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7 data found. 1 - 7 listed

Published online: 22nd June, 2018

Communication | Regular issue | Prepress
DOI: 10.3987/COM-18-13927
Synthesis of an Anlog of Amphidinol 3 Corresponding to the C31–C67 Section

Tomoyuki Koge, Yuma Wakamiya, Makoto Ebine, and Tohru Oishi*

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

Abstract

An artificial analog corresponding to the C31–C67 section of amphidinol 3 (AM3) was designed as a part of the structure–activity relationship studies to elucidate structure requirements for eliciting antifungal activity. To reduce the number of synthetic steps, the 43-deoxy-51-epi derivative containing common tetrahydropyran ring system was designed and synthesized from a pivotal intermediate in 17 steps. The analog elicited no antifungal activity, suggesting that not only the two tetrahydropyran rings, but also polyol section of AM3 are necessary to elicit antifungal activity.

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Published online: 19th June, 2018

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-13910
Synthesis of Bicyclo[2.2.2]octadiene-Fused Sapphyrins and Their Thermal Conversion

Tetsuo Okujima,* Toshiki Abe, Shigeki Mori, Takahiro Nakae, and Hidemitsu Uno

*Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan

Abstract

A series of sapphyrins fused with bicyclo[2.2.2]octadiene were successfully synthesized via [3+1+1] porphyrinoid synthesis. The retro DielsAlder thermal conversion afforded the corresponding di-, tri-, tetra-, and pentabenzosapphyrins.

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Published online: 14th June, 2018

Review | Regular issue | Prepress
DOI: 10.3987/REV-18-885
Developments toward the Production of Diverse Natural-Product-Like Compounds: Diversity-Oriented Synthesis and Diversity-Enhanced Extracts

Haruhisa Kikuchi* and Yoshiteru Oshima*

*Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan

Abstract

Natural products and their derivatives have proven very useful in the search for biologically active compounds and in the development of new drugs because of their structural diversity. However, new approaches that may increase the chemical diversity of such natural products must be developed in order to retain the future usefulness of these compounds. Diversity-oriented synthesis (DOS) has recently emerged as an efficient methodology for constructing complex and diverse compounds from simple and similar precursors. Through the combination of natural product chemistry and DOS, we therefore propose a new approach, diversity-enhanced extracts, for increasing the diversity of natural-product-like compounds. This review describes recent developments toward the production of diverse natural-product-like compounds by DOS based on natural products and direct chemical derivatization of natural extracts, including diversity-enhanced extracts.

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Published online: 13th June, 2018

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-13923
Synthesis of (E)-N-Substituted 1,2-Benzothiazol-3(2H)-imine 1,1-Dioxide Derivatives from Secondary Benzenesulfonamides and Isothiocyanates

Kazuhiro Kobayashi* and Daiki Fujiwara

*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 new and simple method for the preparation of (E)-N-substituted 1,2-benzothiazol-3(2H)-imine 1,1-dioxide derivatives has been developed. 2,N-Dilithiobenzenesulfonamides, generated by the treatment of secondary benzenesulfonamides with two equivalents of butyllithium, react with isothiocyanates to afford the corresponding 2-(aminosulfonyl)benzothioamides, which undergo ring closure with a formal elimination of hydrogen sulfide on treatment with thionyl chloride in the presence of two equivalents of pyridine to provide the desired products. Acid hydrolysis of some of these products leads to the formation of N-substituted saccharins.

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Published online: 12th June, 2018

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-13912
Synthesis and Electrochemical Properties of 2,2’-Biguaiazulene-Based 1,2-Dithiin and Thiophene

Ohki Sato* and Ryuto Sakai

*Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan

Abstract

The synthesis of diguaiazuleno[3,2-c:2’,3’-e][1,2]dithiin was achieved by the reaction of 2,2’-biguaiazulene with disulfur dichloride/imidazole as a sulfuration reagent. Thermolysis of the dithiin afforded the corresponding desulfurized compound, diguaiazuleno[3,2-b:2’,3’-d]thiophene. Cyclic voltammetry of the S-heterocycles showed one reversible wave at the reduction region, respectively.

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Published online: 30th May, 2018

Review | Regular issue | Prepress
DOI: 10.3987/REV-18-882
Eudistomin U, Isoeudistomin U, and Related Indole Compounds: Synthesis and Biological Activity

Alexandra A. Kolodina and Olga V. Serdyuk*

*Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Nikolaus-Fiebiger-Str. 10, Erlangen 91058, Germany

Abstract

Eudistomin U and isoeudistomin U are important derivatives of β-carboline, tryptophan-derived metabolites. These natural products and related 2-substituted 1,2,3,4-tetrahydroeudistomins U demonstrate antibacterial, antimalarial, and anticancer activities, as well as a DNA-binding ability and strong KSP inhibition, that makes them very attractive targets for synthetic chemists. This manuscript highlights advances in the synthesis of eudistomin U, isoeudistomin U, their derivatives, and related compounds bearing an indole unit. A detailed discussion of biological activities, including structure-activity relationships, and future prospects, are also presented.

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Published online: 8th May, 2018

Review | Regular issue | Prepress
DOI: 10.3987/REV-18-884
Synthesis of Nitrogen Containing Heterocycles by Using Carbon-Nitrogen Double Bond

Kentaro Okuma*

*Department of Chemistry, Faculty of Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan

Abstract

Recent achievements in the construction of mainly nitrogen containing heterocycles by the intramolecular cyclization of alkenylanilides via activation of unsaturated bonds are reviewed. NIS or ZnX2 activation of 2-alkenylanilines and 2-alkynylanilines gave quinolines or indoles in high yields. Reaction of 2-aminobenzaldehyde with acetophenones under basic conditions gave dibenzonaphthyridines in one-pot operation. Other nitrogen and chalcogene containing heterocycles were also synthesized by the reaction of ketone hydrazones with chalcogen halides

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7 data found. 1 - 7 listed