Prepress

Regular & Special Issues

41 data found. 31 - 41 listedFirst Previous

Published online: 13th May, 2020

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)11
Synthesis of Pyrrolo[1,2-c]Pyrimidines

Easha Narayan, Liangfeng Fu, and Gordon W. Gribble*

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

Abstract

The synthesis of several new pyrrolo[1,2-c]pyrimidines from the base-induced condensation of pyrrolo-2-carbaldehydes with either TosMIC (toluenesulfonylmethyl isocyanide) or ethyl isocyanoacetate is described, along with the preparation of novel bis(pyrrolo[1,2-c]pyrimidines).

FREE:PDF (314KB)

Published online: 13th May, 2020

Short Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)5
Conjugate Addition Reaction of Indole to Protected 2-Amino-1-Nitroethenes Mediated by Silica Gel

Kenichi Murai,* Shuji Miyazaki, and Hiromichi Fujioka*

*Graduate School of Pharmaceutical Science, Osaka University, 1-6 Yamadaoka, Suita, Osaka 560-0871, Japan

Abstract

We have developed a silica-gel-mediated route for the conjugate addition of indole to protected 2-amino-1-nitroethenes for the synthesis of 1-indolyl-1,2-ethanediamines. This is the first demonstration of indole as the nucleophile for addition to protected 2-amino-1-nitroethenes.

FREE:PDF (667KB)

Published online: 12th May, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)8
Concise Preparation and Biological Evaluations of 9-cis-Retinoic Acid Analogues Having an Aromatic Ring

Takashi Okitsu,* Kinya Iwatsuka, Kimie Nakagawa, Toshio Okano, and Akimori Wada*

*Faculty of Pharmaceutical Science, Kobe Pharmaceutical University, 4-19-1, Motoyamakita, Higashinada, Kobe 658-8558, Japan

Abstract

A series of 9-cis-retinoic acid analogues having an aromatic ring were prepared in only two steps, and were evaluated for transcriptional activities with retinoic acid response element (RARE) and retinoid X response element (RXRE). Among them, compound 6c, bearing a 2-naphthyl substituent, exhibited the highest transcriptional activity with RXR selectivity.

FREE:PDF (781KB)

Published online: 8th May, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-19-924
New and Practical Applications of Functionalized Cyclotriphosphazene Core-Based Materials

Manabu Kuroboshi* and Hideo Tanaka

*Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka 3-1-1, Kita-ku, Okayama, 700-7530, Japan.

Abstract

Hexachlorocyclotriphosphazene (HCCP) is a very old compound, and used as a starring material of a variety of cyclotriphosphazene derivatives. Some of them have unique properties, and have been used in not only frame retardants but also functional materials and biomaterials. To develop cyclotriphosphazene derivatives having a desired function, numbers of substituents, regio-, and stereochemistry should be controlled in the reaction between HCCP and nucleophiles. In this review, selectivity in the reaction between HCCP and nucleophiles as well as application of the cyclotriphosphazene derivatives are summarized.

FREE:PDF (4.9MB)

Published online: 8th May, 2020

Communication | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)6
Synthesis of Lactone-Fused Cyclopropanes by Ring Contractive α-Ketol Rearrangement of Ketal-Fused Cyclobutanones

Kiyosei Takasu,* Koichi Shigenaga, Kazuma Shimoda, Hiroshi Takikawa, and Yousuke Yamaoka

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

Abstract

Ring contraction of cyclic silyl ketal-fused cyclobutanones into lactone-fused cyclopropanes under desilylative conditions is described. The reaction affords 1-hydroxy- and 1-amino-1-cyclopropanecarboxylic acid derivatives from cyclobutanone substrates and their imine congeners, respectively.

FREE:Supporting Info. (4.6MB)PDF (812KB)

Published online: 28th April, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)3
Thermally-Induced Doping of The Regioregular Polythiophene Bearing Alkylene Spacered Benzene Sulfonate Group at The Side Chain

Chihiro Kubota, Daisuke Morita, Keisuke Fujita, Sonoka Yamamoto, Toyoko Suzuki, Kentaro Okano, Masahiro Funahashi, Masaki Horie, and Atsunori Mori*

*Department of Chemical Science and Engineering, Kobe University, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan

Abstract

Regioregular polythiophene bearing a benzenesulfonate group, which involved an alkylene spacer between thiophene and benzene ring, was synthesized. The obtained polythiophene was shown to improve its conductivity by heating the polymer thin film through the transformation of the ester group into the corresponding sulfonic acid.

FREE:PDF (569KB)

Published online: 27th April, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-928
Recent Advances in the Total Synthesis of Clavilactones

Akihiro Ogura and Ken-ichi Takao*

*Department of Applied Chemistry, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, Japan

Abstract

Clavilactones are meroterpenoids containing a 10-membered carbocycle fused to an α,β-epoxy-γ-lactone and a hydroquinone or benzoquinone. This review describes the total synthesis of clavilactones achieved by four research groups, focusing on their innovative synthetic strategies.

FREE:PDF (724KB)

Published online: 17th April, 2020

Paper | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)1
Synthesis of Probe Molecules, 6-(Dimethylamino)-2-Phenylisoindolin-1-Ones, for Mechanistic Studies of Firefly Luciferase Inhibition

Medha J. Gunaratna, Bo Hao, Man Zhang, Madoka Nakagomi, Ai Ito, Takeo Iwamoto, and Duy H. Hua*

*Department of Chemistry, Kansas State University, Manhattan, KS 66506, U.S.A.

Abstract

Firefly luciferase is used in high-throughput screening based on the detection of chemiluminescence. It catalyzes an esterification reaction of luciferin with adenosine 5’-triphosphate (ATP) followed by decarbonylation with oxygen and concomitance of light. Previously, we reported that firefly luciferase also possesses acyl-CoA synthetase activity and catalyzes an aromatic carboxylic acid group of F-53, using ATP, Mg2+ and coenzyme A (CoA), to produce F-53 covalently attached to active-site lysine-529 residue of firefly luciferase through the formation of an amide group. The amidation of lysine-529 resulted in a deactivation of luciferase. In order to probe firefly luciferase inhibition’s mechanism, we synthesized two probe molecules 1 and 2, mimicking F-53. Molecule 1 contains an azido-appended side chain in the aromatic ring of F-53, while 2 possesses an azido and a carboxylic acid group appended side chains. Both synthetic schemes are readily amenable to large-scale syntheses. Molecule 1 was made from 2-allylaniline, which was derived from a thermal-induced aromatic-Claisen rearrangement of N-allylaniline. The azido-appended side chain of 2 was installed from a Horner-Wadsworth-Emmons reaction and the carboxylic acid side chain from a Sonogashira reaction.

FREE:PDF (558KB)

Published online: 16th April, 2020

Communication | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)4
Synthetic Studies on Densanins: Stereoselective Construction of A Pyrrolidine Ring Containing a Quaternary Carbon

Kyosuke Ueda and Satoshi Yokoshima*

*Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan

Abstract

We disclose our synthetic studies on densanins, which feature the stereoselective cycloaddition of a cycloheptenone and an azomethine ylide to construct a pyrrolidine ring containing a quaternary carbon

FREE:Supporting Info. (5.1MB)PDF (459KB)

Published online: 9th April, 2020

Review | Regular issue | Prepress
DOI: 10.3987/REV-20-927
5,15-Diheteroporphyrins Synthesized from α,α'-Dihalodipyrrin as a Key Building Block

Soji Shimizu*

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

Abstract

A facile synthesis of meso-aryl-substituted α,α'-dihalodipyrrins and their use as starting materials in the porphyrin synthesis have enabled creation of various porphyrin analogues containing heteroatoms at two opposite meso-positions, namely 5,15-positions. Incorporation of lone pair electrons into the 18π-electron aromatic conjugated system of porphyrin allows the system to attain antiaromaticity with unique optical and electrochemical properties. This review summarizes the recent development in the chemistry of 5,15-diheteroporphyrins synthesized from meso-aryl-substituted α,α'-dihalodipyrrins.

FREE:PDF (10.6MB)

Published online: 16th March, 2020

Communication | Special issue | Prepress
DOI: 10.3987/COM-20-S(K)2
5-Arylidenetetronate as A Versatile Electrophore for Pi-Extended Electron Acceptors

Yuki Hayashi, Yusuke Ishigaki, Jérémy Merad, Takanori Suzuki,* and Maurice Médebielle*

*Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan

Abstract

Bis[4-methoxy-5-methylenefuran-2(5H)-one]-type electron acceptors with anthracene-9,10-diyl and thiophene-2,5-diyl spacer were prepared by one-pot condensation of methyl tetronate with the corresponding dialdehydes. They undergo reversible electrochemical reduction, thus showing the potential utility of 5-arylidenetetronate as an electrophore for developing novel electron acceptors.

FREE:Supporting Info. (420KB)PDF (864KB)
41 data found. 31 - 41 listedFirst Previous