HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Special Issue
Tohru Fukuyama's Special Issues, Vol. 99, No. 1, 2019
Published online: 14th September, 2018
■ Biomimetic Synthesis of Iheyamine A from Spirocyclic Oxindoles
Takumi Abe,* Syuhei Satake, and Koji Yamada*
*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan
Abstract
The biomimetic synthesis of azepinobisindole alkaloid iheyamine A from a spirocyclic oxindole via an oxidative rearrangement has been accomplished for the first time. Furthermore, an unprecedented method for constructing 2,1’-spirocyclic oxindoles from azepinobisindoles through an alternative oxidative rearrangement has been explored.
Published online: 5th November, 2018
■ Model Studies for the Total Synthesis of 11-Demethoxymyrtoidine and Myrtoidine
Amaan M. Kazerouni, Danny E. Mancheno, and Simon B. Blakey*
*Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA 30322, U.S.A.
Abstract
The malagasy alkaloids, isolated in the 1990s from Madagascan shrub Strychnos myrtoides, are a family of strychnos alkaloids whose members have been reported to potentiate chloroquine activity against resistant strains of Plasmodium falciparum malaria. 11-Demethoxymyrtoidine, myrtoidine, and malagashanine were identified as the major components of the shrub used by local populations to treat malaria. Herein we report our studies on model systems to construct the EF dihydropyran lactone moiety present in 11-demethoxymyrtoidine and myrtoidine, and initial studies toward the application of these strategies to the total synthesis of these alkaloids.
Published online: 24th October, 2018
■ Synthesis of Deuterated CycloDOPA with Hydrogen/Deuterium Exchange
Zetryana Puteri Tachrim, Shiori Nakagawa, Tadashi Nakamura, Fumina Ohashi, Natsumi Kurokawa, Haruna Wakasa, Yurika Tokoro, Yasuko Sakihama, Yasuyuki Hashidoko, Takeyuki Suzuki, and Makoto Hashimoto*
*Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
Abstract
CycloDOPA (5,6-dihydroxy-indoline-2-carboxylic acid, leukodopachrome) is one of metabolites derived from tyrosine, one of intermediate in melanin formation (mammalian) and betanidin main skeleton (betalain pigment in plant). Synthesis of deuterated cyclodopa via hydrogen/deuterium exchange by utilization of deuterium chloride (DCl) and deuterated triflic acid (TfOD) are reported. The novel fully deuterated aromatic cycloDOPA derivative can be formed depending on temperature and time of H/D exchange condition. The complete study of H/D exchange resulted in the selective deuterium between 4- and/or 7-position of aromatic hydrogen of cycloDOPA.
Published online: 16th October, 2018
■ Concise Synthesis of Kalasinamide, Marcanine A, and Geovanine, and Antiproliferative Activity Evaluation of Their Azaanthracenones
Takashi Nishiyama, Noriyuki Hatae,* Kyohko Chikaraishi, Keisuke Uchida, Chika Yokoyama, Satoshi Hibino, and Tominari Choshi*
*Graduate School of Pharmacy & Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan
Abstract
The total syntheses of kalasinamide (1), marcanine A (2), and geovanine (3) have been conducted by the formation of a fused pyridone-ring azaanthracenone core based on a Curtius rearrangement that is followed by the microwave-assisted thermal electrocyclization of an isocyanato-containing 2-azahexatriene system. The antiproliferative activities of these synthetic compounds against the HCT-116 colon tumor cells were evaluated by the MTT assay.
Published online: 15th October, 2018
■ Design and Synthesis of Cyclohexenyl-p-carborane Derivatives as a New Class of Progesterone Receptor Antagonists
Shinya Fujii, Naoki Yanagida, Shuichi Mori, Emiko Kawachi, and Hiroyuki Kagechika*
* Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
Abstract
We report here the synthesis and structure-activity relationships of a series of C-cyclohexenyl-p-carborane derivatives, which we designed as candidates for a novel class of progesterone receptor (PR) antagonists. Biological evaluation using T47D alkaline phosphatase assay revealed that several compounds exhibited potent PR-antagonistic activity. We also examined the selectivity of these compounds for PR over androgen receptor (AR). Among them, 11b functioned as a PR-selective antagonist, while other compounds, such as 13b, acted as PR/AR dual antagonists. Notably, docking simulations indicated that 11b and 13b bind in similar orientations to the ligand-binding site of PR, but in opposite orientations to that of AR. These findings could helpful for developing more selective ligands for PR.
Published online: 24th October, 2018
■ Heterospirocyclic 3-Amino-2H-azirines as Convenient Building Blocks in Peptide Synthesis
Christoph Strässler and Heinz Heimgartner*
*Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
Abstract
Heterospirocyclic 3-amino-2H-azirines with a tetrahydropyran (Thp), tetrahydrothiopyran (Tht), or N-protected piperidine (Pip) moiety are useful reagents for the preparation of peptides containing the corresponding six-membered heterocyclic 4-amino-4-carboxylic acid unit. In the present study, tripeptides of the type H-Asp-D-Ala-Xaa-OMe, where Xaa is the heterocyclic amino acid, were prepared according to the ‘azirine/oxazolone method’.
Published online: 21st November, 2018
■ A [3,3] Sigmatropic and Novel Ipso [3,3] Sigmatropic Rearrangement of 1-Hydroxyindole Chemistry
Yoshikazu Fukui, Tetsuya Kobayashi, Toshiya Kawasaki, Fumio Yamada, and Masanori Somei*
*Faculty of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
Abstract
Utilizing 1-aryloxyindole derivatives, we found a new type of [3,3] sigmatropic rearrangement reaction. We named it as ipso [3,3] sigmatropic rearrangement. The product structures are strictly determined by X-ray crystallographic analysis. Normal [3,3] sigmatropic rearrangement of 1-hydroxyindole derivative was found to be a useful synthetic method for 2H-pyrazino[1',2':1,5]pyrrolo[2,3-b]indole-1,4-dione derivative.
Published online: 22nd November, 2018
■ [Bis(trifluoroacetoxy)iodo]p-nitrobenzene and [Bis(trifluoroacetoxy)iodo]pentafluorobenzene as Lead Reagents for the Direct Ring Contraction of Lactams to Pyrrolidines
Samuel Aubert-Nicol, Nora Heinrich, Jean Lessard, and Claude Spino*
*Chemistry Department, University of Sherbrooke, 2500 Boul. Université, Sherbrooke, QC, J1K 2R1, Canada
Abstract
Two λ3‑iodanes, namely [bis(trifluoroacetoxy)iodo]p-nitrobenzene and [bis(trifluoroacetoxy)iodo]pentafluorobenzene, were used to effect the direct ring-contraction of lactams to pyrrolidines. Intense reaction optimization was necessary but only α,α-disubstituted lactams succumbed to our efforts thus far.
Published online: 13th December, 2018
■ Synthesis and Hybridization Properties of Oligonucleotides Including 2’-N-Alkoxycarbonyl-2’-amino-LNA Derivatives
Takashi Osawa, Shoko Yamashita, Ayumi Nakanishi, Yuta Ito, and Yoshiyuki Hari*
*Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Nishihama, Yamashiro-cho, Tokushima 770-8514, Japan
Abstract
2ʹ-Amino-LNA is an attractive material that helps in realizing the practical use of oligonucleotides because it can stabilize complexes with complementary strands and various substituents can be introduced on the 2ʹ-amino group. Here, 2ʹ-N-alkoxycarbonyl derivatives of 2ʹ-amino-LNA were newly designed, synthesized, and incorporated into oligonucleotides. The results of UV-melting analysis indicated that 2ʹ-N-alkoxycarbonyl-modified 2ʹ-amino-LNA could enhance the stability of the duplex formed with single-stranded RNA and the triplex formed with double-stranded DNA.
Published online: 26th December, 2018
■ Identification of Target Protein for Batzelladines as CD4
Jun Shimokawa* and Kazuo Nagasawa*
*Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
Abstract
Batzelladines are a family of polycyclic guanidine alkaloids. Among the congeners, batzelladines A-E were reported to inhibit the interaction of human immunodeficiency virus (HIV) gp120 protein with human CD4. Here, we designed a batzelladine photoaffinity probe bearing trifluoromethyl-3H-diazirine and biotin groups, and employed it to establish the identity of the target protein of batzelladines as CD4.
Published online: 9th November, 2018
■ Synthesis of Novel Resveratrol-Phthalide Hybrid Compounds and Evaluation of Their Inhibitory Activities of Nitric Oxide Production
Tetsutaro Kimachi,* Tokutaro Ogata, Misae Doe, Mariko Sakanaka, Arisa Nishiuchi, Mio Aomatsu, Manami Tanaka, Maki Shimizu, Natsuko Yoshioka, Kurumi Kubota, Yui Teraoka, Chikako Nakajima, and Satoru Takahashi*
*School of Pharmaceutical Sciences, Mukogawa Women's University, 11-68 Koushien Kyuban-Cho, Nishinomiya, Hyogo 663-8179, Japan
Abstract
Four types of novel resveratrol-phthalide hybrid compounds were designed and synthesized systematically by Suzuki-Miyaura cross-coupling reaction. These hybrid compounds were evaluated upon an inhibitory effect of the LPS-stimulated NO production in murine macrophage cell line, RAW264.7. As a result, two of them showed stronger inhibitory activity than the original resveratrol.
Published online: 14th December, 2018
■ First Total Synthesis of Palmarumycin C6 Based on Double Oxa-Michael Addition of 1,8-Dihydroxynaphthalene to 3-Bromo-1-indenone
Hirokazu Tsukamoto, Yumi Nomura, and Takayuki Doi*
*Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aza-aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
Abstract
Synthetic studies on palmarumycin C6 with a naphthyl acetal at the C-3 position in 4,7-dihydroxy-1-indanone as a lower homologue of spirobisnaphthalenes are described herein. We investigated three approaches: 1) Nazarov cyclization of benzoylketene acetal, 2) intramolecular Friedel-Crafts acylation of naphtho[1,8-de]-1,3-dioxin-2-aryl-2-acetic acid chloride, and 3) double oxa-Michael addition of 1,8-dihydroxynaphthalene to 3-bromo-1-indenone. The last approach successfully afforded the natural product after the removal of acetates that serve as protecting groups for phenolic hydroxyls under acidic conditions.
Published online: 6th November, 2018
■ Atropisomeric and Conformational Properties of 6N-Benzoyl- and 6N-p-Tosyl-1,6-Benzodiazocines: Comparison with Those of 1,5-Benzodiazepines
Hidetsugu Tabata,* Kazuya Murai, Kaoru Funaki, Chihiro Takemae, Tomohiko Tasaka, Tetsuta Oshitari, Hideyo Takahashi,* and Hideaki Natsugari*
*Faculty of Pharma Sciences, Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
Abstract
The atropisomeric and conformational properties of the eight-membered 1,6-benzodiazocines (2) with 6N-benzoyl (A) and 6N-p-tosyl (B) groups were examined by comparing them with those of the seven-membered 1,5-benzodiazepine congeners (1) (A, B). The conformation (orientation) of the benzene ring in the benzoyl and tosyl groups differed depending on the ring size (7/8) and N-substituent (-CO-/-SO2-). The activation free-energy barrier to rotation of the axes in N-p-tosyl derivatives (B) was shown to be much higher than those of the benzoyl derivatives (A).
Published online: 20th April, 2018
■ A Convenient Synthesis of 2-(Alkyl(or Aryl)sulfanyl)-2H-1,4-benzothiazin-3(4H)-one Derivatives
Kazuhiro Kobayashi,* Kazuki Kawano, and Keita Yamashita
*Applied Chemistry Field, Chemistry and Biotechnology Course, Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan
Abstract
A convenient method for the preparation of 2-(alkyl(or aryl)sulfanyl)-2H-1,4-benzothiazin-3(4H)-one derivatives has been developed. Thus, methyl alkyl(2-{[(alkyl(or aryl)sulfanyl)methyl]sulfanyl}phenyl)carbamates, derived from commercially available 2-aminobenzenethiol by an easily operated three-step sequence, are treated with two equivalents of lithium diisopropylamide (LDA) to generate carbanions stabilized by the adjacent two sulfur atoms, which immediately undergo 2H-1,4-benzothiazin-3(4H)-one ring formation by intramolecular attack onto the carbamate carbonyl accompanying elimination of methoxide. In addition, direct or stepwise introductions of alkyl groups to the 2-position are reported.
Published online: 23rd May, 2018
■ Visible-Light-Promoted Se-Arylation of Diaryl Diselenides with 2-Phenylimidazopyridines in the Presence of Ammonium Iodide: Synthesis of 2-Phenyl-3-(arylselanyl)imidazo[1,2-α]pyridines
Yuki Murata, Keiko Kanasaki, Kaito Kondo, Naoki Kakusawa, Mio Matsumura, and Shuji Yasuike*
*School of Pharmaceutical Sciences, Aichi Gakuin University, 1-100 Kusumoto-cho Chikusa-ku Nagoya city 464-8650, Japan
Abstract
Photoreaction of diaryl diselenides and 2-phenylimidazo[1,2-a]pyridine in the presence of ammonium iodide (20 mol%) using blue LED light led to the formation of 3-(arylselanyl)imidazopyridines in good-to-excellent yields under aerobic conditions. By using various diselenides, this reaction efficiently introduces the selanyl group at the 3-position of the imidazopyridine scaffold.
Published online: 14th June, 2018
■ Efficient Synthesis of Methyl (S)-4-(1-Methylpyrrolidin-2-yl)-3-oxobutanoate as the Key Intermediate for Tropane Alkaloid Biosynthesis with Optically Active Form
Nanda Kumar Katakam, Cole W. Seifert, John D’Auria,* and Guigen Li*
*Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, U.S.A.
Abstract
Methyl (S)-4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate has been synthesized for enzymatic studies on cyclization enzymes during cocaine biosynthesis in Erythroxylum coca plants. During the present new synthesis, L-proline was first protected with Cbz group and reduced to chiral amino alcohol, which were then followed by Swern oxidation, Wittig reaction and decarboxylative condensation. At the last step, N-methylamino acid precursor was treated with 1,1’-carbonyldiimidazole followed by reacting with methyl potassium malonate to give the 3-oxobutanoate in 54% overall yield. This new strategy has proven to avoid obvious racemization of the L-proline chiral center during the synthesis. In addition, six of the eight synthesis steps were performed via GAP chemistry/technology without the use of column chromatography for purification.
Published online: 4th June, 2018
■ Total Synthesis of Haplacutines B and C
Noriki Kutsumura,* Keisuke Numata, Shiho Mosaki, and Takao Saito*
*Faculty of Science, Department of Chemistry, Tokyo University of Science, Kagurazaka 1-3, Shinjuku-ku, Tokyo 162-8601, Japan
Abstract
The total synthesis of 4-quinolone alkaloids, haplacutines B and C, has been achieved. The synthetic highlights are chemoselective construction of a 2-alkyl-4-quinolone skeleton via intramolecular base-promoted cyclocondensation of ortho-alkylamidoacetophenone and stereoselective elongation of the dienol side chain via the Stille coupling.
Published online: 23rd July, 2018
■ Lipase-Catalyzed Site-Selective Deacetylation of Sterically Hindered Naphthohydroquinone Diacetate and Its Application to the Synthesis of a Heterocyclic Natural Product
Riichi Hashimoto, Ayaka Sakakura, Kengo Hanaya, Shuhei Higashibayashi, and Takeshi Sugai*
*Department of Pharmaceutical Sciences, Faculty of Pharmacy, Keio University, 1-5-30 Shiba-Kouen, Minato-ku, Tokyo, Japan
Abstract
Lipase-catalyzed site-selective deacetylation of 2,5-dimethylnaphthalene-1,4-diol diacetate was examined. With Candida antarctica lipase B, the suppressing effect of a methyl substituent at the peri-position of the α-naphthyl ester over that at the ortho-position was significant. This site-selectivity was in contrast to that of chemical hydrolysis reported to date. From the resulting monoacetate, mansonone F, a physiologically active heterocyclic orthoquinone, was synthesized in 38% yield in as few as three steps.
Published online: 11th July, 2018
■ C-Glycosidation of Unprotected Aldopentoses with Ketones Using Proline-Triethylamine as Catalyst
Jithender Enukonda, Sherida Johnson, and Fujie Tanaka*
*Chemistry and Chemical Bioengineering Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa 904-0495, Japan
Abstract
Reactions of unprotected aldopentoses with ketones catalyzed by proline and triethylamine that afford C-glycoside derivatives are described.
Published online: 6th August, 2018
■ Site-Selective Synthesis of Acacetin and Genkwanin through Lipase-Catalyzed Deacetylation of Apigenin 5,7-Diacetate and Subsequent Methylation
Rie Fujita, Susanta Mandal, Kengo Hanaya, Mitsuru Shoji, Shuhei Higashibayashi, and Takeshi Sugai*
*Department of Pharmaceutical Sciences, Faculty of Pharmacy, Keio University, 1-5-30 Shiba-Kouen, Minato-ku, Tokyo, Japan
Abstract
Candida antarctica lipase B-catalyzed deacetylation proceeded with high site-selectivity on the C-4’ acetyl group in apigenin triacetate to give apigenin 5,7-diacetate. Methylation of the liberated hydroxy group with the combination of trimethyloxonium tetrafluoroborate (Meerwein reagent) and 1,8-bis(dimethylamino)naphthalene (proton sponge) in CH2Cl2 proceeded in a quantitative manner to give the product methylated at the C-4’ hydroxy group (acacetin 5,7-diacetate). Even with the same precursor, a different methylation product at the C-7 hydroxy group (genkwanin 4’,5-diacetate) was obtained in 86% yield by applying iodomethane and Cs2CO3 in dimethyl sulfoxide (DMSO). The methylated products were deprotected to form acacetin and genkwanin. We inferred that the latter unexpected methylation was ascribable to the intermolecular migration of an acetyl group from C-7 to C-4’. DFT calculations indicated that the C-7 phenoxide ion was 12.6 kJ/mol more stable than the initially formed C-4’ phenoxide ion.
Published online: 19th September, 2018
■ Formal Synthesis of Gephyrotoxin 287C
Katsuki Takashima and Naoki Toyooka*
*Graduate School of Innovative Life Science, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
Abstract
The enantioselective formal synthesis of (-)-gephyrotoxin 287C (1) has been achieved from octahydroquinolinone 8. The α, β-unsaturated ester 16, whose enantiomer was a key intermediate for the total synthesis of (+)-1, was synthesized by highly stereoselective Michael-type conjugate addition reaction to 8 and subsequent transformations.
Published online: 18th October, 2018
■ Studies toward the Synthesis of Perforatumone: Synthesis of the 7-Oxabicyclo[4.2.1]nonane-8,9-dione Core
Tatsuki Nakajima, Keita Takiguchi, Keisuke Yoshida, Akihiro Ogura, and Ken-ichi Takao*
*Department of Applied Chemistry, Keio University, Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
Abstract
Construction of the unique bridged bicyclic skeleton, 7-oxabicyclo[4.2.1]nonane-8,9-dione, of perforatumone was achieved. Key steps included a Dieckmann-type condensation, a Claisen rearrangement, and an intramolecular Michael reaction.
Published online: 19th October, 2018
■ Synthesis and DNA Cleavage Activity of Novel Spiro[cyclobutathiazole-4,4’-pyrazole] Derivatives
Eiichi Masumoto, Hayate Nagabuchi, Nobuhiro Kashige, Fumi Okabe-Nakahara, Fumio Miake, Kenji Yamagata, and Hiroshi Maruoka*
*Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
Abstract
A facile and efficient synthesis of novel spiro pyrazole derivatives containing cyclobutathiazole moiety is described. The key substrate pyrazole-thiazolidine derivative as the building block for bis-heterocycles was formed via a Knoevenagel-type condensation of thiazolidinedione with pyrazol-3-one. Thermal treatment of the pyrazole-thiazolidine derivative with orthoesters in refluxing toluene caused an C-attack nucleophilic substitution, followed by an intramolecular cyclization/elimination sequence, giving the corresponding spiro[cyclobutathiazole-4,4’-pyrazole] derivatives. All the synthesized compounds were characterized by spectroscopic analysis and were tested for their DNA cleavage activity in vitro.
Published online: 18th January, 2019
■ Enviromentally-Benign Glycosylation Reaction Using Odorless Thio-Glycosides and Hypervalent Iodine(III) Reagent
Koji Morimoto, Kana Yanase, Ibuki Odaka, Yasuyuki Kita,* and Tetsuya Kajimoto*
*Research Organization of Science and Technology, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga, 525-8577, Japan
Abstract
We discovered that the hypervalent iodine(III) reagent could mediate the glycosylation reaction by activating the thio-glycoside donors which were prepared from glycosyl 1-O-acetate and odorless p-octyloxybenzenethiol. By using this method, trisaccharides as well as disaccharides could be easily synthesized under mild reaction conditions. All the chemicals employed in this method are enviromentally-benign.
Published online: 19th October, 2018
■ Selective Aromatic Nucleophilic Substitution of 4-(Dimethylamino)-2-methoxy-3-(trifluoroacetyl)quinoline with Thiols – DFT Calculation Study
Norio Ota, Yusuke Harada, Yasuhiro Kamitori, and Etsuji Okada*
*Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
Abstract
The nucleophilic aromatic substitution proceeds exclusively at the 4-position of 4-(dimethylamino)-2-methoxy-3-(trifluoroacetyl)quinoline 1 by the reaction with various thiols to give the corresponding N-S exchanged products solely, and no O-S exchange reactions at the 2-position are performed. Our DFT calculation study provides a rational explanation regarding this complete selectivity based on energies of the adducts 6, 7 which are corresponding to the O-protonated Meisenheimer complexes at carbonyl oxygen in 3-trifluoroacetyl group. It was also investigated about influences of the solvents on the present unique selective substitution with thiols referring the results for the analogous selective substitution on 1 using amines as a nucleophile.
Published online: 16th October, 2018
■ Nucleophilic Addition to N-Benzoylisoquinolinium Cation Catalyzed by Sodium Tetracyanocyclopentadienides
Takeo Sakai,* Mai Hattori, Akari Tada, Junpei Matsuoka, and Yuji Mori
*Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
Abstract
Tetracyanocyclopentadienide-catalyzed nucleophilic addition to an N-benzoylisoquinolinium cation is reported. The reaction is accelerated by the in situ formation of the soluble lipophilic salt of an N-benzoylisoquinolinium cation and a tetracyanocyclopentadienide anion.
Published online: 17th October, 2018
■ Concise Synthesis of Anticancer Active trans-4-(4-Octylphenyl)prolinol
Junki Ando, Aoi Tazawa, Kohei Ishizawa, Minoru Tanaka,* and Hiroyoshi Takamura*
*Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan
Abstract
Concise synthesis of anticancer active trans-4-(4-octylphenyl)prolinol has been achieved. Regioselective iodination of aromatic compound and subsequent Suzuki–Miyaura cross-coupling with trans-1-octen-1-ylboronic acid produced the desired coupling product. Further transformation of this product afforded trans-4-(4-octylphenyl)prolinol. The synthesis of this anticancer compound has been performed with 23% overall yield and six steps, which have been improved in comparison with those (3.5% overall yield and eight steps) previously reported.