b02921] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A synthesis of the 2-azatricyclo[4.3.2.04,9]undecane ring system-a hitherto unreported bridged azatricyclic ring system-beginning from tricarbonyl(tropone)iron and allylamine was accomplished in three steps: (1) aza-Michael addition of allylamine to tricarbonyl(tropone)iron; (2) Boc-protection of the resulting secondary amine; and (3) oxidative demetallation leading to a spontaneous intramolecular Diels-Alder reaction. The effect of a variety of parameters on the intramolecular Diels-Alder reaction was investigated, including diene and dienophile substitution patterns and dienophile tether length.
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Affiliation(s)
- Zaki K Phelan
- Department of Chemistry , Lafayette College , Easton , Pennsylvania 18042 , United States
| | - Philip S Weiss
- Department of Chemistry , Lafayette College , Easton , Pennsylvania 18042 , United States
| | - Yiqun He
- Department of Chemistry , Lafayette College , Easton , Pennsylvania 18042 , United States
| | - Ziyang Guan
- Department of Chemistry , Lafayette College , Easton , Pennsylvania 18042 , United States
| | - Dasan M Thamattoor
- Department of Chemistry , Colby College , Waterville , Maine 04901 , United States
| | - Daniel R Griffith
- Department of Chemistry , Lafayette College , Easton , Pennsylvania 18042 , United States
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Linkens K, Schmidt HR, Sahn JJ, Kruse AC, Martin SF. Investigating isoindoline, tetrahydroisoquinoline, and tetrahydrobenzazepine scaffolds for their sigma receptor binding properties. Eur J Med Chem 2018; 151:557-567. [DOI: 10.1016/j.ejmech.2018.02.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 12/13/2022]
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Abstract
Diverse structural types of natural products and their mimics have served as targets of opportunity in our laboratory to inspire the discovery and development of new methods and strategies to assemble polyfunctional and polycyclic molecular architectures. Furthermore, our efforts toward identifying novel compounds having useful biological properties led to the creation of new targets, many of which posed synthetic challenges that required the invention of new methodology. In this Perspective, selected examples of how we have exploited a diverse range of natural products and their mimics to create, explore, and solve a variety of problems in chemistry and biology will be discussed. The journey was not without its twists and turns, but the unexpected often led to new revelations and insights. Indeed, in our recent excursion into applications of synthetic organic chemistry to neuroscience, avoiding the more-traveled paths was richly rewarding.
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Affiliation(s)
- Stephen F Martin
- Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States
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10
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Sahn JJ, Hodges TR, Chan JZ, Martin SF. Norbenzomorphan Scaffold: Chemical Tool for Modulating Sigma Receptor-Subtype Selectivity. ACS Med Chem Lett 2017; 8:455-460. [PMID: 28435536 DOI: 10.1021/acsmedchemlett.7b00066] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 03/21/2017] [Indexed: 01/11/2023] Open
Abstract
Some norbenzomorphans exhibit high affinity for sigma 1 and sigma 2 receptors, and varying the position of substituents on the aromatic ring of this scaffold has a significant effect on subtype selectivity. In particular, compounds bearing several different substituents at C7 of the norbenzomorphan ring system exhibit a general preference for the sigma 1 receptor, whereas the corresponding C8-substituted analogues preferentially bind at the sigma 2 receptor. These findings suggest that the norbenzomorphan scaffold may be a unique chemical template that can be easily tuned to prepare small molecules for use as tool compounds to study the specific biological effects arising from preferential binding at either sigma receptor subtype. In the absence of structural characterization data for the sigma 2 receptor, such compounds will be useful toward refining the pharmacophore model of its binding site.
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Affiliation(s)
- James J. Sahn
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Timothy R. Hodges
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Jessica Z. Chan
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Stephen F. Martin
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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11
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Wang H, Zhou W, Tao M, Hu A, Zhang J. Functionalized Tetrahydropyridines by Enantioselective Phosphine-Catalyzed Aza-[4 + 2] Cycloaddition of N-Sulfonyl-1-aza-1,3-dienes with Vinyl Ketones. Org Lett 2017; 19:1710-1713. [DOI: 10.1021/acs.orglett.7b00489] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Huamin Wang
- Shanghai Key Laboratory of
Green Chemistry and Chemical Processes, School of Chemistry and Molecular
Engineering, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, P. R. China
| | - Wei Zhou
- Shanghai Key Laboratory of
Green Chemistry and Chemical Processes, School of Chemistry and Molecular
Engineering, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, P. R. China
| | - Mengna Tao
- Shanghai Key Laboratory of
Green Chemistry and Chemical Processes, School of Chemistry and Molecular
Engineering, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, P. R. China
| | - Anjing Hu
- Shanghai Key Laboratory of
Green Chemistry and Chemical Processes, School of Chemistry and Molecular
Engineering, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, P. R. China
| | - Junliang Zhang
- Shanghai Key Laboratory of
Green Chemistry and Chemical Processes, School of Chemistry and Molecular
Engineering, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, P. R. China
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12
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Sahn JJ, Hodges TR, Chan JZ, Martin SF. Norbenzomorphan Framework as a Novel Scaffold for Generating Sigma 2 Receptor/PGRMC1 Subtype-Selective Ligands. ChemMedChem 2016; 11:556-61. [PMID: 26915462 PMCID: PMC4811364 DOI: 10.1002/cmdc.201500551] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/12/2016] [Indexed: 12/20/2022]
Abstract
A novel structural class with high affinity and subtype selectivity for the sigma 2 receptor has been discovered. Preliminary structure-affinity relationship data are presented showing that 8-substituted 1,3,4,5-tetrahydro-1,5-methanobenzazepine (norbenzomorphan) derivatives elicit modest to high selectivity for the sigma 2 over the sigma 1 receptor subtype. Indeed, piperazine analogue 8-(4-(3-ethoxy-3-oxopropyl)piperazin-1-yl)-1,3,4,5-tetrahydro-1,5-methanobenzazepine-2-carboxylate (SAS-1121) is 574-fold selective for the sigma 2 over the sigma 1 receptor, thereby establishing it as one of the more subtype-selective sigma 2 binding ligands reported to date. Emerging evidence has implicated the sigma 2 receptor in multiple health disorders, so the drug-like characteristics of many of the selective sigma 2 receptor ligands disclosed herein, coupled with their structural similarity to frameworks found in known drugs, suggest that norbenzomorphan analogues may be promising candidates for further development into drug leads.
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Affiliation(s)
- James J Sahn
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Stop A5300, Austin, TX, 78712, USA
| | - Timothy R Hodges
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Stop A5300, Austin, TX, 78712, USA
| | - Jessica Z Chan
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Stop A5300, Austin, TX, 78712, USA
| | - Stephen F Martin
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Stop A5300, Austin, TX, 78712, USA.
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Khan MM, Khan S, Saigal S, Iqbal S. Recent developments in multicomponent synthesis of structurally diversified tetrahydropyridines. RSC Adv 2016. [DOI: 10.1039/c6ra06767k] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Tetrahydropyridines (THPDs) have recognized as a major constituent of naturally occurring alkaloids and exhibits various biological and pharmacological profiles. For their synthesis, MCRs are employed as an excellent tool to generate vast libraries.
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Affiliation(s)
| | - Sarfaraz Khan
- Department of Chemistry
- Aligarh Muslim University
- Aligarh-202002
- India
| | - Saigal Saigal
- Department of Chemistry
- Aligarh Muslim University
- Aligarh-202002
- India
| | - Safia Iqbal
- Department of Chemistry
- Aligarh Muslim University
- Aligarh-202002
- India
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14
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Cheng B, Sunderhaus JD, Martin SF. Applications of Ring Closing Metathesis. Total Synthesis of (±)-Pseudotabersonine. Tetrahedron 2015; 71:7323-7331. [PMID: 26300565 DOI: 10.1016/j.tet.2015.04.082] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
A novel approach to the Aspidosperma family of alkaloids was developed and applied to a concise total synthesis of (±)-pseudotabersonine that was accomplished in 11 steps. Key transformations include a stepwise variant of a Mannich-like multicomponent assembly process, a double ring-closing metathesis sequence, and a one-pot deprotection/cyclization reaction.
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Affiliation(s)
- Bo Cheng
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
| | - James D Sunderhaus
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
| | - Stephen F Martin
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
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Zhang Y, Wu S, Wang S, Fang K, Dong G, Liu N, Miao Z, Yao J, Li J, Zhang W, Sheng C, Wang W. Divergent Cascade Construction of Skeletally Diverse “Privileged” Pyrazole-Derived Molecular Architectures. European J Org Chem 2015. [DOI: 10.1002/ejoc.201403673] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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16
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Sahn JJ, Granger BA, Martin SF. Evolution of a strategy for preparing bioactive small molecules by sequential multicomponent assembly processes, cyclizations, and diversification. Org Biomol Chem 2014; 12:7659-72. [PMID: 25135846 PMCID: PMC4167917 DOI: 10.1039/c4ob00835a] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A strategy for generating diverse collections of small molecules has been developed that features a multicomponent assembly process (MCAP) to efficiently construct a variety of intermediates possessing an aryl aminomethyl subunit. These key compounds are then transformed via selective ring-forming reactions into heterocyclic scaffolds, each of which possesses suitable functional handles for further derivatizations and palladium-catalyzed cross coupling reactions. The modular nature of this approach enables the facile construction of libraries of polycyclic compounds bearing a broad range of substituents and substitution patterns for biological evaluation. Screening of several compound libraries thus produced has revealed a large subset of compounds that exhibit a broad spectrum of medicinally-relevant activities.
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Affiliation(s)
- James J Sahn
- Department of Chemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX 78712-0165, USA.
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Hardy S, Martin SF. Multicomponent, Mannich-type assembly process for generating novel, biologically-active 2-arylpiperidines and derivatives. Tetrahedron 2014; 70:7142-7157. [PMID: 25267860 PMCID: PMC4175438 DOI: 10.1016/j.tet.2014.06.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A multicomponent, Mannich-type assembly process commencing with commercially available bromobenzaldehydes was sequenced with [3+2] dipolar cycloaddition reactions involving nitrones and azomethine ylides to generate collections of fused, bicyclic scaffolds based on the 2-arylpiperidine subunit. Use of the 4-pentenoyl group, which served both as an activator in the Mannich-type reaction and a readily-cleaved amine protecting group, allowed sub-libraries to be prepared through piperidine N-functionalization and cross-coupling of the aryl bromide. A number of these derivatives displayed biological activities that had not previously been associated with this substructure. Methods were also developed that allowed rapid conversion of these scaffolds to novel, polycyclic dihydroquinazolin-2-ones, 2-imino-1,3-benzothiazinanes, dihydroisoquinolin-3-ones and bridged tetrahydroquinolines.
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Affiliation(s)
- Simon Hardy
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
| | - Stephen F. Martin
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
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18
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Ransborg LK, Overgaard M, Hejmanowska J, Barfüsser S, Jørgensen KA, Albrecht Ł. Asymmetric formation of bridged benzoxazocines through an organocatalytic multicomponent dienamine-mediated one-pot cascade. Org Lett 2014; 16:4182-5. [PMID: 25084456 DOI: 10.1021/ol501882x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An organocatalytic one-pot cascade leading to the stereoselective formation of novel bridged benzoxazocines is presented. The developed methodology is based on the first example of a γ-selective-Mannich-initiated cascade reaction and allows for direct annulation of the bridged benzoxazocines by incorporation of various α,β-unsaturated aldehydes, electron-rich anilines, and electron-deficient salicylaldehydes. The synthetic applicability of the products is demonstrated by relevant transformations.
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19
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Herndon JW. The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2011. Coord Chem Rev 2013. [DOI: 10.1016/j.ccr.2013.05.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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20
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Granger BA, Wang Z, Kaneda K, Fang Z, Martin SF. Multicomponent assembly processes for the synthesis of diverse yohimbine and corynanthe alkaloid analogues. ACS COMBINATORIAL SCIENCE 2013; 15:379-86. [PMID: 23697376 DOI: 10.1021/co400055b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A strategy involving a Mannich-type multicomponent assembly process followed by a 1,3-dipolar cycloaddition has been developed for the rapid and efficient construction of parent heterocyclic scaffolds bearing indole and isoxazolidine rings. These key intermediates were then readily elaborated using well-established protocols for refunctionalization and cross-coupling to access a diverse 180-member library of novel pentacyclic and tetracyclic compounds related to the Yohimbine and Corynanthe alkaloids. Several other new multicomponent assembly processes were developed to access dihydro-β-carboline-fused benzodiazepines, pyrimidinediones, and rutaecarpine derivatives.
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Affiliation(s)
- Brett A. Granger
- Department of Chemistry
and Biochemistry, The Texas Institute for Drug and Diagnostic Development, The University of Texas at Austin, Austin, Texas 78712,
United States
| | - Zhiqian Wang
- Department of Chemistry
and Biochemistry, The Texas Institute for Drug and Diagnostic Development, The University of Texas at Austin, Austin, Texas 78712,
United States
| | - Kyosuke Kaneda
- Department of Chemistry
and Biochemistry, The Texas Institute for Drug and Diagnostic Development, The University of Texas at Austin, Austin, Texas 78712,
United States
| | - Zhenglai Fang
- Department of Chemistry
and Biochemistry, The Texas Institute for Drug and Diagnostic Development, The University of Texas at Austin, Austin, Texas 78712,
United States
| | - Stephen F. Martin
- Department of Chemistry
and Biochemistry, The Texas Institute for Drug and Diagnostic Development, The University of Texas at Austin, Austin, Texas 78712,
United States
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21
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Grafton MW, Farrugia LJ, Sutherland A. Synthesis of Amino-Substituted Indanes and Tetralins via Consecutive Multibond-Forming Tandem Processes. J Org Chem 2013; 78:7199-207. [DOI: 10.1021/jo401182r] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mark W. Grafton
- WestCHEM, School of Chemistry,
The Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Louis J. Farrugia
- WestCHEM, School of Chemistry,
The Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Andrew Sutherland
- WestCHEM, School of Chemistry,
The Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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22
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Martin SF. Strategies for the Synthesis of Alkaloids and Novel Nitrogen Heterocycles. ADVANCES IN HETEROCYCLIC CHEMISTRY 2013. [DOI: 10.1016/b978-0-12-408100-0.00003-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
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23
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Sahn JJ, Martin SF. Expedient synthesis of norbenzomorphan library via multicomponent assembly process coupled with ring-closing reactions. ACS COMBINATORIAL SCIENCE 2012; 14:496-502. [PMID: 22857149 DOI: 10.1021/co300068a] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A 124-member norbenzomorphan library has been prepared utilizing a novel multicomponent assembly process (MCAP) followed by a variety of ring-closing reactions to generate norbenzomorphan scaffolds that were readily derivatized via a series of aryl halide cross-coupling and nitrogen functionalization reactions. Biological screening has revealed some novel activities that have not been previously associated with this class of compounds.
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Affiliation(s)
- James J. Sahn
- Department of Chemistry and Biochemistry,
The Texas
Institute for Drug and Diagnostic Development, The University of Texas, Austin, Texas 78712, United States
| | - Stephen F. Martin
- Department of Chemistry and Biochemistry,
The Texas
Institute for Drug and Diagnostic Development, The University of Texas, Austin, Texas 78712, United States
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24
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Donald JR, Wood RR, Martin SF. Application of a sequential multicomponent assembly process/huisgen cycloaddition strategy to the preparation of libraries of 1,2,3-triazole-fused 1,4-benzodiazepines. ACS COMBINATORIAL SCIENCE 2012; 14:135-43. [PMID: 22273436 DOI: 10.1021/co2002087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A strategy featuring a multicomponent assembly process followed by an intramolecular azide-alkyne dipolar (Huisgen) cycloaddition was implemented for the facile synthesis of three different 1,2,3-triazolo-1,4-benzodiazepine scaffolds. A diverse library of 170 compounds derived from these scaffolds was then created through N-functionalizations, palladium-catalyzed cross-coupling reactions, and several applications of α-aminonitrile chemistry.
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Affiliation(s)
- James R. Donald
- Department of Chemistry and Biochemistry, The Texas
Institute for Drug and Diagnostic Development, The University of Texas, Austin, Texas 78712, United States
| | - Rebekah R. Wood
- Department of Chemistry and Biochemistry, The Texas
Institute for Drug and Diagnostic Development, The University of Texas, Austin, Texas 78712, United States
| | - Stephen F. Martin
- Department of Chemistry and Biochemistry, The Texas
Institute for Drug and Diagnostic Development, The University of Texas, Austin, Texas 78712, United States
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25
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Wang Z, Kaneda K, Fang Z, Martin SF. Diversity Oriented Synthesis: Concise Entry to Novel Derivatives of Yohimbine and Corynanthe Alkaloids. Tetrahedron Lett 2012; 53:477-479. [PMID: 22544982 PMCID: PMC3335433 DOI: 10.1016/j.tetlet.2011.10.115] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
A novel MCAP-cycloaddition sequence has been applied to the facile synthesis of β-carboline intermediates to gain rapid access to novel derivatives of yohimbine-like and corynanthe-like compounds that may be easily diversified by cross-coupling reactions and N-derivatizations to generate small compound libraries.
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Affiliation(s)
- Zhiqian Wang
- Department of Chemistry and Biochemistry and Texas Institute for Drug and Diagnostic Development, The University of Texas, Austin, TX, 78712, USA
| | - Kyosuke Kaneda
- Department of Chemistry and Biochemistry and Texas Institute for Drug and Diagnostic Development, The University of Texas, Austin, TX, 78712, USA
| | - Zhenglai Fang
- Department of Chemistry and Biochemistry and Texas Institute for Drug and Diagnostic Development, The University of Texas, Austin, TX, 78712, USA
| | - Stephen F. Martin
- Department of Chemistry and Biochemistry and Texas Institute for Drug and Diagnostic Development, The University of Texas, Austin, TX, 78712, USA
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26
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Granger BA, Kaneda K, Martin SF. Libraries of 2,3,4,6,7,11b-hexahydro-1H-pyrido[2,1-a]isoquinolin-2-amine derivatives via a multicomponent assembly process/1,3-dipolar cycloaddition strategy. ACS COMBINATORIAL SCIENCE 2012; 14:75-9. [PMID: 22040015 DOI: 10.1021/co2001636] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A Mannich-type multicomponent assembly process/1,3-dipolar cycloaddition strategy has been developed for the rapid and efficient construction of a parent tetrahydroisoquinoline fused isoxazolidine scaffold, which was subsequently functionalized using well-established protocols to access a diverse 70-membered library of novel 2,3,4,6,7,11b-hexahydro-1H-pyrido[2,1-a]isoquinoline-2-amine derivatives.
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Affiliation(s)
- Brett A. Granger
- Department of Chemistry and Biochemistry, The Texas
Institute for Drug and Diagnostic Development, The University of Texas, Austin, Texas 78712, United States
| | - Kyosuke Kaneda
- Department of Chemistry and Biochemistry, The Texas
Institute for Drug and Diagnostic Development, The University of Texas, Austin, Texas 78712, United States
| | - Stephen F. Martin
- Department of Chemistry and Biochemistry, The Texas
Institute for Drug and Diagnostic Development, The University of Texas, Austin, Texas 78712, United States
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27
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Sahn JJ, Martin SF. Facile Syntheses of Substituted, Conformationally-Constrained Benzoxazocines and Benzazocines via Sequential Multicomponent Assembly and Cyclization. Tetrahedron Lett 2011; 52:6855-6858. [PMID: 22711939 PMCID: PMC3375694 DOI: 10.1016/j.tetlet.2011.10.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A multicomponent assembly process (MCAP) was utilized to prepare versatile intermediates that are suitably functionalized for subsequent cyclizations via Ullmann and Heck reactions to efficiently construct substituted 2,6-methanobenzo[b][1,5]oxazocines and 1,6-methanobenzo[c]azocines, respectively. The intramolecular Ullmann cyclization was conducted in tandem with an intermolecular arylation that enabled the rapid syntheses of a number of O-functionalized methanobenzoxazocines.
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Affiliation(s)
- James J Sahn
- Department of Chemistry and Biochemistry and Texas Institute for Drug and Diagnostic Development, The University of Texas, Austin, TX, 78712, USA
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28
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Donald JR, Granger BA, Hardy S, Sahn JJ, Martin SF. APPLICATIONS OF MULTICOMPONENT ASSEMBLY PROCESSES TO THE FACILE SYNTHESES OF DIVERSELY FUNCTIONALIZED NITROGEN HETEROCYCLES. HETEROCYCLES 2011; 84:1089-1112. [PMID: 22451742 DOI: 10.3987/com-11-s(p)92] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Several multicomponent assembly processes have been developed for the synthesis of intermediates that may be elaborated by a variety of cyclizations to generate a diverse array of highly functionalized heterocycles from readily-available starting materials. The overall approach enables the efficient preparation of libraries of small molecules derived from fused, privileged scaffolds.
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Affiliation(s)
- James R Donald
- Department of Chemistry and Biochemistry and Texas Institute for Drug and Diagnostics Development, The University of Texas at Austin, Austin, Texas 78712, United States
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29
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Granger BA, Kaneda K, Martin SF. Multicomponent assembly strategies for the synthesis of diverse tetrahydroisoquinoline scaffolds. Org Lett 2011; 13:4542-5. [PMID: 21834504 DOI: 10.1021/ol201739u] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several novel multicomponent assembly processes have been developed for the rapid and efficient assembly of various heterocyclic scaffolds bearing a tetrahydroisoquinoline core, each of which allows for facile derivatization to access a diverse array of compounds. This work led to the serendipitous discovery of a new method for the synthesis of a fused quinazolone ring system, which was applied to a one-step total synthesis of the quinazolinocarboline alkaloid rutaecarpine.
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Affiliation(s)
- Brett A Granger
- Department of Chemistry and Biochemistry, The Texas Institute for Drug and Diagnostic Development, The University of Texas at Austin, Austin, Texas 78712, USA
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30
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Hardy S, Martin SF. Multicomponent assembly and diversification of novel heterocyclic scaffolds derived from 2-arylpiperidines. Org Lett 2011; 13:3102-5. [PMID: 21598984 PMCID: PMC3116656 DOI: 10.1021/ol201010s] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A collection of structurally diverse, polyheterocyclic scaffolds comprising a 2-arylpiperidine subunit were synthesized using a Mannich-type multicomponent assembly process, followed by appropriately sequenced ring-forming reactions. An improved procedure for removal of N-4-pentenoyl groups was developed; one-pot sequences for tandem urea/thiourea formation and cyclization and tandem enolate arylation/alkylation were discovered. A novel entry to bridged tetrahydroquinoline scaffolds exploiting A(1,3) strain was also invented. Derivatization of several scaffolds was achieved by cross-coupling and N-functionalization.
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Affiliation(s)
- Simon Hardy
- Department of Chemistry and Biochemistry, The Texas Institute for Drug and Diagnostic Development, The University of Texas at Austin, Austin Texas 78712
| | - Stephen F. Martin
- Department of Chemistry and Biochemistry, The Texas Institute for Drug and Diagnostic Development, The University of Texas at Austin, Austin Texas 78712
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