76
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Guranova N, Kantin G, Dar'in D, Krasavin M. Diazo Glutaconimides: an Unexplored Type of Heterocyclic α‐Diazocarbonyl Compounds Conveniently Evolved into Pyridine‐2,6(1
H
,3
H
)‐diones and Oxazolo[5,4‐
b
]pyridin‐5(4
H
)‐ones. European J Org Chem 2020. [DOI: 10.1002/ejoc.202001451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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77
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Dar’in D, Krasavin M, Bubyrev A, Kantin G. CH-Diazomethane Sulfonamides Generated in Situ for Intramolecular [3+2] Cycloaddition of Alkynes: An Entry into Novel Pyrazole-Fused Five-Membered Sultams. SYNTHESIS-STUTTGART 2020. [DOI: 10.1055/a-1336-6857] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
AbstractPreviously reported CH-diazomethane sulfonamides carrying various propargylic groups are generated in situ from their acetyl precursors. Without purification, these compounds undergo a slow, albeit clean and efficient, intramolecular [3+2] cycloaddition to give pyrazole-fused five-membered sultams. The latter are the first analogues of medicinally important (hetero)arene-fused five-membered sultams containing a five-membered nitrogenous heterocycle. The newly introduced scaffold can be further elaborated into N-arylated derivatives using the Chan–Evans–Lam protocol. The resulting compounds incorporate more than one privileged moiety and are highly suitable for interrogation of protein targets via biological screening.
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78
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Dar'in D, Kantin G, Bakulina O, Inyutina A, Chupakhin E, Krasavin M. Spirocyclizations Involving Oxonium Ylides Derived from Cyclic α-Diazocarbonyl Compounds: An Entry into 6-Oxa-2-azaspiro[4.5]decane Scaffold. J Org Chem 2020; 85:15586-15599. [PMID: 33226243 DOI: 10.1021/acs.joc.0c02356] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
New types of cyclic diazo compounds capable of Rh(II)-catalyzed spirocyclizations with tetrahydrofuran have been discovered. The formation of the spirocyclic framework is thought to proceed via the formation of Rh(II) carbene species followed by interaction with the Lewis basic oxygen atom of tetrahydrofuran to give oxonium ylide species. The latter evolves predominantly via the Stevens type rearrangement leading to an [n + 1] ring expansion of the tetrahydrofuran moiety, which results in the formation of a medicinally relevant 6-oxa-2-azaspiro[4.5]decane scaffold. The spirocyclization process was often observed in competition with mechanistically distinct C-H insertion into a tetrahydrofuran molecule. This competing process gave compounds based on the 3-(tetrahydrofur-2-yl)pyrrolidine scaffold, which are also relevant from the medicinal chemistry standpoint. These findings enrich the available arsenal of metal-catalyzed spirocyclization methods based on the use of cyclic diazo compounds.
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79
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Lukin A, Bakholdina A, Zhurilo N, Onopchenko O, Zhuravel E, Zozulya S, Gureev M, Safrygin A, Krasavin M. Exploration of the nitrogen heterocyclic periphery around the core of the advanced FFA1 agonist fasiglifam (TAK-875). Arch Pharm (Weinheim) 2020; 354:e2000275. [PMID: 33270252 DOI: 10.1002/ardp.202000275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/06/2020] [Accepted: 11/13/2020] [Indexed: 11/06/2022]
Abstract
Three types of heterocyclic moieties-piperidines fused to a heteroaromatic moiety-were explored as potential periphery motifs for the pharmacophoric core of fasiglifam (TAK-875), with fasiglifam being the most advanced agonist of free fatty acid receptor 1, a promising target for therapeutic intervention in type 2 diabetes. Several observed structure-activity relationship trends were corroborated by in silico docking results. Balanced selection based on potency and Caco-2 permeability advanced six compounds to cellular efficacy tests (glucose-stimulated insulin secretion in rat insulinoma INS1E cells). This led to the nomination of compound 16a (LK1408, 3-[4-({4-[(3-{[(2-fluorobenzyl)oxy]methyl}-1-methyl-1,4,6,7-tetrahydro-5H-pyrazolo[4,3-c]pyridin-5-yl)methyl]benzyl}oxy)phenyl]propanoic acid hydrochloride) as the lead for further development.
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80
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Krasavin M, Kalinin S, Sharonova T, Supuran CT. Inhibitory activity against carbonic anhydrase IX and XII as a candidate selection criterion in the development of new anticancer agents. J Enzyme Inhib Med Chem 2020; 35:1555-1561. [PMID: 32746643 PMCID: PMC7470080 DOI: 10.1080/14756366.2020.1801674] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 07/21/2020] [Indexed: 12/19/2022] Open
Abstract
Analysis of the literature data reveals that while inhibition of cancer-related carbonic anhydrase IX and XII isoforms continues to be an important enrichment factor for designing anticancer agent development libraries, exclusive reliance on the in vitro inhibition of these two recombinant isozymes in nominating candidate compounds for evaluation of their effects on cancer cells may lead not only to identifying numerous compounds devoid of the desired cellular efficacy but also to overlooking many promising candidates which may not display the best potency in biochemical inhibition assay. However, SLC-0111, now in phase Ib/II clinical trials, was developed based on the excellent agreement between the in vitro, in vivo and more recently, in-patient data.
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81
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Krasavin M, Kalinin S, Zozulya S, Gryniukova A, Borysko P, Angeli A, Supuran CT. Screening of benzenesulfonamide in combination with chemically diverse fragments against carbonic anhydrase by differential scanning fluorimetry. J Enzyme Inhib Med Chem 2020; 35:306-310. [PMID: 31797704 PMCID: PMC6896451 DOI: 10.1080/14756366.2019.1698562] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 11/21/2019] [Accepted: 11/21/2019] [Indexed: 11/11/2022] Open
Abstract
The differential scanning fluorimetry (DSF) screening of 5.692 fragments in combination with benzenesulfonamide (BSA) against bovine carbonic anhydrase (bCA) delivered >100 hits that either caused, on their own, a significant thermal shift (ΔTm, °C) in the protein melting temperature or significantly influenced the thermal shift observed for BSA alone. Three hits based on 1,2,3-triazole moiety represent the periphery of the recently reported potent inhibitors of hCA II, IX and XII which were efficacious in vivo. Such a re-discovery of suitable BSA periphery essentially validates the new fragment-based approach to the discovery of future CAIs. Structures of other validated fragment hits are reported.
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82
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Burianova V, Kalinin S, Supuran CT, Krasavin M. Radiotracers for positron emission tomography (PET) targeting tumour-associated carbonic anhydrase isoforms. Eur J Med Chem 2020; 213:113046. [PMID: 33303236 DOI: 10.1016/j.ejmech.2020.113046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/20/2020] [Accepted: 11/22/2020] [Indexed: 12/11/2022]
Abstract
The tumour-associated, cell membrane-bound isoforms IX and XII of human carbonic anhydrase (CA, EC 4.2.1.1) are overexpressed in cancer cells contributing to the hypoxic tumour pH/metabolism regulating machinery and as thus, can serve as markers of malignant neoplastic tissue. Inhibitors of CAs can be employed both for the treatment of hypoxic tumours and in the design of radiotracers for positron emission tomography and imaging of such cancers. The present review provides a comprehensive summary of the progress achieved to-date in the field of developing PET-tracers based on monoclonal antibodies, biomolecules, and small-molecule ligands of CA IX and XII.
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83
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Dar’in D, Krasavin M, Chupakhin E, Gecht M, Ivanov A, Kantin G. (E)-3-Arylidene-4-diazopyrrolidine-2,5-diones: Preparation and Use in RhII-Catalyzed X–H Insertion Reactions towards Novel, Medicinally Important Michael Acceptors. SYNTHESIS-STUTTGART 2020. [DOI: 10.1055/s-0040-1706556] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
AbstractThe use of readily available 1-aryl-3-arylidenepyrrolidine-2,5-diones in high yielding direct diazo-transfer reactions and subsequent involvement of the resulting diazo compounds in RhII-catalyzed O–H, S–H, and N–H insertion reactions delivered 4-substituted 1-aryl-3-arylidenepyrrolidine-2,5-diones of defined regiochemistry and geometrical configuration. These products are intended to be studied as Michael acceptors capable of inhibiting thioredoxin reductase, a promising cancer target.
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84
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Krasavin M, Sharonova T, Sharoyko V, Zhukovsky D, Kalinin S, Žalubovskis R, Tennikova T, Supuran CT. Combining carbonic anhydrase and thioredoxin reductase inhibitory motifs within a single molecule dramatically increases its cytotoxicity. J Enzyme Inhib Med Chem 2020; 35:665-671. [PMID: 32131646 PMCID: PMC7067156 DOI: 10.1080/14756366.2020.1734800] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A hypothesis that simultaneous targeting cancer-related carbonic anhydrase hCA IX and hCA XII isoforms (whose overexpression is a cancer cell’s defence mechanism against hypoxia) along with thioredoxin reductase (overexpressed in cancers as a defence against oxidative stress) may lead to synergistic antiproliferative effects was confirmed by testing combinations of the two inhibitor classes against pancreatic cancer cells (PANC-1). Combining both pharmacophoric motifs within one molecule led to a sharp increase of cytotoxicity. This preliminary observation sets the ground for a fundamentally new approach to anticancer agent design.
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85
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Jovanović M, Dragoj M, Zhukovsky D, Dar'in D, Krasavin M, Pešić M, Podolski-Renić A. Novel TrxR1 Inhibitors Show Potential for Glioma Treatment by Suppressing the Invasion and Sensitizing Glioma Cells to Chemotherapy. Front Mol Biosci 2020; 7:586146. [PMID: 33134322 PMCID: PMC7573255 DOI: 10.3389/fmolb.2020.586146] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/10/2020] [Indexed: 01/13/2023] Open
Abstract
Currently, available glioblastoma (GBM) treatment remains ineffective, with relapse after initial response and low survival rate of GBM patients. The reasons behind limited capacities for GBM treatment are high tumor heterogeneity, invasiveness, and occurrence of drug resistance. Therefore, developing novel therapeutic strategies is of utmost importance. Thioredoxin reductase (TrxR) is a novel, promising target due to its overexpression in many cancer types and important role in cancer progression. Previous research on Ugi-type Michael acceptors–inhibitors of TrxR showed desirable anticancer properties, with significant selectivity toward cancer cells. Herein, two TrxR inhibitors, 5 and 6, underwent in-depth study on multidrug-resistant (MDR) glioma cell lines. Besides the antioxidative effects, 5 and 6 induced cell death, decreased cell proliferation, and suppressed invasion and migration of glioma cells. Both compounds showed a synergistic effect in combination with temozolomide (TMZ), a first-line chemotherapeutic for GBM treatment. Moreover, 5 and 6 affected activity of P-glycoprotein extrusion pump that could be found in cancer cells and in the blood–brain barrier (BBB), thus showing potential for suppressing MDR phenotype in cancer cells and evading BBB. In conclusion, investigated TrxR inhibitors are effective anticancer compounds, acting through inhibition of the thioredoxin system and perturbation of antioxidative defense systems of glioma cells. They are suitable for combining with other chemotherapeutics, able to surpass the BBB and overcome MDR. Thus, our findings suggest further exploration of Ugi-type Michael acceptors–TrxR inhibitors’ potential as an adjuvant therapy for GBM treatment.
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86
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Chuprun S, Dar’in D, Rogacheva E, Kraeva L, Levin O, Manicheva O, Dogonadze M, Vinogradova T, Bakulina O, Krasavin M. Mutually Isomeric 2- and 4-(3-nitro-1,2,4-triazol-1-yl)pyrimidines Inspired by an Antimycobacterial Screening Hit: Synthesis and Biological Activity against the ESKAPE Panel of Pathogens. Antibiotics (Basel) 2020; 9:antibiotics9100666. [PMID: 33019787 PMCID: PMC7601023 DOI: 10.3390/antibiotics9100666] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 09/24/2020] [Accepted: 09/30/2020] [Indexed: 11/16/2022] Open
Abstract
Starting from the structure of antimycobacterial screening hit OTB-021 which was devoid of activity against ESKAPE pathogens, we designed, synthesized and tested two mutually isomeric series of novel simplified analogs, 2- and 4-(3-nitro-1,2,4-triazol-1-yl)pyrimidines, bearing various amino side chains. These compounds demonstrated a reverse bioactivity profile being inactive against M. tuberculosis while inhibiting the growth of all ESKAPE pathogens (with variable potency patterns) except for Gram-negative P. aeruginosa. Reduction potentials (E1/2, V) measured for selected compounds by cyclic voltammetry were tightly grouped in the -1.3--1.1 V range for a reversible single-electron reduction. No apparent correlation between the E1/2 values and the ESKAPE minimum inhibitory concentrations was established, suggesting possible significance of other factors, besides the compounds' reduction potential, which determine the observed antibacterial activity. Generally, more negative E1/2 values were displayed by 2-(3-nitro-1,2,4-triazol-1-yl)pyrimidines, which is in line with the frequently observed activity loss on moving the 3-nitro-1,2,4-triazol-1-yl moiety from position 4 to position 2 of the pyrimidine nucleus.
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87
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Safrygin A, Dar'in D, Bakulina O, Krasavin M. Synthesis of spirocyclic tetrahydroisoquinolines (spiroTHIQs) via the Castagnoli-Cushman reaction. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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88
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Grintsevich S, Sapegin A, Reutskaya E, Peintner S, Erdélyi M, Krasavin M. Front Cover: An Alternative Approach to the Hydrated Imidazoline Ring Expansion (HIRE) of Diarene‐Fused [1.4]Oxazepines (Eur. J. Org. Chem. 35/2020). European J Org Chem 2020. [DOI: 10.1002/ejoc.202001186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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89
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Golubev P, Guranova N, Krasavin M. 1,3,5-Triazinanes as Formaldimine Surrogates in the Ugi Reaction. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000569] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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90
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Krasavin M, Safrygin A, Bakulina O, Dar’in D. Three-Component Reaction of Homophthalic Anhydride with Carbonyl Compounds and Ammonium Acetate: New Developments. SYNTHESIS-STUTTGART 2020. [DOI: 10.1055/s-0040-1708017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The earlier described reaction of homophthalic anhydrides with aromatic ketones and ammonium acetate was tested for cyclic ketones (yielding spirocyclic motifs) and aliphatic aldehydes. In contrast to previous findings, the reaction was found to require no catalyst at all and to be applicable, in the non-catalyzed format, to these new carbonyl substrates as well as aromatic ketones. The reaction typically proceeds with high diastereoselectivity; if not, the initial diastereomeric mixture can be quantitatively equilibrated into a single, trans-diastereomer on treatment with aqueous base.
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91
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Burianova V, Dar'in D, Krasavin M. Direct conversion of diazo compounds to fluoro derivatives. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152255] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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92
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Krasavin M, Synofzik J, Bakulina O, Dar’in D, Kantin G. Dialkyl Diazomalonates in Transition-Metal-Free, Thermally Promoted, Diastereoselective Wolff β-Lactam Synthesis. Synlett 2020. [DOI: 10.1055/s-0040-1707811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Metal-free, thermally promoted synthesis of 3-alkoxy-3-alkoxycarbonyl-2-azetidinones via the Wolff-Staudinger β-lactam synthesis using dialkyl diazomalonates is described. The reaction appears fairly general and delivers only one diastereomer.
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93
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Bubyrev A, Dar'in D, Kantin G, Krasavin M. Cover Feature: Synthetic Studies towards CH‐Diazomethane Sulfonamides: a Novel Type of Diazo Reagents (Eur. J. Org. Chem. 27/2020). European J Org Chem 2020. [DOI: 10.1002/ejoc.202000948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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94
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Krasavin M, Synofzik J, Bakulina O, Balabas O, Dar’in D. Catalyst-Free Synthesis of Diastereomerically Pure 3-Sulfonylazetidin-2-ones via Microwave-Assisted Tandem Wolff Rearrangement–Staudinger Cycloaddition. SYNTHESIS-STUTTGART 2020. [DOI: 10.1055/s-0040-1707193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
A wide range of α-diazo-β-ketosulfones have been applied to thermally promoted tandem Wolff rearrangement – Staudinger [2+2] cycloaddition with imines to give polysubstituted β-lactam sulfones. Diastereomerically pure syn-diastereomers were obtained in good yields and the relative stereochemistry was confirmed by single-crystal X-ray crystallography. These findings significantly expand the scope of this transformation, in contrast to substantial limitations reported previously. Moreover, this methodology enables flexible exploration of new substitution patterns around the privileged β-lactam core for drug design and optimization.
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95
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Dar’in D, Krasavin M, Inyutina A, Chupakhin E. A Novel Approach to Substituted α-Carbamoyl Phosphonates: Useful Reagents for the Horner–Wadsworth–Emmons Olefination. Synlett 2020. [DOI: 10.1055/s-0040-1707200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
α-Carbamoyl phosphonates are useful reagents for the Horner–Wadsworth–Emmons olefination of aldehydes en route to medicinally relevant polysubstituted acrylamides. A new synthetic approach to these reagents has been developed. The methodology relies on the microwave-promoted Wolff rearrangement of α-acyl-α-diazophosphonates with trapping of the ketene intermediate in situ with various amines.
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96
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Grintsevich S, Sapegin A, Reutskaya E, Peintner S, Erdélyi M, Krasavin M. An Alternative Approach to the Hydrated Imidazoline Ring Expansion (HIRE) of Diarene‐Fused [1.4]Oxazepines. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000789] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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97
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Dmitriev V, Vedekhina T, Sapegin A, Krasavin M. Convenient Assembly of Privileged (Hetero)Arene‐Fused Benzo[1.4]oxazepines via Two Tandem S
N
Ar Events. Part 3 – (Hetero)arene‐Fused benzo[
f
]imidazo[1,2‐
d
][1,4]oxazepines. ChemistrySelect 2020. [DOI: 10.1002/slct.202002033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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98
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Levashova E, Bakulina O, Dar'in D, Bubyrev A, Chuprun S, Krasavin M. From Rare Reagents to Rare Products: Regiospecific Silver‐Catalyzed [3+2] Cycloaddition of Aryl‐, Alkyl‐ and Aminosulfonyl Diazomethanes with Arenediazonium Tosylates. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000619] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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99
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Bakholdina A, Lukin A, Bakulina O, Guranova N, Krasavin M. Dual use of propargylamine building blocks in the construction of polyheterocyclic scaffolds. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.151970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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100
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Krasavin M, Eremeyeva M, Zhukovsky D, Dar’in D. The Use of α-Diazo-γ-butyrolactams in the Büchner–Curtius–Schlotterbeck Reaction of Cyclic Ketones Opens New Entry to Spirocyclic Pyrrolidones. Synlett 2020. [DOI: 10.1055/s-0040-1708011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The only cyclic α-diazocarbonyl compound employed in the Büchner–Curtius–Schlotterbeck ring expansion of cyclic ketones to date was α-diazo-γ-butyrolactone. Encouraged by the recent success using α-diazo acetamides in related Tiffeneau–Demjanov type ring expansions, we extended this approach to various α-diazo-γ-butyrolactams, which produced, under BF3·OEt2-promoted conditions, spirocyclic seven-membered ketones. These findings substantially enhance the possibilities offered by cyclic α-diazocarbonyl compounds in constructing privileged spirocyclic scaffolds for drug design.
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