Special Issues

30 data found. 1 - 30 listed

Published online: 16th March, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)36
Oxidation of 1-Arylcyclohexa-2,5-dienes and Subsequent Double Michael Addition. A Rapid Access to the Büchi Ketone and the Pentacyclic Core of Aspidosperma Alkaloids

Dawood Hosni Ibrahim, Julie Dunet, Frédéric Robert, and Yannick Landais*

*Institute of Molecular Sciences, University of Bordeaux, 351 Cours de la Libération, F-33405 Talence Cedex, France


The Pd-catalyzed oxidation of 1-arylcyclohexa-2,5-dienes, resulting from a Birch reductive alkylation, leads to the corresponding arylcyclohexadienones. A careful choice of the substituents on the starting biaryl affords arylcyclohexadieonones, which may then enter into a double Michael addition, opening an access to the tetracyclic core of terpene indole alkaloids of the aspidosperma family. This strategy was used to prepare the Büchi ketone, a key-intermediate in the synthesis of this class of alkaloids, in 6 synthetic operations and 17% overall yield from commercially available 2-aminobiphenyl.


Published online: 15th March, 2018

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)29
Reactions of Pyruvate-Derived Dihydropyrans with Formaldehyde: Synthesis of Functionalized Furopyrans and Related Products

Pandurang V. Chouthaiwale, Ravindra D. Aher, and Fujie Tanaka*

*Chemistry and Chemical Bioengineering Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa 904-0495, Japan


Reactions that afford functionalized furopyrans and/or dimethylene derivatives from pyruvate-derived dihydropyrans and formaldehyde are described.

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Published online: 13th March, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)16
Synthesis and Biology of Dimeric, Trimeric and Tetrameric Analogues of Duocarmycin SA

Ravi Gandamala, Steven Hoekman, Mehrnoush Kangani, John E. Nidhiry, Kamala Penchalaiah, Dushant Singh, and Lutz F. Tietze*

*Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, D-37077 Göttingen, Germany


Novel dimeric, trimeric and tetrameric analogues of Durocarmycin SA have been prepared by the reaction of seco-CBI with di-, tri- and tetracarboxylic acid chlorides in the presence of a base in good yields. The highest bioactivity against cancer cells was observed for the compound obtained from the dicarboxylic acid.


Published online: 13th March, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)28
Synthesis and Photophysical Properties of 5-N-Arylaminothiazoles with Sulfur-Containing Groups on the Aromatic Ring at the 2-Position

Toshiaki Murai,* Hidenori Furukawa, and Kirara Yamaguchi

*Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University , 1-1 Yanagido, Gifu, Gifu 501-1193, Japan


5-Amino-2-(4-methylsulfanylphenyl)thiazoles were prepared by reacting 4-methylsulfanylbenzthioamides and N,N-diarylthioformamides. Demethylaiton of the resulting thiazoles gave 4-sulfhydrylphenylthiazoles. Starting from these thiazoles, a range of thiazoles with sulfur-containing functional groups were prepared. Oxidation of the thiazoles also gave thiazoles with sulfenyl and sulfonyl groups. The photophysical properties of a series of thiazoles were determined. The effects of sulfur-containing functional groups on the electronic structures of the thiazoles were elucidated by DFT calculations. Oxidation of the divalent sulfur atoms introduced to thiazoles helped to lower the energy levels of the LUMOs of the resulting thiazoles.


Published online: 9th March, 2018

Communication | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)54
Synthetic Study of Thermolides: Stereoselective Construction of the C10-C21 Fragment

Hikaru Yoshimura, Jun Ishihara, and Susumi Hatakeyama*

*Medical Innovation Center, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan


The C10-C21 fragment of nematocidal thermolides, macrocyclic PKS-NRPS hybrid metabolites isolated from a thermophilic fungus, was prepared in a highly stereoselective manner. The stereocontrol was accomplished by taking advantage of a cinchona alkaloid-catalyzed Morita-Baylis-Hillman reaction followed by diastereoselective hydrogenation and a cinchona alkaloid-catalyzed asymmetric β-lactone formation.

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Published online: 6th March, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)22
Synthesis of Tripeptides Containing Heterocyclic α-Amino Acids by using Heterospirocyclic 3-Amino-2H-azirines

Christoph Strässler, Anthony Linden, and Heinz Heimgartner*

*Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland


By using the ‘azirine/oxazolone method’, di- and tripeptides containing six-membered heterocyclic 4-amino-4-carboxylic acids with a piperidine, tetrahydropyran or tetrahydrothiopyran ring have been synthesized. It has been shown that the corresponding heterospirocyclic 3-(N-methyl-N-phenylamino)-2H-azirines are suitable synthons for these heterocyclic α-amino acids. As expected, the presence of these α,α-disubstituted α-amino acids stabilizes β-turn conformations in the prepared tripeptides of type Z-Phe-Xaa-Val-OR.


Published online: 5th March, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)42
β-Selective D-psicofuranosylation of Pyrimidine Bases and Thiols

Atsushi Ueda,* Yuri Nishimura, Yui Makura, Masakazu Tanaka, and Jun'ichi Uenishi

*Department of Molecular Medicinal Sciences, Graduate School of Biomedical Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan


N-Glycosidation of D-psicofuranosyl donor 1 with pyrimidine bases took place β-selectively in a β/α-ratio of 8:1 ~ 7:1. For S-glycosidation, 3,4-O-(3-pentylidene)-protected D-psicofuranosyl donor 15 was effective to increase β-selectivity up to 7:1.

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Published online: 2nd March, 2018

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)39
Synthesis of Phenol and Naphthol Derivatives fom Furfural

Kentaro Okano, Yuki Murase, Naoki Miyagawa, Kana Ashida, and Atsunori Mori*

*Chemical Science & Technology, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan


Synthesis of phenol and naphthol derivatives was performed from furfural derivatives through cycloaddition with an alkyne and benzyne, respectively. Lewis acid-promoted ring opening of the cycloadducts led to the formation of the corresponding phenol and naphthol derivatives. Amide-directed C–H alkenylation and arylation gave functionalized π-conjugated naphthalene derivatives.


Published online: 1st March, 2018

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)25
Synthesis of N-ω-Phenylalkyl-4-(p-Chlorophenyl)-Piperidin-4-ol Analogues with Potent Antiproliferative Activity Against HCT-116 Cells

Noriyuki Hatae,* Eiko Kujime, Keigo Yano, Mami Kizuka, Rina Ashida, Tominari Choshi, Takashi Nishiyama, Chiaki Okada, Tatsunori Iwamura, and Teruki Yoshimura

*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan


Some opioid analogues, such as morphine and loperamide, were reported to exhibit weak antiproliferative activity against tumor cells. In a study of loperamide analogues, we found that adding an N-ω-phenylalkyl group onto the 4-arylpiperidin-4-ol unit can have important effects on the antiproliferative activity of such compounds against HCT-116 cells. We optimized the distance between the phenyl group and 4-arylpiperidin unit to promote such activity.

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Published online: 26th February, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)30
A Short Synthesis of 9-Fluoroellipticine from 5-Fluoroindole

Deborah A. Davis and Gordon W. Gribble*

*6128 Burke Laboratory, Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, U.S.A.


A synthesis of 9-fluoroellipticine (1c) from 5-fluoroindole (6) is described that features the regioselective lithiation of 5-fluoro-1-(phenylsulfonyl)indole (7) followed by chemoselective acylation of 3,4-pyridinedicarboxylic anhydride. Subsequent cyclization of keto acid 9 to keto lactam 10 with acetic anhydride and sequential treatment of 10 with methyllithium and sodium borohydride affords 9-fluoroelllipticine.


Published online: 26th February, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)17
Derivatization of Secondary Aliphatic Alcohols to Picolinates – A New Option for Hplc Analysis with Chiral Stationary Phase

Keita Nishimura, Shuhei Tanabe, Riku Shinohara, and Yuichi Kobayashi*

*Department of Biomolecular Engineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Box B52, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan


Derivatization of secondary alcohols (R1R2CHOH) to benzoates has frequently employed to determine enantiomer ratios using HPLC with chiral stationary phase (CSP). However, a small difference in substituents (R1, R2) often results in insufficient separation. To find an alternative derivatization that detects such a small difference, picolinates (2-pyridyl-CO2CHR1R2) possessing Me/Et, Me/vinyl, Me/acetylenic, Et/n-Pr, and n-Pr/allyl substituents were prepared and separation efficiency was compared with that of benzoates (PhCO2CHR1R2). Eight commercially available CSPs containing carbamates or benzoates of cellulose and amylose were examined to find that retention factors (k'1 and k'2) and resolution (Rs) of picolinates were greater than those of the corresponding benzoates and that good to excellent Rs values (≥1.25) were recorded over a wide range of CSPs.

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Published online: 23rd February, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)27
Oxidative Rearrangement of Benzylamines To 4H-3,1-Benzoxazines via Cu/Mn-Promoted Intramolecular C–H Amination/Electrocyclic Reaction Cascade

Chiaki Yamamoto, Kazutaka Takamatsu, Koji Hirano,* and Masahiro Miura*

*Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan


We have developed a copper/manganese-mediated oxidative rearrangement of benzylamines to 4H-3,1-benzoxazines of potent interest in medicinal applications. The reaction proceeds uniquely through the initial copper/manganese-promoted intramolecular C–H amination giving benzazetidine intermediates and subsequent 4π electrocyclic ring opening/6π electrocyclic ring closing cascade. The key to success is the introduction of picolinamide-based N,N-bidentate directing group. The obtained benzoxazines can also be readily hydrolyzed to the corresponding 2-aminobenzyl alcohols, thus indicating that the overall transformations is regarded as the ortho-aminative rearrangement of benzylamines to benzylic alcohols.

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Published online: 22nd February, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)23
Phosphinic Acid-Promoted Addition of Isocyanides to 1-Methoxyisochroman Derivatives

Takahiro Soeta,* Syunsuke Matsuzaki, and Yutaka Ukaji*

*Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan


A synthetic method for preparation of isochroman-1-carboxylamides in good to high yields by addition of isocyanides to 1-methoxyisochroman derivatives in the presence of phosphinic acid was developed. A wide range of 1-methoxyisochroman derivatives and isocyanides were suitable for this reaction.

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Published online: 21st February, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)24
Formal Total Synthesis of (±)-Strictamine

Keigo Sato, Noriyuki Takanashi, Noriyuki Kogure, Mariko Kitajima, and Hiromitsu Takayama*

*Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan


A formal total synthesis of an akuammiline-type indole alkaloid, (±)-strictamine, which features ozonolysis, the Staudinger reaction, and the aza-Wittig reaction to construct its D-ring, is reported.


Published online: 14th February, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)20
Synthesis and Properties of Oligonucleotides Containing 3′-O,4′-C-Ethyleneoxy-bridged 5-Methyluridines

Takashi Osawa, Yuka Hitomi, Sawako Wakita, Han Kim, Masakazu Dohi, Masahiko Horiba, Yuta Ito, Satoshi Obika, and Yoshiyuki Hari*

*Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan


A phosphoramidite of 3ʹ-O,4ʹ-C-ethyleneoxy-bridged 5-methyluridine (3ʹ,4ʹ-EoNA-T) was successfully incorporated into oligonucleotides, and their abilities to form duplexes with RNA and DNA as well as triplexes with double-stranded DNA were evaluated. The stabilities of the duplexes formed between RNA and 3ʹ,4ʹ-EoNA-modified oligonucleotides were only slightly lower than those of the natural DNA–RNA duplex, while the duplexes formed between 3ʹ,4ʹ-EoNA-modified oligonucleotides and DNA were drastically less stable than the natural DNA–DNA duplex. Moreover, under the same conditions as the UV-melting experiments of the duplexes, 3ʹ,4ʹ-EoNA-modified oligonucleotides were unable to form triplexes with dsDNA. These results showed that oligonucleotides containing 3ʹ,4ʹ-EoNA-T had excellent RNA selectivity.


Published online: 9th February, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)18
Stereoselective Synthesis of a Pivotal Chiral Intermediate for Natural Salicylic Macrolides

Yoshihito Oguma, Nozomi Yamamoto, Kenji Sugimoto, and Yuji Matsuya*

*Graduate School of Medicine and Pharmaceutical Sciences for Research, University of Toyama, Sugitani 2630, Toyama, 930-0194, Japan


As a part of our ongoing research projects on the synthesis of natural salicylic macrolides, the optically active protected salicylate bearing the chiral diene substituent was required as a pivotal synthetic intermediate. The synthesis of the compound was achieved with a high optical purity starting from D-mannitol through Heck coupling reaction and terminal methylenation as key C–C bond forming reactions.


Published online: 9th February, 2018

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)12
Synthesis Of 2′(2′,6′)-(Di)Halogenoisoxazolopodophyllic Acids-Based Amides Derived from a Naturally Occurring Lignan Podophyllotoxin and their Acaricidal Activity

Bingchuan Zhang, Mingqiao Yu, and Hui Xu*

*Laboratory of Pharmaceutical Design & Synthesis, College of Life Sciences, Northwest A & F University, Xinong Road 22#, Yangling, Shaanxi, 712100, China


In continuation of our program to discover natural product-based pesticides, a series of 2′(2′,6′)-(di)halogenoisoxazolopodophyllic acids-based amides were prepared by structural modification of a naturally occurring lignan podophyllotoxin. Meanwhile, their acaricidal activity was evaluated against a typically crop-threatening agricultural insect pest, Tetranychus cinnabarinus. Among all derivatives, especially compounds 1012 displayed 4.8-7.4 folds more potent acaricidal activity than podophyllotoxin against T. cinnabarinus. This demonstrated that the carboxyl group at their C-2 position of 2′(2′,6′)-(di)halogenoisoxazolopodophyllic acids was very important for the acaricidal activity.


Published online: 7th February, 2018

Communication | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)15
Radical Cyclizations of Aryl Bromides for Synthesis of Cyclopenta[b]Indoles from Vince Lactam

Takumi Abe,* Tsuyoshi Morita, and Koji Yamada

*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan


Radical cyclizations of aryl bromides, synthesized in two steps from Vince lactam, afforded cyclopenta[b]indoles in good yields. Furthermore, an unprecedented method for constructing cyclopenta[b]indoles utilizing tricyclic intermediate was also explored.


Published online: 2nd February, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-18-S(T)19
Total Synthesis of Phenanthroquinolizidine Alkaloid Cryptopleurine and Phenanthroindolizidine Alkaloid Tylophorine

Yousuke Yamaoka,* Marie Taniguchi, Ken-ichi Yamada, and Kiyosei Takasu*

*Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida-shimoadachi-machi, Sakyo-ku, Kyoto 606-8501, Japan


Total synthesis of phenanthroquinolizidine alkaloid cryptopleurine was achieved in 11 steps from commercially available 6-bromoveratraldehyde. The crucial step of phenanthrene construction is a formal [2 + 2] cycloaddition of 2-acyl-2’-vinyl-1,1'-biaryl, followed by an acid promoted ring-contraction/ring-opening sequence. The key point to complete the total synthesis of cryptopleurine is use of nosyl amide as a nucleophile for cyclization of piperidine ring. The synthesis of tylophorine was also achieved in the similar manner.

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Published online: 2nd February, 2018

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)13
One-pot Synthesis of (Z)-N-Substituted Isobenzofuran-1(3H)-Imines from Secondary Benzothioamides and Carbonyl Compounds

Kazuhiro Kobayashi* and Takashi Nogi

*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


An efficient one-pot methodology for the synthesis of (Z)-N-substituted isobenzofuran-1(3H)-imines starting from secondary benzothioamides has been developed. The reaction of the starting materials with two equivalents of butyllithium generated 2,N-dilithio-N-alkyl(or aryl)benzothioamides, which were then allowed to react with carbonyl compounds to give, after aqueous treatment, the desired products in satisfactory yields.


Published online: 26th January, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)14
Activation of 1-Methyl-5-Nitro-2-Pyrimidinone by Dearomatization using a Secondary Amine

Haruyasu Asahara, Azusa Yasuoka, and Nagatoshi Nishiwaki*

*School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada-cho, Kami, Kochi, 782-8502, Japan


Electron-deficient 1-methyl-5-nitro-2-pyrimidinone is easily attacked by methanol or pyrrolidine to afford the corresponding adducts, respectively, by which aromaticity of nitropyrimidinone is lost. Indeed, the amine-adduct exhibited higher reactivity than that of original structure to facilitate the reaction with 1,3-dicarbonyl compound leading to diazabicyclic compound at room temperature. The amine-adduct also underwent the ring opening reaction to furnish nitroenamines with (Z)-configuration.

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Published online: 23rd January, 2018

Communication | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)9
Fine Chemicals from a Biomass-Derived Dicarboxylic Acid: Chiral Bisoxazolines and Their Application in Enantioselective Diels-Alder Reactions

Sermadurai Selvakumar, Alisa Fairweather, Angel Ugrinov, and Mukund P. Sibi*

*Department of Chemistry, North Dakota State University, Fargo, North Dakota, 58105-5516, U.S.A.


2,5-Furandicarboxylic acid (FDCA) is a feedstock chemical readily available from cellulosic biomass. Six chiral bisoxazolines varying in the steric size of the blocking group have been synthesized from FDCA in modest to good overall yields. The effectiveness of the new chiral bisoxazolines has been evaluated in enantioselective Diels-Alder reactions.

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Published online: 23rd January, 2018

Paper | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)11
Research on Unique Masked ortho-Benzoquinone, Monohemiaminal: Synthesis and Reactions

Yuri Matsumoto, Akihiko Nakamura, Emi Saito, and Masahisa Nakada*

*Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan


Synthesis of ortho-benzoquinone monohemiaminals via the oxidative dearomatization/O-cyclization cascades of phenols bearing an ortho substituent derived from an amino alcohol with PIDA is described. The cascade reactions of substrates bearing a chiral substituent were found to proceed in a stereoselective manner. The Diels-Alder reactions of the ortho-benzoquinone monohemiaminals proceed in a highly stereoselective manner. The oxidative dearomatization/O-cyclization cascade affording the ortho-benzoquinone monohemiaminal had never been reported; hence, there is still ample scope for further investigation.

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Published online: 23rd January, 2018

Communication | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)10
Synthesis of 6/6/6-Tricyclic Ether System via Achmatowicz and Intramolecular Oxa-Michael Reactions

Hiroki Yamamoto, Kohei Torikai, Makoto Ebine, and Tohru Oishi*

*Department of Chemistry, Faculty and Graduate School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan


Synthesis of 6/6/6-tricyclic ethers possessing 1,3-diaxial methyl groups was examined via Achmatowicz reaction and intramolecular oxa-Michael reaction. A key precursor was prepared via coupling of an aldehyde with a furyllithium derivative followed by radical deoxygenation of the resulting secondary alcohol. The intramolecular oxa-Michael reaction proceeded in a stereoselective manner to afford cis-fused product as a single isomer.

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Published online: 28th December, 2017

Communication | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)7
Enantioselective Cycloadditions between Aliphatic Nitrile Oxides and 2-Hydroxystyrenes Catalyzed by Chiral Amine-Urea

Yasunori Toda, Masato Koyama, Hiroyoshi Esaki, Kazuaki Fukushima, and Hiroyuki Suga*

*Department of Materials Chemistry, Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan


Chiral amine-urea-catalyzed enantioselective 1,3-dipolar cycloadditions of nitrile oxides with 2-hydroxy-3-methoxystyrene are described. Aliphatic aldehyde-derived hydroximoyl chlorides were used as nitrile oxide precursors, providing optically active isoxazolines with moderate to good enantioselectivities.

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Published online: 26th December, 2017

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)8
Stereoinversion of a Tertiary Alcohol on a THP Ring: a Recovery Route to an Intermediate for Gymnocin-A

Takeo Sakai, Kayo Aoyama, Rie Oshima, Kyoko Furukawa, and Yuji Mori*

*Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan


The stereoinversion of a tertiary alcohol on a tetrahydropyran ring was achieved through a five-step sequence including regioselective dehydration, diastereoselective epoxidation and reduction. This approach offers a recovery route from the diastereomer to the desired tertiary alcohol as part of the synthesis of gymnocin-A.

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Published online: 19th December, 2017

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)6
Concise Approach to Mono- and Disubstituted Luotonin A Analogs and Their Cytotoxicity Test

Natsuko Kagawa,* Kimiko Nishimura, Shinya Abe, Takashi Masuko, and Masahiro Toyota*

*Department of Chemistry, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan


A concise approach for the preparation of luotonin A analogs has been developed. The new synthetic route contains an anion-assisted intramolecular double hetero Diels ̶ Alder reaction and a direct oxidative cross coupling reaction. Some synthetic luotonin A analogs show cytotoxic activities against Daudi and Jurkat human cancer cells as potent as camptothecin.

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Published online: 18th December, 2017

Paper | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)2
Synthesis of Substituted t-Butyl 3-Alkyl-oxindole-3-carboxylates from Di-t-Butyl (2-Nitrophenyl)malonates

Yusuke Yamai, Akio Tanaka, Tatsuo Yajima, Kyoji Ishida, Itaru Natsutani, Shinichi Uesato, Yasuo Nagaoka, and Takaaki Sumiyoshi*

*Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680, Japan


Using a novel tandem reduction-cyclization, we synthesized t-butyl 3-alkyloxindole-3-carboxylates from the di-t-butyl 2-alkyl-2-(2-nitrophenyl)-malonate. Introduction of an α-substituent to the di-t-butyl 2-(2-nitrophenyl)-malonates and addition of acid promoted reactivity. This methodology was successfully applied to gram-scale-synthesis of the t-butyl 3-methyloxindole-3-carboxylate 1 and 3-hydroxymethyl-3-methyloxindole 2 without silica gel column chromatography.

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Published online: 17th November, 2017

Paper | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)1
Asymmetric Total Synthesis and Structure Confirmation of (+)-(3E)-Isolaurefucin Methyl Ether

Te-ik Sohn, Byungsook Kim, Deukjoon Kim,* and Robert S. Paton

*The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Shillim-Dong, San 56-1, Kwanak-Gu, Seoul 151-742, Korea


An asymmetric total synthesis and structure confirmation of (+)-(3E)-isolaurefucin methyl ether (2a) was accomplished. Our synthesis features two complementary routes to construct the α,α’-trans-2,8- dioxabicyclo[5.2.1]decane skeleton of the natural product from α,α’-trans-γ,δ-unsaturated oxocene alcohol 7, namely, an intramolecular epoxide opening route and a novel methoxyetherification route based on organoselenium- mediated oxonium ion formation/fragmentation. A computational analysis was performed to model the observed different fragmentation behaviors of the respective oxonium ions 8 and 8’ derived from α,α’-trans- and α,α’-cis-γ,δ-unsaturated oxocene alcohols 7 and 7’ during the organoselenium-mediated oxonium ion formation/fragmentation. Regarding the possibility of the natural product being an artifact, the reactivity of chlorofucin surrogate 16 and neoprelaurefucin surrogate 16’ during methanolysis was compared, the results were in good agreement with calculations.

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Published online: 17th November, 2017

Paper | Special issue | Prepress
DOI: 10.3987/COM-17-S(T)3
Polymeric Silver(I) Complexes Based on Bidentate Imidazoline-2-thiones Synthesis and Crystal Structures

Barbara Rietzler, Gerhard Laus, Klaus Wurst, Thomas Gelbrich, Sven Nerdinger,* Erwin Schreiner, and Herwig Schottenberger

*Sandoz GmbH, Biochemiestrasse 10, 6250 Kundl, Austria


The bidentate ligand 1,6-bis(1-methylimidazol-2-ylthio)hexane or its hexafluoride salt reacted with silver(I) triflate, nitrate or oxide, respectively, to give the corresponding polymeric silver(I) complexes. Three crystal structures have been determined and showed linear and cyclic motifs.

30 data found. 1 - 30 listed