Co-reporter:Kenji Matsumoto, Shohei Tachikawa, Noriko Hashimoto, Rina Nakano, Masahiro Yoshida, and Mitsuru Shindo
The Journal of Organic Chemistry April 21, 2017 Volume 82(Issue 8) pp:4305-4305
Publication Date(Web):March 28, 2017
DOI:10.1021/acs.joc.7b00300
A novel, practical protocol for the aerobic direct C–H acetoxylation of arenes, employing a recyclable heterogeneous rhodium catalyst, is reported herein. The trifluoroacetoxylation of 2-amido-substituted anthracenes proceeded at the 9-position with exclusive regioselectivity. The oxidation of variously substituted anthracenes and other polycyclic aromatics with molecular oxygen as a terminal oxidant proceeded under mild conditions, providing products in good to excellent yields.
Co-reporter:Dr. Kenji Matsumoto; Masahiro Yoshida; Mitsuru Shindo
Angewandte Chemie International Edition 2016 Volume 55( Issue 17) pp:5272-5276
Publication Date(Web):
DOI:10.1002/anie.201600400
Abstract
The first heterogeneously catalyzed oxidative dehydrogenative cross-coupling of aryl amines is reported herein. 2-Naphthylamine analogues were reacted with various electron-rich arenes using a heterogeneous Rh/C catalyst under mild aerobic conditions, thus affording nonsymmetrical biaryl amines in excellent yields with high selectivities. This reaction provides a mild, operationally simple, and efficient approach for the synthesis of biaryls which are important to pharmaceutical and materials chemistry.
Co-reporter:Dr. Kenji Matsumoto; Masahiro Yoshida; Mitsuru Shindo
Angewandte Chemie 2016 Volume 128( Issue 17) pp:5358-5362
Publication Date(Web):
DOI:10.1002/ange.201600400
Abstract
The first heterogeneously catalyzed oxidative dehydrogenative cross-coupling of aryl amines is reported herein. 2-Naphthylamine analogues were reacted with various electron-rich arenes using a heterogeneous Rh/C catalyst under mild aerobic conditions, thus affording nonsymmetrical biaryl amines in excellent yields with high selectivities. This reaction provides a mild, operationally simple, and efficient approach for the synthesis of biaryls which are important to pharmaceutical and materials chemistry.
Co-reporter:Hiroshi Fukuda, Keisuke Nishikawa, Yukihiro Fukunaga, Katsuhiro Okuda, Kozue Kodama, Kenji Matsumoto, Arihiro Kano, Mitsuru Shindo
Tetrahedron 2016 Volume 72(Issue 41) pp:6492-6498
Publication Date(Web):13 October 2016
DOI:10.1016/j.tet.2016.08.060
We synthesized azo dye- and fluorescence-labeled cis-cinnamic acid analogues possessing inhibitory activity against lettuce root growth and a trans-isomer without bioactivity as a control probe. The radicles incubated with the azo dye-labeled analogue were stained red, with their tips especially deeply dyed. The fluorescent images of the radicles incubated with each of these molecular probes depicted that the root cap was fluorescence-stained. However, images of the control radicles prepared by staining with the trans-isomer fluorescent probe did not show emission at the root cap. These contrasts suggest specific localization of the cis-cinnamate analogue at the columella cells.
Co-reporter:Atsushi Yamamoto;Keisuke Hasui;Hiroshi Matsuo;Katsuhiro Okuda;Masato Abe;Kenji Matsumoto;Kazuki Harada;Yuya Yoshimura;Takenori Yamamoto;Kazuto Ohkura;Yasuo Shinohara
Chemical Biology & Drug Design 2015 Volume 86( Issue 5) pp:1304-1322
Publication Date(Web):
DOI:10.1111/cbdd.12594
Bongkrekic acid, isolated from Burkholderia cocovenenans, is known to specifically inhibit the mitochondrial ADP/ATP carrier. However, the manner of its interaction with the carrier remains elusive. In this study, we tested the inhibitory effects of 17 bongkrekic acid analogues, derived from the intermediates obtained during its total synthesis, on the mitochondrial ATP/ATP carrier. Rough screening of these chemicals, performed by measuring their inhibitory effects on the mitochondrial ATP synthesis, revealed that 4 of them, KH-1, KH-7, KH-16, and KH-17, had moderate inhibitory effects. Further characterization of the actions of these 4 analogues on mitochondrial function showed that KH-16 had moderate; KH-1 and KH-17, weak; and KH-7, negligible side effects of both permeabilization of the mitochondrial inner membrane and inhibition of the electron transport, indicating that only KH-7 had a specific inhibitory effect on the mitochondrial ADP/ATP carrier. Although the parental bongkrekic acid showed a strong pH dependency of its action, the inhibitory effect of KH-7 was almost insensitive to the pH of the reaction medium, indicating the importance of the 3 carboxyl groups of bongkrekic acid for its pH-dependent action. A direct inhibitory effect of KH-7 on the mitochondrial ADP/ATP carrier was also clearly demonstrated.
Co-reporter:Dr. Kenji Matsumoto;Masaki Suyama;Satoshi Fujita;Takuya Moriwaki;Yukiko Sato;Yoshifumi Aso;Satoshi Muroshita;Hiroshi Matsuo;Keishi Monda;Dr. Katsuhiro Okuda;Dr. Masato Abe;Dr. Hiroyuki Fukunaga; Arihiro Kano; Mitsuru Shindo
Chemistry - A European Journal 2015 Volume 21( Issue 32) pp:11590-11602
Publication Date(Web):
DOI:10.1002/chem.201501304
Abstract
Bongkrekic acid (BKA), isolated from the bacterium Burkholderia cocovenenans, is an inhibitor of adenine nucleotide translocator, which inhibits apoptosis, and is thus an important tool for the mechanistic investigation of apoptosis. An efficient total synthesis of BKA has been achieved by employing a three-component convergent strategy based on Kocienski–Julia olefination and Suzuki–Miyaura coupling. It is noteworthy that segment B has been prepared as a new doubly functionalized coupling partner, which contributes to shortening of the number of steps. Torquoselective olefination with an ynolate has also been applied for the efficient construction of an unsaturated ester. Furthermore, it is revealed that 1-methyl-2-azaadamantane N-oxyl is an excellent reagent for final oxidation to afford BKA in high yield. Based on the total synthesis, several BKA analogues were prepared for structure–activity relationship studies, which indicated that the carboxylic acid moieties were essential for the apoptosis inhibitory activity of BKA. More easily available BKA analogues with potent apoptosis inhibitory activity were also developed.
Co-reporter:Kenji Matsumoto, Kento Dougomori, Shohei Tachikawa, Takanori Ishii, and Mitsuru Shindo
Organic Letters 2014 Volume 16(Issue 18) pp:4754-4757
Publication Date(Web):September 9, 2014
DOI:10.1021/ol502197p
The first heterogeneous catalyzed oxidative coupling of aryl amines is reported. Aryl amines were dimerized at room temperature under air using a heterogeneous Rh/C catalyst in the presence of acids. By choosing a suitable acidic solvent, biaryl compounds and carbazoles were selectively prepared in good yields. This reaction is operationally simple and provides an efficient synthetic methodology for the preparation of biaryl diamines via oxidative C–H activation.
Co-reporter:Satoshi Umezu, Toshiya Yoshiiwa, Manabu Tokeshi, Mitsuru Shindo
Tetrahedron Letters 2014 Volume 55(Issue 10) pp:1822-1825
Publication Date(Web):5 March 2014
DOI:10.1016/j.tetlet.2014.01.147
A new method has been developed for the generation and subsequent reaction of ynolates in a micro flow reactor system. This new procedure allowed for ynolates to be prepared at 0 °C or ambient temperature within 1 min via a reductive lithiation reaction, whereas the corresponding batch processes generally require low temperature control and extended reaction times of up to 1 h. The resulting ynolates were applied to the olefination of carbonyl compounds, with the reactions reaching completion in a much shorter reaction time in the continuous flow reactor than the batch reactor. These results highlight the practical utility of the ynolate reaction, and represent the first reported example of the use of lithium naphthalenide in a flow microreactor, which would contribute to progress of the flash chemistry.
Co-reporter:Satoshi Umezu, Mitsuru Shindo
Tetrahedron Letters 2013 Volume 54(Issue 50) pp:6871-6873
Publication Date(Web):11 December 2013
DOI:10.1016/j.tetlet.2013.10.027
In the olefination reaction of ester carbonyl with ynolate, an α-hetero (N, O, S)-substituent on the substrates was found to markedly improve the yields of tetrasubstituted olefins, even though it was sterically hindered. The α-substituent effect may be due to several factors including the addition based on the polar Felkin–Anh model and restricted conformation of the initial adducts.
Co-reporter:Kenji Matsumoto, Kuniyoshi Koyachi, Mitsuru Shindo
Tetrahedron 2013 69(3) pp: 1043-1049
Publication Date(Web):
DOI:10.1016/j.tet.2012.11.077
Co-reporter:Keisuke Nishikawa, Hiroshi Fukuda, Masato Abe, Kazunari Nakanishi, Tomoya Taniguchi, Takashi Nomura, Chihiro Yamaguchi, Syuntaro Hiradate, Yoshiharu Fujii, Katsuhiro Okuda, Mitsuru Shindo
Phytochemistry 2013 Volume 96() pp:132-147
Publication Date(Web):December 2013
DOI:10.1016/j.phytochem.2013.08.013
•cis-Cinnamic acid analogues was synthesized having substituents on the aromatic ring, and their inhibitory activities on the elongation of lettuce roots were evaluated.•Para- and ortho-substitution decreased potency.•meta-Substituted cis-cinnamic acid analogues were more likely to be potent.•m-Iodo, m-methoxy and m-trifluoromethyl substituents induced higher potency.1-O-cis-Cinnamoyl-β-d-glucopyranose is one of the most potent allelochemicals that has been isolated from Spiraea thunbergii Sieb by Hiradate et al. It derives its strong inhibitory activity from cis-cinnamic acid (cis-CA), which is crucial for phytotoxicity. By preparing and assaying a series of cis-CA analogues, it was previously found that the key features of cis-CA for lettuce root growth inhibition are a phenyl ring, cis-configuration of the alkene moiety, and carboxylic acid. On the basis of a structure–activity relationship study, the substituent effects on the aromatic ring of cis-CA were examined by systematic synthesis and the lettuce root growth inhibition assay of a series of cis-CA analogues having substituents on the aromatic ring. While ortho- and para-substituted analogues exhibited low potency in most cases, meta-substitution was not critical for potency, and analogues having a hydrophobic and sterically small substituent were more likely to be potent. Finally, several cis-CA analogues were found to be more potent root growth inhibitors than cis-CA.
Co-reporter:Keisuke Nishikawa, Hiroshi Fukuda, Masato Abe, Kazunari Nakanishi, Yuta Tazawa, Chihiro Yamaguchi, Syuntaro Hiradate, Yoshiharu Fujii, Katsuhiro Okuda, Mitsuru Shindo
Phytochemistry 2013 Volume 96() pp:223-234
Publication Date(Web):December 2013
DOI:10.1016/j.phytochem.2013.10.001
•Conformationally constrained cis-cinnamic acid analogues were designed, in which the aromatic ring and the cis-olefin are connected by a carbon bridge.•Their inhibitory activities on elongation of lettuce roots was evaluated with inhibitory activities of five- and six-membered bridged compounds being enhanced.•The cis-analogue having a five-membered ring exhibited bioactivity ten times higher than cis-cinnamic acid.1-O-cis-Cinnamoyl-β-d-glucopyranose is known to be one of the most potent allelochemical candidates and was isolated from Spiraea thunbergii Sieb by Hiradate et al. (2004), who suggested that it derived its strong inhibitory activity from cis-cinnamic acid, which is crucial for phytotoxicity. In this study, key structural features and substituent effects of cis-cinnamic acid (cis-CA) on lettuce root growth inhibition was investigated. These structure–activity relationship studies indicated the importance of the spatial relationship of the aromatic ring and carboxylic acid moieties. In this context, conformationally constrained cis-CA analogues, in which the aromatic ring and cis-olefin were connected by a carbon bridge, were designed, synthesized, and evaluated as plant growth inhibitors. The results of the present study demonstrated that the inhibitory activities of the five-membered and six-membered bridged compounds were enhanced, up to 0.27 μM, and were ten times higher than cis-CA, while the potency of the other compounds was reduced.The conformationally constrained cis-cinnamic acid analogues, in which the aromatic ring and the cis-olefin are connected by a carbon bridge, were designed and synthesized in order to obtain useful information on the critical conformation needed for potency. Their inhibitory activities on the elongation of lettuce roots were also evaluated.
Co-reporter:Kenji Matsumoto
Advanced Synthesis & Catalysis 2012 Volume 354( Issue 4) pp:642-650
Publication Date(Web):
DOI:10.1002/adsc.201100627
Abstract
We have demonstrated that intramolecular hypercoordination of a carboxylic acid is a powerful activation strategy for the palladium-catalyzed cross-coupling reaction of trialkyl(vinyl)silanes and trialkyl(vinyl)germanes under fluoride-free conditions. Z-β-Trialkylsilyl- and Z-β-trialkylgermylacrylic acids, synthesized stereoselectively by olefination with ynolates, are highly stable and useful reagents for cross-coupling with a variety of aryl iodides to provide tetrasubstituted olefins possessing different carbon substituents in a stereocontrolled and diversity-oriented manner. An application to a stereoselective synthesis of (Z)-tamoxifen is also reported.
Co-reporter:Katsuhiro Okuda, Keisuke Hasui, Masato Abe, Kenji Matsumoto, and Mitsuru Shindo
Chemical Research in Toxicology 2012 Volume 25(Issue 10) pp:2253
Publication Date(Web):September 21, 2012
DOI:10.1021/tx300315h
Bongkrekic acid (BKA) is an inhibitor of adenine nucleotide translocase (ANT). Since inhibition of ANT is connected to the inhibition of cytochrome c release from mitochondria, which then results in the suppression of apoptosis, it has been used as a tool for the mechanistic investigation of apoptosis. BKA consists of a long carbon chain with two asymmetric centers, a nonconjugated olefin, two conjugated dienes, three methyl groups, a methoxyl group, and three carboxylic acids. This complicated chemical structure has caused difficulties in synthesis, supply, and biochemical mechanistic investigations. In this study, we designed and synthesized more simple tricarboxylic acids that were inspired by the molecular structure of BKA. Their cytotoxicity and apoptosis-preventing activity in HeLa cells and the effect on the mitochondrial inner membrane potential (ΔΨm) in HL-60 cells were then evaluated. All tested tricarboxylic acid derivatives including BKA showed little toxicity against HeLa cells. BKA and two of the synthesized derivatives significantly suppressed staurosporine (STS)-induced reductions in cell viability. Furthermore, STS-induced ΔΨm collapse was significantly restored by pretreatment with BKA and a tricarboxylic acid derivative. Other derivatives, in which one of three carboxylic acids was esterified, exhibited potent toxicity, especially a derivative bearing a carbon chain of the same length as that of BKA. In conclusion, we have developed a new lead compound as an apoptosis inhibitor bearing three carboxylic acids connected with the proper length of a long carbon chain.
Co-reporter:Masato Abe, Keisuke Nishikawa, Hiroshi Fukuda, Kazunari Nakanishi, Yuta Tazawa, Tomoya Taniguchi, So-young Park, Syuntaro Hiradate, Yoshiharu Fujii, Katsuhiro Okuda, Mitsuru Shindo
Phytochemistry 2012 Volume 84() pp:56-67
Publication Date(Web):December 2012
DOI:10.1016/j.phytochem.2012.08.001
1-O-cis-cinnamoyl-β-d-glucopyranose is one of the most potent allelochemicals isolated from Spiraea thunbergii Sieb. It is suggested that it derives its strong inhibitory activity from cis-cinnamic acid, which is crucial for phytotoxicity. It was synthesized to confirm its structure and bioactivity, and also a series of cis-cinnamic acid analogues were prepared to elucidate the key features of cis-cinnamic acid for lettuce root growth inhibition. The cis-cyclopropyl analogue showed potent inhibitory activity while the saturated and alkyne analogues proved to be inactive, demonstrating the importance of the cis-double bond. Moreover, the aromatic ring could not be replaced with a saturated ring. However, the 1,3-dienylcyclohexene analogue showed strong activity. These results suggest that the geometry of the C–C double bond between the carboxyl group and the aromatic ring is essential for potent inhibitory activity. In addition, using several light sources, the photostability of the cinnamic acid derivatives and the role of the C–C double bond were also investigated.Graphical abstractA series of cis-cinnamic acid analogues were synthesized to elucidate the key features for lettuce root growth inhibition. Inhibitory activities on elongation of lettuce roots were also evaluated.Highlights► cis-Cinnamic acid analogues were synthesized and their inhibitory activities evaluated on elongation of lettuce roots. ► The cis-configuration, the carboxylate and the planar ring are essential for this activity. ► The photostability of the cinnamic acid derivatives was investigated using several light sources.
Co-reporter:Kazumasa Matsuo, Keisuke Nishikawa, Mitsuru Shindo
Tetrahedron Letters 2011 Volume 52(Issue 43) pp:5688-5692
Publication Date(Web):26 October 2011
DOI:10.1016/j.tetlet.2011.08.104
The β-glycosyl esters of cis-cinnamic acid were synthesized directly using Hannesian’s unprotected glycosyl donor and the carboxylic acid in toluene. This protocol does not require protecting groups on the glycosyl donors, and high stereoselectivity was achieved. The first synthesis of a potent allelochemical, 1-O-cis-cinnamoyl-β-d-glucopyranose, is also described.
Co-reporter:Kazumasa Matsuo, Mitsuru Shindo
Tetrahedron 2011 67(5) pp: 971-975
Publication Date(Web):
DOI:10.1016/j.tet.2010.11.108
Co-reporter:Kazumasa Matsuo and Mitsuru Shindo
Organic Letters 2010 Volume 12(Issue 22) pp:5346-5349
Publication Date(Web):October 27, 2010
DOI:10.1021/ol102407k
The first catalytic acylation of alcohols with a thiol ester present in Wittig reagents under neutral conditions catalyzed by the Cu(II) salt through a push−pull mechanism is reported. Furthermore, a new methodology for the one-pot lactonization of acyloins by a copper catalyst is developed. The synthetic utility of this method for the synthesis of natural products is shown.
Co-reporter:Kentaro Yaji, Mitsuru Shindo
Tetrahedron Letters 2010 Volume 51(Issue 41) pp:5469-5472
Publication Date(Web):13 October 2010
DOI:10.1016/j.tetlet.2010.08.032
A synthetic study of the Stemona alkaloid stemonamide is described. The FeCl3-promoted fast Nazarov reaction of β-alkoxy divinyl ketones in the presence of t-BuOH afforded an α-methylene cyclopentenone, which was subsequently subjected to the Rh-catalyzed C–H amination to provide a fully appropriately substituted α-methylene cyclopentenone as the core skeleton of stemonamide.
Co-reporter:Kentaro Yaji, Mitsuru Shindo
Tetrahedron 2010 66(52) pp: 9808-9813
Publication Date(Web):
DOI:10.1016/j.tet.2010.10.084
Co-reporter:Kazumasa Matsuo, Keiko Ohtsuki, Takashi Yoshikawa, Kozo Shishido, Kaori Yokotani-Tomita, Mitsuru Shindo
Tetrahedron 2010 66(43) pp: 8407-8419
Publication Date(Web):
DOI:10.1016/j.tet.2010.08.061
Co-reporter:Takashi Yoshikawa and Mitsuru Shindo
Organic Letters 2009 Volume 11(Issue 23) pp:5378-5381
Publication Date(Web):November 4, 2009
DOI:10.1021/ol902086t
A highly torquoselective olefination of alkynoates to provide functionalized tetrasubstituted olefins, (E)-2-en-4-ynoic acids, is described. Addition of Brønsted acids dramatically switched the mode of the Ag(I)-catalyzed cyclization of the resulting enyne carboxylic acids to give either tetronic acids or 2-pyrones.
Co-reporter:Takashi Yoshikawa, Seiji Mori, Mitsuru Shindo
Tetrahedron 2009 65(43) pp: 8832-8838
Publication Date(Web):
DOI:10.1016/j.tet.2009.08.060
Co-reporter:Yukiko Sato, Yoshifumi Aso, Mitsuru Shindo
Tetrahedron Letters 2009 50(28) pp: 4164-4166
Publication Date(Web):
DOI:10.1016/j.tetlet.2009.04.129
Co-reporter:Mitsuru Shindo Dr.;Takashi Yoshikawa;Yasuaki Itou;Seiji Mori Dr.;Takeshi Nishii;Kozo Shishido Dr.
Chemistry - A European Journal 2006 Volume 12(Issue 2) pp:
Publication Date(Web):28 SEP 2005
DOI:10.1002/chem.200500574
Ynolates were found to react with α-alkoxy-, α-siloxy-, and α-aryloxyketones at room temperature to afford tetrasubstituted olefins with high Z selectivity. Since the geometrical selectivity was determined in the ring opening of the β-lactone enolate intermediates, the torquoselectivity was controlled by the ethereal oxygen atoms. From experimental and theoretical studies, the high Z selectivity is induced by orbital and steric interactions rather than by chelation. In a similar manner, α-dialkylamino ketones provided olefins with excellent Z selectivity. These products can be easily converted into multisubstituted butenolides and γ-butyrolactams in good yield.
Co-reporter:Shigenobu Fujimoto, Kenji Matsumoto, Takayuki Iwata, Mitsuru Shindo
Tetrahedron Letters (8 March 2017) Volume 58(Issue 10) pp:973-976
Publication Date(Web):8 March 2017
DOI:10.1016/j.tetlet.2017.01.075