Papers - Sugai, Takeshi

Dual delivery of carbon monoxide and doxorubicin using haemoglobin-albumin cluster: proof of concept for well-tolerated cancer therapy

Ito C., Taguchi K., Yamada T., Hanaya K., Enoki Y., Sugai T., Komatsu T., Matsumoto K.

Journal of Materials Chemistry B 12 ( 23 ) 5600 - 5608 2024.05

ISSN  2050750X

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A serious concern of doxorubicin (DOX) therapy is that it causes severe adverse effects, particularly cardiotoxicity. Carbon monoxide (CO) possesses powerful cytoprotective effects against drug-induced organ injury and is expected to ameliorate DOX-induced cardiotoxicity. In this study, a dual carrier of DOX and CO (CO-HemoAct-DOX) was fabricated based on a haemoglobin-albumin cluster (HemoAct), which is a protein cluster with a haemoglobin core structure wrapped by serum albumin. CO-HemoAct-DOX was synthesised by binding CO to a haemoglobin core and covalently conjugating (6-maleimidocaproyl)hydrazone derivative of DOX to an albumin shell. The average DOX/cluster ratio was about 2.6. In the in vitro cytotoxicity assay against cancer cells, the anti-tumour activity of CO-HemoAct-DOX was 10-fold lower than that of DOX in a 2D-cultured model, whereas CO-HemoAct-DOX suppressed the growth of tumour spheroids to the same extent as DOX in the 3D-cultured model. In colon-26 tumour-bearing mice, CO-HemoAct-DOX achieved DOX delivery to the tumour site and alleviated tumour growth more effectively than DOX. Furthermore, CO-HemoAct attenuated DOX-induced cardiomyocyte atrophy in H9c2 cells and elevated the levels of cardiac biomarkers in mice exposed to DOX. These results suggest that the dual delivery of CO and DOX using HemoAct is a promising strategy as an anti-tumour agent to realise well-tolerated cancer therapy with minimal cardiotoxicity.

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Synthesis and luminescence properties of substituted benzils

Yasui M., Fujihara T., Ohtsu H., Wada Y., Shimada T., Zhu Y., Kawano M., Hanaya K., Sugai T., Higashibayashi S.

Communications Chemistry 6 ( 1 )  2023.12

Research paper (scientific journal), Accepted

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Photophysical properties of benzil (1,2-diphenylethane-1,2-dione) and its derivatives in the crystal state have recently attracted much attention. However, the study of substituted benzils has mostly been limited to para-substituted derivatives, which did not induce a significant effect on the emission wavelength compared to pristine benzil. The effects of ortho- and meta-substituents on the photophysical properties in the crystal state have not been investigated so far. Our recently developed organocatalytic pinacol coupling of substituted benzaldehydes allowed us to prepare various ortho-, meta-, and para-substituted benzil derivatives and to investigate their luminescence properties. Ortho- and meta-substituents affected the electronic states of benzils in the crystal state, resulting in differences in their luminescence properties. The luminescence wavelength and type, i.e., phosphorescence or fluorescence, were altered by these substituents. Fast self-recovering phosphorescence-to-phosphorescence mechanochromism by the para-CF3 substituent at room temperature was also discovered.

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Unified short syntheses of oxygenated tricyclic aromatic diterpenes by radical cyclization with a photoredox catalyst

Hashimoto R., Hanaya K., Sugai T., Higashibayashi S.

Communications Chemistry 6 ( 1 )  2023.12

Research paper (scientific journal), Accepted

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The biomimetic two-phase strategy employing polyene cyclization and subsequent oxidation/substitution is an effective approach for divergent syntheses of [6-6-6]-tricyclic diterpenes. However, this strategy requires lengthy sequences for syntheses of oxygenated tricyclic aromatic abietane/podocarpane diterpenes owing to the many linear oxidation/substitution steps after cyclization. Here, we present a new synthetic route based on a convergent reverse two-phase strategy employing a reverse radical cyclization approach, which enabled the unified short syntheses of four aromatic abietane/podocarpane diterpenes and the divergent short syntheses of other related diterpenes. Oxygenated and substituted precursors for cyclization were convergently prepared through Friedel-Crafts acylation and rhodium-catalyzed site-selective iodination. Radical redox cyclization using an iridium photoredox catalyst involving neophyl rearrangement furnished the thermodynamically favored 6-membered ring preferentially. (±)-5,6-Dehydrosugiol, salvinolone, crossogumerin A, and Δ5-nimbidiol were synthesized in only 8 steps. An oxygenated cyclized intermediate was also useful for divergent derivatization to sugiol, ferruginol, saprorthoquinone, cryptomeriololide, and salvinolone.

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Selective modification of tryptophan in polypeptides via C-N coupling with azoles using in situ-generated iodine-based oxidants in aqueous media

Watanabe S., Wada Y., Kawano M., Higashibayashi S., Sugai T., Hanaya K.

Chemical Communications 59 ( 87 ) 13026 - 13029 2023.10

Research paper (scientific journal), Accepted,  ISSN  13597345

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This study demonstrates the C-N coupling of tryptophan with azoles, promoted by an in situ-generated iodine-based oxidant. The protocol was successfully applied to the selective modification of tryptophan in nonprotected polypeptide bearing oxidatively sensitive residues in acidic aqueous media. The present method allows the attachment of reactive handles to polypeptides and the peptide stapling.

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Inversion of Diaza[5]Helicenes Through an N−N Bond Breaking Pathway

Kobayashi T., Ishiwari F., Fukushima T., Nojima Y., Hasegawa M., Mazaki Y., Hanaya K., Sugai T., Higashibayashi S.

Chemistry - A European Journal 29 ( 43 )  2023.08

Research paper (scientific journal), Accepted,  ISSN  09476539

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1,1’,10,10’-Biphenothiazine and its S,S,S’,S’-tetroxide are diaza[5]helicenes with N−N linkages. Kinetic experiments on racemization together with DFT calculations revealed that they undergo inversion through the N−N bond breaking pathway rather than the general conformational pathway. In these diaza[5]helicenes with this inversion mechanism, the reduction of electronic repulsion in the N−N bond by modification of S to SO2 at the outer position of the helix led to a significantly higher inversion barrier, 35.3 kcal/mol, compared to [5]helicene. 1,1’,10,10’-Biphenothiazine S,S,S’,S’-tetroxide was highly resistant to acid-mediated N−N bond breaking and racemization under acidic conditions.

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Intramolecular cyclization of m-homoprenylphenols through oxidative nucleophilic aromatic substitution

Deguchi H., Hanaya K., Sugai T., Higashibayashi S.

Chemical Communications 59 ( 6 ) 748 - 751 2022.12

Research paper (scientific journal), Accepted,  ISSN  13597345

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We developed an intramolecular cyclization of m-homoprenylphenols and related m-prenylphenols to bicyclic skeletons by hypervalent iodine reagents through an oxidative nucleophilic aromatic substitution using the prenyl group as a carbon nucleophile. The reaction was applicable for the syntheses of 5/6-, 6/6-, and 7/6-fused ring systems.

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Copper-Catalyzed Stereoselective Borylation and Palladium-Catalyzed Stereospecific Cross-Coupling to Give Aryl C-Glycosides

Kurahayashi K., Hanaya K., Sugai T., Hirai G., Higashibayashi S.

Chemistry - A European Journal 29 ( 6 )  2022.12

Research paper (scientific journal), Accepted

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Metabolically stable C-glycosides are an essential family of compounds in bioactive natural products, therapeutic agents, and biological probes. For their application, development of synthetic methods by connecting glycosides and aglycons with strict stereocontrol at the anomeric carbon, as well as with high functional-group compatibility and environmental compatibility is a pivotal issue. Although Suzuki–Miyaura-type C(sp3)−C(sp2) cross-coupling using glycosyl boronates is a potential candidate for the construction of C-glycosides, neither the cross-coupling itself nor the facile synthesis of the coupling precursor, glycosyl boronates, have been achieved to date. Herein, it was succeeded to develop a copper-catalyzed stereoselective one-step borylation of glycosyl bromides to glycosyl boronates and palladium-catalyzed stereospecific cross-coupling of β-glycosyl borates with aryl bromides to give aryl β-C-glycosides, in which the β-configuration of the anomeric carbon of the glycosyl trifluoroborates is stereoretentively transferred to that of the resulting aryl C-glycosides.

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Chemoselectivity-independent Cu-mediated coupling to construct the hydroquinoline skeleton of symbioimine

Fujita R., Hanaya K., Sugai T., Higashibayashi S.

Scientific Reports 11 ( 1 )  2022.12

Research paper (scientific journal), Accepted

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Construction of the hydroquinoline skeleton of symbioimine by Cu-mediated N-alkenylation or O-alkenylation of an allyl aminoalcohol, in which either chemoselectivity could lead to the target compound, was investigated. O-alkenylation followed by Claisen rearrangement was favored with high selectivity under a ligand-free condition. Subsequent intramolecular condensation furnished the hydroquinoline skeleton of symbioimine.

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Transition-metal-free β-selective C-glycosylation of β-glycosyl boronate via stereoretentive 1,2-migration

Hiroki Yasutomi, Daiki Takeda, Makoto Yoritate, Shuhei Higashibayashi, Takeshi Sugai, Go Hirai

Synlett 34   347 - 352 2022.11

Research paper (scientific journal), Accepted

Single-Step N-Terminal Modification of Proteins via a Bio-Inspired Copper(II)-Mediated Aldol Reaction

Hanaya K., Yamoto K., Taguchi K., Matsumoto K., Higashibayashi S., Sugai T.

Chemistry - A European Journal 28 ( 47 ) 347 - 352 2022.08

Research paper (scientific journal), Last author, Accepted

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The chemical modification of proteins is an effective technique for manipulating the properties and functions of proteins, and for creating protein-based materials. The N-terminus is a promising target for single-site modification that provides modified proteins with uniform structures and properties. In this paper, a copper(II)-mediated aldol reaction with 2-pyridinecarboxaldehyde (2-PC) derivatives is proposed as an operationally simple method to selectively modify the N-terminus of peptides and proteins at room temperature and physiological pH. The copper(II) ion activates the N-terminal amino acids by complexation with an imine of the N-terminal amino acid and 2-PCs, realizing the selective formation of the nucleophilic intermediate at the N-terminus. This results in a stable carbon-carbon bond between the 2-PCs and the α-carbon of various N-terminal amino acids. The reaction is applied to four different proteins, including biopharmaceuticals such as filgrastim and trastuzumab. The modified trastuzumab retains the human epidermal growth factor receptor 2 recognition activity.

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One-Step Synthesis of Acylborons from Acyl Chlorides through Copper-Catalyzed Borylation with Polystyrene-Supported PPh<inf>3</inf>Ligand

Nakahara M., Kurahayashi K., Hanaya K., Sugai T., Higashibayashi S.

Organic Letters 24 ( 30 ) 5596 - 5601 2022.08

Research paper (scientific journal), Accepted

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We developed a one-step synthesis of acylborons from both readily available acyl chlorides and bis(pinacolato)diboron through copper(I)-catalyzed borylation. Under the reaction conditions using tBuOLi, polystyrene-supported triphenylphosphine as a copper ligand was found to promote the borylation of acyl chlorides while suppressing alcoholysis. This method enables the facile synthesis of potassium acyltrifluoroborates.

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1,2-Rearrangement from o-Quinols to Multisubstituted Catechols via Retro Diels-Alder Reaction of o-Quinol Dimers

Hashimoto R., Hanaya K., Sugai T., Higashibayashi S.

Bulletin of the Chemical Society of Japan 95 ( 4 ) 663 - 672 2022.04

Research paper (scientific journal), Accepted

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The 1,2-rearrangement of o-quinols has been a long-standing unsolved problem since 1958. Although the rearrangement is expected to be useful for syntheses of catechol derivatives, it is hampered by many competing reactions and has not been developed as a useful methodology. Here, we succeeded in settling this problem by a first systematic thorough investigation, establishing the 1,2-rearrangement as a cascade reaction with a retro Diels-Alder reaction from o-quinol dimers. This is a useful strategy for syntheses of substituted catechols used as synthetic building blocks for bioactive compounds and material molecules. o-Quinol dimers were synthesized by improved oxidative hydroxylation of substituted phenols followed by spontaneous Diels-Alder reaction. The dimers then underwent the retro Diels-Alder reaction to regenerate the o-quinols followed by 1,2-rearrangement under neutral heating conditions at an appropriate temperature depending on the migratory substituent, furnishing substituted catechols in good yields. The competing reactions such as an elimination of a substituent or α-ketol rearrangement were minimized by controlling the reaction temperature.

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Synthesis of 1H-2-Benzopyran-5,8-dione Skeleton through a Cascade Reaction between Benzoquinone and β-Ketoester

Nakahara M., Ohtsu H., Kawano M., Hanaya K., Sugai T., Higashibayashi S.

Chemistry Letters 51 ( 4 ) 356 - 359 2022.04

Research paper (scientific journal), Accepted

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The 1H-2-benzopyran-5,8-dione structure was synthesized by a cascade reaction through Michael addition, elimination of HBr, and O-alkylation between a dibromobenzoquinone derivative and β-ketoesters under basic conditions. The reaction using potassium carbonate and 18-crown-6 in THF was the best condition, giving 1H-2-benzopyran-5,8-dione derivatives in good yields. The UV-vis absorption spectrum and cyclic voltammogram of the synthesized 1H-2-benzopyran-5,8-dione derivative were measured, clarifying the photophysical and redox properties.

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Isorhamnetin promotes 53BP1 recruitment through the enhancement of ATM phosphorylation and protects mice from radiation gastrointestinal syndrome

Nishiyama Y., Morita A., Tatsuta S., Kanamaru M., Sakaue M., Ueda K., Shono M., Fujita R., Wang B., Hosoi Y., Aoki S., Sugai T.

Genes (Genes)  12 ( 10 )  2021.10

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Flavonoids are a subclass of polyphenols which are attractive, due to possessing various physiological activities, including a radioprotective effect. Tumor suppressor p53 is a primary reg-ulator in the radiation response and is involved in the pathogenesis of radiation injuries. In this study, we revealed that isorhamnetin inhibited radiation cell death, and investigated its action mechanism focusing on DNA damage response. Although isorhamnetin moderated p53 activity, it promoted phosphorylation of ataxia telangiectasia mutated (ATM) and enhanced 53BP1 recruitment in irradiated cells. The radioprotective effect of isorhamnetin was not observed in the presence of ATM inhibitor, indicating that its protective effect was dependent on ATM. Furthermore, iso-rhamnetin-treated mice survived gastrointestinal death caused by a lethal dose of abdominal irra-diation. These findings suggested that isorhamnetin enhances the ATM-dependent DNA repair pro-cess, which is presumably associated with the suppressive effect against GI syndrome.

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Metal-free thermal organocatalytic pinacol coupling of arylaldehydes using an isonicotinate catalyst with bis(pinacolato)diboron

Yasui M., Hanaya K., Suugai T., Higashibayashi S.

RSC Advanced (RSC Advances)  2021 ( 11 ) 24652 - 24655 2021.08

Accepted

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The metal-free thermal organocatalytic pinacol coupling of arylaldehydes has been developed. The intermolecular coupling of arylaldehydes catalyzed by t-butyl isonicotinate with bis(pinacolato)diboron as the co-reducing agent afforded 1,2-diphenylethane-1,2-diols. This reaction was also applicable to the intramolecular coupling of 1,10-biphenyl-2,20-dicarbaldehydes to afford 9,10-dihydrophenanthrene-9,10-diols. Various functional groups were tolerated under this coupling condition.

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A Concise Total Synthesis of Dehydroantofine and Its Antimalarial Activity against Chloroquine-Resistant Plasmodium falciparum

Yamasaki N., Iwasaki I., Sakumi K., Hokari R., Ishiyama A., Iwatsuki M., Nakahara M., Higashibayashi S., Sugai T., Imagawa H., Kubo M., Fukuyama Y., Ōmura S., Yamamoto H.

Chemistry - A European Journal (Chemistry - A European Journal)  27 ( 17 ) 5555 - 5563 2021.03

Accepted,  ISSN  09476539

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The total synthesis of dehydroantofine was achieved by employing a novel, regioselective, azahetero Diels–Alder reaction of easily accessible 3,5-dichloro-2H-1,4-oxazin-2-one with 14 a as a key step. Furthermore, it is demonstrated that dehydroantofine is a promising candidate as a new antimalarial agent in a biological assay with chloroquine-resistant Plasmodium falciparum.

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Chemo-enzymatic Semisynthesis of Caffeic Acid β-Phenethyl Ester, an Antioxidative Component in Propolis, from Raw Coffee Beans Extract

R. Hashimoto, H. Iai, R. Fujita, K. Hanaya, S. Higashibayashi, H. Inoue, T. Sugai

Bioscience, Biotechnology and Biochemistry 85   476 - 480 2021.03

Research paper (scientific journal), Joint Work, Accepted,  ISSN  09168451

Nickel(II)-Mediated C−S Cross-Coupling Between Thiols and ortho-Substituted Arylboronic Acid

Hanaya K., Ohtsu H., Kawano M., Higashibayashi S., Sugai T.

Asian Journal of Organic Chemistry (Asian Journal of Organic Chemistry)  10 ( 3 ) 582 - 587 2021.03

Accepted,  ISSN  21935807

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Herein, we report a C−S cross-coupling reaction between alkyl thiols or aryl thiols and ortho-substituted arylboronic acids that proceeds in the presence of an inexpensive and ligand-free NiCl2 ⋅ 6H2O salt and N-methylmorpholine, a weak base, at 25 °C in air. The presence of coordinating and electron-withdrawing groups at the ortho-position of the arylboronic acids played a crucial role in determining the efficiency of the reaction. X-ray crystallographic analysis revealed that the [NiCl2(DMF)2(H2O)2] complex was formed in-situ. The complex is an excellent precursor of the active nickel species. The reaction offers an extremely mild and operationally convenient method to access a wide variety of alkyl aryl sulfides and diaryl sulfides without using expensive transition metals, such as palladium, gold, and rhodium, and specialized and expensive ligands.

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Analysis of Interconversion between Atropisomers of Chiral Substituted 9,9’-Bicarbazole

T. Kobayashi, F. Ishiwari, T. Fukushima, K. Hanaya, T. Sugai, S. Hibashibayashi

Eur. J. Org. Chem.    449 - 451 2021.02

Research paper (scientific journal), Joint Work, Accepted,  ISSN  09168451

Selective capture and noninvasive release of cells using a thermoresponsive polymer brush with affinity peptides

K. Nagase, M. Shimura, R. Shimane, K. Hanaya, S. Yamada, A. Mizutani-Akimoto, T. Sugai, H. Kanazawa

Biomater. Sci. (Biomaterials Science)  9 ( 3 ) 663 - 674 2021.01

Research paper (scientific journal), Joint Work, Accepted,  ISSN  20474830

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Tissue engineering and cell transplantation therapy have become promising therapies for intractable diseases. These approaches require cell separation technology without cell modification. Accordingly, in this study, we developed a novel cell separation method using a thermoresponsive block copolymer brush with an affinity peptide. A block copolymer brush with bottom poly(2-hydroxyethyl methacrylate [HEMA]-co-propargyl acrylate) and top poly(N-isopropylacrylamide-co-HEMA) segments was prepared through two steps of atom transfer radical polymerization. Then, cell affinity peptides were conjugated to the bottom segment of the copolymer brush through a click reaction. Using cRGD as a cell-Affinity peptide, enhancement of cell adhesion with rapid adhesion on the copolymer brush was observed at 37 °C, whereas the copolymer brush without cRGD did not exhibit cell adhesion. Temperature-modulated cell adhesion and detachment were performed with a relatively long upper segment because the affinity between peptides and cells was modulated by the swelling and shrinking of the upper thermoresponsive segment. Selective endothelial cell adhesion was performed at 37 °C using GGGREDV as an affinity peptide. Smooth muscle cells and fibroblasts did not adhere to the copolymer brush. Adhered human umbilical vein endothelial cells (HUVECs) were successfully recovered by reducing the temperature to 20 °C. Based on the properties of the copolymer brush, HUVECs could be purified using a mixture of cells simply by changing the temperature. These results demonstrated that the prepared copolymer brush with cell affinity peptides could be a useful cell separation tool because the cells could be separated with specificity and without cell modification using a simple procedure.

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