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Reddy Vakiti J, Hanessian S. Total Synthesis and Stereochemical Confirmation of (-)-Olivil, (+)-Cycloolivil, (-)-Alashinols F and G, (+)-Cephafortin A, and Their Congeners: Filling in Biosynthetic Gaps. Org Lett 2020; 22:3345-3350. [PMID: 32293189 DOI: 10.1021/acs.orglett.0c00773] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
For the first time, we describe the stereocontrolled total syntheses of olivil, cephafortin A, 4-des-O-methyl-4-O-rhamnosyl cephafortin A, and alashinol F from a common precursor using a combination of chemoenzymatic and biomimetic methods for the systematic introduction of functional groups on three vicinal stereogenic carbon atoms. We revised the previously assigned stereochemistry of (+)-cephafortin A, which was reported as the enantiomer. Natural and unnatural congeners provide insights into the biogenetic interrelations of members of this family.
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Hocine S, Berger G, Hanessian S. Design and Synthesis of Backbone-Fused, Conformationally Constrained Morpholine-Proline Chimeras. J Org Chem 2020; 85:4237-4247. [PMID: 32134267 DOI: 10.1021/acs.joc.9b03413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We report the synthesis of two novel bridged morpholine-proline chimeras 4 and 5, which represent rigid conformationally locked three-dimensional structures wherein the lone pairs of electrons on oxygen and nitrogen are oriented in spatially different "east-west" and "north-west" directions, respectively. In combination with the presence of a carboxylic acid, the electronic features of these compounds may be useful in the context of peptidomimetic design of biologically relevant compounds. Quantitative estimates of the basicity of the nitrogen atoms were obtained using conceptual density functional theory analysis.
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Salinas JC, Seth PP, Hanessian S. Design And Synthesis Of An Azabicyclic Nucleoside Phosphoramidite For Oligonucleotide Antisense Constructs. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2019; 39:384-406. [PMID: 31380707 DOI: 10.1080/15257770.2019.1646916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We report the synthesis and biophysical evaluation of an azabicycle dinucleotide with restricted γ, β, and ε torsion angles, featuring the introduction of a piperidine ring that locks the conformation of the nucleoside into an RNA-type nucleic acid. The conceptual basis of the design is predicated upon the notion that the conformation of the phosphate group linking two RNA nucleotides can be approximated with an azabicyclic phosphoramidite which may also benefit from a unique stereoelectronic effect.
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Duchamp E, Simard BD, Hanessian S. Reductive Fragmentation of Tetrazoles: Mechanistic Insights and Applications toward the Stereocontrolled Synthesis of 2,6-Polysubstituted Morpholines. Org Lett 2019; 21:6593-6596. [DOI: 10.1021/acs.orglett.9b01842] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Kubiniok P, Finicle BT, Piffaretti F, McCracken AN, Perryman M, Hanessian S, Edinger AL, Thibault P. Dynamic Phosphoproteomics Uncovers Signaling Pathways Modulated by Anti-oncogenic Sphingolipid Analogs. Mol Cell Proteomics 2019; 18:408-422. [PMID: 30482847 PMCID: PMC6398214 DOI: 10.1074/mcp.ra118.001053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/23/2018] [Indexed: 12/31/2022] Open
Abstract
The anti-neoplastic sphingolipid analog SH-BC-893 starves cancer cells to death by down-regulating cell surface nutrient transporters and blocking lysosomal trafficking events. These effects are mediated by the activation of protein phosphatase 2A (PP2A). To identify putative PP2A substrates, we used quantitative phosphoproteomics to profile the temporal changes in protein phosphorylation in FL5.12 cells following incubation with SH-BC-893 or the specific PP2A inhibitor LB-100. These analyses enabled the profiling of more than 15,000 phosphorylation sites, of which 958 sites on 644 proteins were dynamically regulated. We identified 114 putative PP2A substrates including several nutrient transporter proteins, GTPase regulators (e.g. Agap2, Git1), and proteins associated with actin cytoskeletal remodeling (e.g. Vim, Pxn). To identify SH-BC-893-induced cell signaling events that disrupt lysosomal trafficking, we compared phosphorylation profiles in cells treated with SH-BC-893 or C2-ceramide, a non-vacuolating sphingolipid that does not impair lysosomal fusion. These analyses combined with functional assays uncovered the differential regulation of Akt and Gsk3b by SH-BC-893 (vacuolating) and C2-ceramide (non-vacuolating). Dynamic phosphoproteomics of cells treated with compounds affecting PP2A activity thus enabled the correlation of cell signaling with phenotypes to rationalize their mode of action.
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Rico L, Hanessian S. Synthesis of 1',2'-methano-2',3'-dideoxynucleosides as potential antivirals. Bioorg Med Chem Lett 2018; 29:597-600. [PMID: 30612845 DOI: 10.1016/j.bmcl.2018.12.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/20/2018] [Accepted: 12/22/2018] [Indexed: 02/05/2023]
Abstract
The synthesis of constrained nucleosides has become an important tool to understand the SAR in the interaction between biological and synthetic nucleotides in the context of antisense oligonucleotide therapy. The incorporation of a cyclopropane into a furanose ring of a nucleoside induces some degree of constrain without affecting significantly the steric environment of a nucleoside. Here, we report a new, short and stereocontrolled synthesis of two constrained nucleosides analogues, 1',2'- methano-2',3'-dideoxyuridine 9, and the corresponding cytidine analog 12. X-ray crystallography revealed that the furanose ring in the constrained uridine and cytidine analogues was flattened with virtual loss of pseudorotation. The phosphoramidate esters of the novel constrained uridine and cytidine nucleosides, intended as prodrugs, were tested in cell-based assays for viral replication across the herpes virus family and HIV inhibition courtesy of Merck laboratories, Rahway. They were also tested in antiproliferative assays against colorectal and melanoma cell lines. Unfortunately, none of the compounds showed activity in these assays.
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Garsi JB, Sernissi L, Vece V, Hanessian S, McCracken AN, Simitian G, Edinger AL. In search of constrained FTY720 and phytosphingosine analogs as dual acting anticancer agents targeting metabolic and epigenetic pathways. Eur J Med Chem 2018; 159:217-242. [PMID: 30292898 PMCID: PMC6217821 DOI: 10.1016/j.ejmech.2018.09.043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/13/2018] [Accepted: 09/14/2018] [Indexed: 01/04/2023]
Abstract
A series of compounds containing pyrrolidine and pyrrolizidine cores with appended hydrophobic substituents were prepared as constrained analogs of FTY720 and phytosphingosine. The effect of these compounds on the viability of cancer cells, on downregulation of the nutrient transport systems, and on their ability to cause vacuolation was studied. An attempt to inhibit HDACs with some phosphate esters of our analogs was thwarted by our failure to reproduce the reported inhibitory action of FTY720-phosphate.
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Salinas JC, Yu J, Østergaard M, Seth PP, Hanessian S. Conception and Synthesis of Oxabicyclic Nucleoside Phosphonates as Internucleotidic Phosphate Surrogates in Antisense Oligonucleotide Constructs. Org Lett 2018; 20:5296-5299. [PMID: 30146887 DOI: 10.1021/acs.orglett.8b02233] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The stereocontrolled synthesis of a novel oxabicyclic nucleoside phosphonate comprising a perhydrofuropyran core unit was achieved. It was incorporated in an oligonucleotide sequence as a 5'-3' phosphonate-phosphate insert, and the stability properties of the resulting duplex were measured. The oxabicyclic nucleoside framework was designed so as to restrict rotation around angles γ, δ, and ε of a natural nucleoside.
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Maertens G, Saavedra OM, Vece V, Reyes MAV, Hocine S, Öney E, Goument B, Mirguet O, Le Tiran A, Gloanec P, Hanessian S. Design and synthesis of bridged piperidine and piperazine isosteres. Bioorg Med Chem Lett 2018; 28:2627-2630. [PMID: 29937060 DOI: 10.1016/j.bmcl.2018.06.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 06/17/2018] [Indexed: 01/11/2023]
Abstract
We have developed versatile methods toward the synthesis of a variety of piperidine/piperazine bridged isosteres of pridopidine. The compounds were assessed against the D2 receptor in agonist and antagonist modes and against the D4 receptor in agonist mode. hERG Binding and the ADME profiles were studied.
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Kanazawa H, Saavedra OM, Maianti JP, Young SA, Izquierdo L, Smith TK, Hanessian S, Kondo J. Structure-Based Design of a Eukaryote-Selective Antiprotozoal Fluorinated Aminoglycoside. ChemMedChem 2018; 13:1541-1548. [PMID: 29766661 DOI: 10.1002/cmdc.201800166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 05/15/2018] [Indexed: 11/12/2022]
Abstract
Aminoglycosides (AG) are antibiotics that lower the accuracy of protein synthesis by targeting a highly conserved RNA helix of the ribosomal A-site. The discovery of AGs that selectively target the eukaryotic ribosome, but lack activity in prokaryotes, are promising as antiprotozoals for the treatment of neglected tropical diseases, and as therapies to read-through point-mutation genetic diseases. However, a single nucleobase change A1408G in the eukaryotic A-site leads to negligible affinity for most AGs. Herein we report the synthesis of 6'-fluorosisomicin, the first 6'-fluorinated aminoglycoside, which specifically interacts with the protozoal cytoplasmic rRNA A-site, but not the bacterial A-site, as evidenced by X-ray co-crystal structures. The respective dispositions of 6'-fluorosisomicin within the bacterial and protozoal A-sites reveal that the fluorine atom acts only as a hydrogen-bond acceptor to favorably interact with G1408 of the protozoal A-site. Unlike aminoglycosides containing a 6'-ammonium group, 6'-fluorosisomicin cannot participate in the hydrogen-bonding pattern that characterizes stable pseudo-base-pairs with A1408 of the bacterial A-sites. Based on these structural observations it may be possible to shift the biological activity of aminoglycosides to act preferentially as antiprotozoal agents. These findings expand the repertoire of small molecules targeting the eukaryotic ribosome and demonstrate the usefulness of fluorine as a design element.
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Vece V, Jakkepally S, Hanessian S. Total Synthesis and Absolute Stereochemical Assignment of the Insecticidal Metabolites Yaequinolones J1 and J2. Org Lett 2018; 20:4277-4280. [PMID: 29975546 DOI: 10.1021/acs.orglett.8b01701] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A highly stereocontrolled total synthesis of (-)-yaequinolone J1 and (+)-yaequinolone J2 was accomplished using an Evans auxiliary to establish a syn-diol unit in an acyclic appendage to a preformed benzopyran core bearing a homoprenyl group. The first total synthesis of a complex member of this family of 3,4-dioxygenated 3,4-dihydro 4-aryl quinolin-2-(1 H)-ones also allowed the assignment of absolute stereochemistry, thereby suggesting the same for several members of this family of biogenetically related alkaloids hitherto reported with relative configurations of stereogenic carbons for some and absolute assignments relying on empirical data for others.
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Rico L, Østergaard ME, Bell M, Seth PP, Hanessian S. Studies directed toward the asialoglycoprotein receptor mediated delivery of 5-fluoro-2'-deoxyuridine for hepatocellular carcinoma. Bioorg Med Chem Lett 2018; 28:2652-2654. [PMID: 30042045 DOI: 10.1016/j.bmcl.2018.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/01/2018] [Indexed: 01/12/2023]
Abstract
The anticancer nucleoside 5-fluoro 2'-deoxyuridine-5'-phosphate (5-FdU-P) was attached via an amide chain linker to a triantennary GalNAc cluster as a means to deliver the drug to hepatic cells that recognize the amino sugar units.
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Chénard É, Cusson JP, Hanessian S. Catalytic asymmetric Friedel–Crafts synthesis of 1,1′-diaryl-2-substituted 4-pentenes enables stereoselective access to functionalized tetrahydronaphthalenes. CAN J CHEM 2017. [DOI: 10.1139/cjc-2017-0393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A series of electron-rich arenes were reacted with 1-alkyl or 1-aryl 1′-allyl benzylic alcohols to give the corresponding 1,1′-diarylalkanes, in the presence of Lewis and Brønsted acids as catalysts. In the presence of HBF4, 1,1′-diarylalkanes containing an allylic chain were shown to form tetrahydronaphthalenes through a rearrangement involving spirocyclic intermediates. The mechanism of the cyclization is discussed.
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Chen B, Berger G, Hanessian S. Metal Coordination Controlled and Bifunctional H-Bonded Catalysis in Stereoselective Intramolecular Aldol Cyclizations toward Carbocyclic Tertiary β-Ketols. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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40
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McCracken AN, McMonigle RJ, Tessier J, Fransson R, Perryman MS, Chen B, Keebaugh A, Selwan E, Barr SA, Kim SM, Roy SG, Liu G, Fallegger D, Sernissi L, Brandt C, Moitessier N, Snider AJ, Clare S, Müschen M, Huwiler A, Kleinman MT, Hanessian S, Edinger AL. Phosphorylation of a constrained azacyclic FTY720 analog enhances anti-leukemic activity without inducing S1P receptor activation. Leukemia 2017; 31:669-677. [PMID: 27573555 PMCID: PMC5332311 DOI: 10.1038/leu.2016.244] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/19/2016] [Accepted: 08/22/2016] [Indexed: 02/07/2023]
Abstract
The frequency of poor outcomes in relapsed leukemia patients underscores the need for novel therapeutic approaches. The Food and Drug Administration-approved immunosuppressant FTY720 limits leukemia progression by activating protein phosphatase 2A and restricting nutrient access. Unfortunately, FTY720 cannot be re-purposed for use in cancer patients due to on-target toxicity associated with S1P receptor activation at the elevated, anti-neoplastic dose. Here we show that the constrained azacyclic FTY720 analog SH-RF-177 lacks S1P receptor activity but maintains anti-leukemic activity in vitro and in vivo. SH-RF-177 was not only more potent than FTY720, but killed via a distinct mechanism. Phosphorylation is dispensable for FTY720's anti-leukemic actions. However, chemical biology and genetic approaches demonstrated that the sphingosine kinase 2 (SPHK2)-mediated phosphorylation of SH-RF-177 led to engagement of a pro-apoptotic target and increased potency. The cytotoxicity of membrane-permeant FTY720 phosphonate esters suggests that the enhanced potency of SH-RF-177 stems from its more efficient phosphorylation. The tight inverse correlation between SH-RF-177 IC50 and SPHK2 mRNA expression suggests a useful biomarker for SH-RF-177 sensitivity. In summary, these studies indicate that FTY720 analogs that are efficiently phosphorylated but fail to activate S1P receptors may be superior anti-leukemic agents compared to compounds that avoid cardiotoxicity by eliminating phosphorylation.
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Chattopadhyay AK, Hanessian S. Recent Progress in the Chemistry of Daphniphyllum Alkaloids †. Chem Rev 2017; 117:4104-4146. [PMID: 28205435 DOI: 10.1021/acs.chemrev.6b00412] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Daphniphyllum is an evergreen species known since 1826. After initial systematic investigations, more than 320 members of this family have been isolated, which comprise complex and fascinating structures. Unique azapolycyclic architectures containing one or more quaternary stereocenters render these alkaloids synthetically challenging. This review covers efforts toward the synthesis of Daphniphyllum alkaloids spanning the period from 2005 to the beginning of 2016, including reported biological activities as well as the isolation of new members of this genus.
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Kim SM, Roy SG, Chen B, Nguyen TM, McMonigle RJ, McCracken AN, Zhang Y, Kofuji S, Hou J, Selwan E, Finicle BT, Nguyen TT, Ravi A, Ramirez MU, Wiher T, Guenther GG, Kono M, Sasaki AT, Weisman LS, Potma EO, Tromberg BJ, Edwards RA, Hanessian S, Edinger AL. Targeting cancer metabolism by simultaneously disrupting parallel nutrient access pathways. J Clin Invest 2016; 126:4088-4102. [PMID: 27669461 PMCID: PMC5096903 DOI: 10.1172/jci87148] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 08/16/2016] [Indexed: 12/23/2022] Open
Abstract
Oncogenic mutations drive anabolic metabolism, creating a dependency on nutrient influx through transporters, receptors, and macropinocytosis. While sphingolipids suppress tumor growth by downregulating nutrient transporters, macropinocytosis and autophagy still provide cancer cells with fuel. Therapeutics that simultaneously disrupt these parallel nutrient access pathways have potential as powerful starvation agents. Here, we describe a water-soluble, orally bioavailable synthetic sphingolipid, SH-BC-893, that triggers nutrient transporter internalization and also blocks lysosome-dependent nutrient generation pathways. SH-BC-893 activated protein phosphatase 2A (PP2A), leading to mislocalization of the lipid kinase PIKfyve. The concomitant mislocalization of the PIKfyve product PI(3,5)P2 triggered cytosolic vacuolation and blocked lysosomal fusion reactions essential for LDL, autophagosome, and macropinosome degradation. By simultaneously limiting access to both extracellular and intracellular nutrients, SH-BC-893 selectively killed cells expressing an activated form of the anabolic oncogene Ras in vitro and in vivo. However, slower-growing, autochthonous PTEN-deficient prostate tumors that did not exhibit a classic Warburg phenotype were equally sensitive. Remarkably, normal proliferative tissues were unaffected by doses of SH-BC-893 that profoundly inhibited tumor growth. These studies demonstrate that simultaneously blocking parallel nutrient access pathways with sphingolipid-based drugs is broadly effective and cancer selective, suggesting a potential strategy for overcoming the resistance conferred by tumor heterogeneity.
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Giacometti RD, Salinas JC, Østergaard ME, Swayze EE, Seth PP, Hanessian S. Design, synthesis, and duplex-stabilizing properties of conformationally constrained tricyclic analogues of LNA. Org Biomol Chem 2016; 14:2034-40. [PMID: 26765794 DOI: 10.1039/c5ob02576a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The design, synthesis and biophysical evaluation of two highly-constrained tricyclic analogues of locked nucleic acid (LNA), which restrict rotation around the C4'-C5'-exocyclic bond (torsion angle γ) and enhance hydrophobicity in the minor groove and along the major groove, are reported. A structural model that provides insights into the sugar-phosphate backbone conformations required for efficient hybridization to complementary nucleic acids is also presented.
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Chattopadhyay AK, Berger G, Hanessian S. Strategies toward the Total Synthesis of Calyciphylline B-type Alkaloids: A Computational Perspective Aided by DFT Analysis. J Org Chem 2016; 81:5074-86. [PMID: 27251014 DOI: 10.1021/acs.joc.6b00638] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Herein we describe synthetic efforts toward the total synthesis of calyciphylline B-type alkaloids. In the process, we disclose a detailed DFT study of equilibrium geometries and transition states that explains the stereochemical outcome during the formation of critical intermediates. X-ray crystallographic analysis reveals interesting conformational features in the naturally occurring deoxycalyciphylline B and its synthetic congeners.
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St-Pierre G, Hanessian S. Solution and Solid-Phase Stereocontrolled Synthesis of 1,2-cis-Glycopyranosides with Minimally Protected Glycopyranosyl Donors Catalyzed by BF3-N,N-Dimethylformamide Complex. Org Lett 2016; 18:3106-9. [PMID: 27301355 DOI: 10.1021/acs.orglett.6b01263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Methods are described for the stereoselective synthesis of 1,2-cis glycopyranosides in the d-galacto, d-gluco, and 2-azido-2-deoxy-d-glucopyranoside series utilizing minimally protected (3-bromo-2-pyridyloxy) β-d-glycopyranosyl donors in the presence of BF3-N,N-dimethylformamide (DMF) as a catalyst and a variety of alcohol acceptors relying on the "remote activation concept". Precursors to antifreeze glycopeptide components are synthesized in excellent yields and high α/β ratios. The method is adaptable to one-pot sequential glycosidation as well as to solid-supported synthesis giving access to diverse sets of minimally protected α-d-glycopyranosides as major products.
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Hanessian S, St-Pierre G, Dafik L, Klegraf E. Stereocontrolled Synthesis of Phenolic α-d-Glycopyranosides. SYNTHESIS-STUTTGART 2016. [DOI: 10.1055/s-0035-1561461] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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47
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St-Pierre G, Pal S, Østergaard ME, Zhou T, Yu J, Tanowitz M, Seth PP, Hanessian S. Synthesis and biological evaluation of sialyl-oligonucleotide conjugates targeting leukocyte B trans-membranal receptor CD22 as delivery agents for nucleic acid drugs. Bioorg Med Chem 2016; 24:2397-2409. [PMID: 27117693 DOI: 10.1016/j.bmc.2016.03.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/16/2016] [Accepted: 03/27/2016] [Indexed: 01/27/2023]
Abstract
Antisense oligonucleotides (ASOs) modified with ligands which target cell surface receptors have the potential to significantly improve potency in the target tissue. This has recently been demonstrated using triantennary N-acetyl d-galactosamine conjugated ASOs. CD22 is a cell surface receptor expressed exclusively on B cells thus presenting an attractive target for B cell specific delivery of drugs. Herein, we reported the synthesis of monovalent and trivalent ASO conjugates with biphenylcarbonyl (BPC) modified sialic acids and their study as ASO delivery agents into B cells. CD22 positive cells exhibited reduced potency when treated with ligand modified ASOs and mechanistic examination suggested reduced uptake into cells potentially as a result of sequestration of ASO by other cell-surface proteins.
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Büschleb M, Dorich S, Hanessian S, Tao D, Schenthal KB, Overman LE. Synthetic Strategies toward Natural Products Containing Contiguous Stereogenic Quaternary Carbon Atoms. Angew Chem Int Ed Engl 2016; 55:4156-86. [PMID: 26836448 PMCID: PMC4865016 DOI: 10.1002/anie.201507549] [Citation(s) in RCA: 251] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Indexed: 11/06/2022]
Abstract
Strategies for the total synthesis of complex natural products that contain two or more contiguous stereogenic quaternary carbon atoms in their intricate structures are reviewed with 12 representative examples. Emphasis has been put on methods to create quaternary carbon stereocenters, including syntheses of the same natural product by different groups, thereby showcasing the diversity of thought and individual creativity. A compendium of selected natural products containing two or more contiguous stereogenic quaternary carbon atoms and key reactions in their total or partial syntheses is provided in the Supporting Information.
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Chattopadhyay AK, Hanessian S. Cyclic enaminones. Part I: stereocontrolled synthesis using diastereoselective and catalytic asymmetric methods. Chem Commun (Camb) 2016; 51:16437-49. [PMID: 26490402 DOI: 10.1039/c5cc05891k] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cyclic enaminones are versatile intermediates to construct a variety of azacyclic frameworks and have been widely used in alkaloid synthesis. Here, we summarize three approaches for stereoselective syntheses of cyclic enaminones and their functionalized derivatives. These include chiral substrates (chirons) as starting materials, syntheses employing non-catalytic (stoichiometric) reagents, and catalytic asymmetric methods.
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50
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Chattopadhyay AK, Hanessian S. Cyclic enaminones. Part II: applications as versatile intermediates in alkaloid synthesis. Chem Commun (Camb) 2016; 51:16450-67. [PMID: 26490499 DOI: 10.1039/c5cc05892a] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Among many other strategies, the enaminone approach is an important strategy to construct and diversify the azacyclic core in various alkaloids syntheses. In this brief review we discuss the application of cyclic enaminones as building blocks, as well as potential intermediates in the total synthesis of selected alkaloids.
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