HETEROCYCLES

■ Contents

■ Reaction of Arynes with Carbon-Heteroatom Double Bonds

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 heterocycles by the reaction of arynes with carbon-heteroatom double bonds are reviewed. Use of the Diels-Alder type, ionic, and radical mechanisms resulted in the formation of novel heterocycles containing oxygen, nitrogen, sulfur, and selenium atoms.

■ Application of Nanomaterials in Heterocyclic Chemistry

Majid M. Heravi* and Tooba Alishiri

*Department of Chemistry, School of Sciences, Alzahra University, Vanak, Tehran, Iran

Abstract

This review focused on the application of nano-materials in heterocyclic chemistry. The main part of review is constituted by sections in which the reactions catalyzed by nanomaterials. In the last part of this review, emphasis is given to the heterocyclic supported nanomaterials and their importance in the catalysis.

■ Total Synthesis of Aspergillides A, B, and C

Tomohiro Nagasawa and Shigefumi Kuwahara*

*Graduate School of Agricultural Science, Tohoku University, 1-1, Tsutsumidori, Amamiya, Aoba-ku, Sendai, 981-8555, Japan

Abstract

Aspergillides A, B, and C are cytotoxic macrolides produced by the marine-derived fungus Aspergillus ostianus strain TUF 01F313. The unique molecular architectures of the aspergillides featuring 14-membered marocyclic structures embedded with a tetrahydro- or dihydropyran unit have attracted significant attention from the synthetic chemistry community, and thereby various synthetic approaches to these structurally as well as pharmacologically intriguing molecules have been reported by as many as 12 research groups in the past 3 years. This review describes all of the syntheses disclosed to date, focusing mainly on the methodologies employed for the diastereoselective installation of the pyran ring systems.

■ Reusable Polymer-Supported 2,2’-Biarylpyridine-Copper Complexes for Huisgen [3+2] Cycloaddition in Water

Toshimasa Suzuka,* Yamato Kawahara, Kazumasa Ooshiro, Takuya Nagamine, Kazuhito Ogihara, and Matsutake Higa

*Department of Chemistry, Biology and Marine Sciences, Faculty of Science, University of Ryukyus, Nishihara-cho, Okinawa 903-0213, Japan

Abstract

Polymer-supported 2,2′-biarylpyridine–copper complexes were prepared and found to promote the Huisgen [3+2] cycloaddition reaction between azides and alkynes in water to give the corresponding triazoles in up to 95% isolated yield. The catalyst was recovered and reused several times without any loss in catalytic activity. ICP-AES analysis of the aqueous phase revealed barely detectable levels of copper residue.

■ New Route to Novel Polysubstituted Quinolines Starting with Eugenol, the Main Constituent Ocimum sanctum L. Oil

Nguyen Huu Dinh,* LeVan Co, Nguyen Manh Tuan, Le Thi Hong Hai, and Luc Van Meervelt

*Department of Chemistry, Hanoi National University of Education, 136 Xuanthuy Hanoi, Vietnam

Abstract

An efficient and simple method has been reported for the synthesis of (6-hydroxy-3-sulfoquinolin-7-yloxy)acetic acid (Q1) starting with eugenol, the main constituent of Ocimum sanctum L. oil. The reaction pathway from a quinone-aci compound to the quinoline compound Q1 was proposed on the basis of 1H NMR method. Q1 was used as a key compound for further transformation to 9 novel polysubstituted quinolines. The structure of the synthesized compounds was characterized by spectroscopic methods.

■ Efficient Synthesis of 2,4-Diarylquinolines via Fe(III) Trifluoroacetate Catalyzed Three-Component Reactions under Solvent-Free Conditions

Min Zhang,* Ting Wang, Biao Xiong, Fengxia Yan, Xiaoting Wang, Yuqiang Ding, and Qijun Song

*School of Chemistry and Materials Engineering, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu Province, 214122, China

Abstract

A convenient and efficient one-pot synthesis of 2,4-diarylquinolines is described by using Fe(CF3CO2)3 as a catalyst for the first time. In this method, three-component coupling of arylaldehydes, arylamines and arylacetylenes furnished the corresponding products in good to excellent yields. The work features the use of cheap and eco-friendly catalyst, excellent functional group tolerance and solvent-free conditions. A variety of new products were afforded effectively.

■ Cytotoxic Xanthone Glycosides from Aerial Part of Centaurium spicatum

Ahmed E. Allam, Mohamed A. El-Shanawany, Enaam Y. Backheet, Alaa M. Nafady, Fumihide Takano,* and Tomihisa Ohta

*Department of Pharmacognosy and Chemistry of Natural Products, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan

Abstract

A new xanthone glycoside, 8-hydroxy-3,5-dimethoxy-1-O-[α-L-arabinofuranosyl-(1→6)-β-D-glucopyranosyl]-xanthone (1) in addition to two known xanthones named 8-hydroxy-3,5-dimethoxy-1-O-β-D-glucopyranosyl-xanthone (2) and 1,8-dihydroxy-3,5-dimethoxyxanthone (methylbellidifolin) (3) were isolated from the methanol extract of aerial part of Centaurium spicatum, and tested for their cytotoxic activities against three different types of cell lines HeLa, THP-1and HL-60 cell lines. All compounds showed cytotoxicities to all cell lines, whereas showed a moderate activity against human monocytic cell line HL-60. Among three tested xanthones, the cytotoxic activity of compound 1 was stronger than those of other xanthones and the IC50 values for compound 1 were 3.22 (against THP-1), 8.67 (against HeLa) and 74.6 (against HL-60) µM, respectively.

■ Caulerchlorin, a Novel Chlorinated Bisindole Alkaloid with Antifungal Activity from the Chinese Green Alga Caulerpa racemosa

Ding-Quan Liu, Shui-Chun Mao,* Xiao-Qing Yu, Li-Hua Feng, and Xiao-Ping Lai

*Department of Pharmacy, Nanchang University, 461 Bayi Road, Nanchang, Jiangxi Province 330006, China

Abstract

Caulerchlorin (2), a novel chlorinated bisindole alkaloid with an eight-membered cyclic ring between two indole rings incorporated directly with a chlorine atom, together with three known related metabolites, caulerpin (3), monomethyl caulerpinate (4), and caulersin (5), has been isolated from the Chinese green alga Caulerpa racemosa (Forssk.) J. Agardh. The structure of 2 was determined on the basis of extensive spectroscopic analysis. Compounds 2–5 were evaluated for their antifungal activity against Candida albicans (SC5314), Candida albicans (Y0109), Candida parapsilosis (ATCC 22019), Candida glabrata (537), Microsporum gypseum (Cmccfmza), Trichophyton rubrum (Cmccftla), Aspergillus fumigatus (07544), and Cryptococcus neoformans (32609), and the result showed that only compounds 2 and 4 had a moderate/weak antifungal activity against Cryptococcus neoformans (32609) with MIC80 values of 16 and 64 μg mL-1, respectively.

■ A Novel Solid-Phase Synthesis of Quinolines

E Tang,* Deshou Mao, Wen Li, Zhangyong Gao, and Pengfei Yao

*School of Chemical Science and Technology, Yunnan University, No. 2 Green Lake North Road, Kunming 650091, China

Abstract

A method for synthesizing substituted-quinolines using TMSOTf-catalyzed polystyrene-supported succinimidyl selenide-induced intramolecular seleno-arylation of tethered alkenes as a key step has been developed. The catalytic process provides an efficient method for the stereoselective and regioselective synthesis of tetrahydroquinoline possessing a seleno-functionality, followed by deprotection of tosyl group and syn-elimination of selenoxides to provide quinolines in good yields and purities.

■ Synthesis of Analogues of Makaluvamine A

Sébastien Bouclé and Jérôme Guillard*

*EA 3857 Laboratoire de Synthèse et Physicochimie, Organique et Thérapeutique, UFR des Sciences Pharmaceutiques, University of Tours, 31 Avenue de Monge, 37200 Tours, France

Abstract

A new and efficient synthesis of tricyclic pyridoquinonoxalinone 1 an analog of Makaluvamine A and its intermediates 2 and 3 has been developed starting from 5,8 dimethoxy-4,4 dimethyl[1,2,3,4]tetrahydroquinoline 4. The synthesis was accomplished in 11 steps and 4% overall yield from commercially available 2,5-dimethoxyaniline.

■ New Dihydroagarofuranoid Sesquiterpenes from Celastrus angulatus

Jiang-yun Liu, Bei-bei Tan, Xue-long Gong, Qiong-ming Xu,* Xiao-fei Sun, Pei-lie Cai, and Shi-lin Yang

*School of Pharmacy, Soochow University, Suzhou 215123, China

Abstract

Three new highly esterified β-dihydroagarofuran sesquiterpenes (1-3) were isolated from the root barks of Celastrus angulatus Max. together with eight (4–11) known ones. The new compounds were identified as 1β-picolinoyloxy-2β,6α-diacetoxy-8β,13-diisobutanoyloxy-9α-benzoyloxy-4α-hydroxy-β-dihydroagarofuran (1), 1β-picolinoyloxy-2β,6α-diacetoxy-8β,13-diisobutanoyloxy-9α-furanoyloxy-4α-hydroxy-β-dihydroagarofuran (2), and 1β,6α-diacetoxy-2β-nicotinoyloxy-8β,13-diisobutanoyloxy-9α-benzoyloxy-4α-hydroxy-β-dihydroagarofuran (3) on the basis of spectroscopic methods. Compounds 1-11 were all possessed cytotoxic activities against three human tumor cell lines by MTT assay.

■ A New Synthetic Approach to Azuleno[2,1-b]pyridin-4(1H)-ones

Dao-Lin Wang,* Qing-Tao Cui, Shan-Shan Feng, and Jia-Yi Yu

*Liaoning Key Laboratory of Synthesis and Application of Functional Compound, College of Chemistry & Chemical Engineering, Bohai University, Jinzhou 121001, China

Abstract

3-(Dimethylamino)-2-(2-methoxy-1-ethoxycarbonylazulen-3-oyl)acrylonitrile (4) as new synthons directed to heterocycle-fused azulene was obtained by the condensation of ethyl 1-cyanoacetyl-2-methoxyazulene-3-carboxylate (3) and N,N-dimethylformamide dimethyl acetal (DMFDMA). Reaction of this β–enaminone with primary amines (5) in EtOH at fluxing then affords N-substituted 3-cyano-10-ethoxycarbonylazuleno[2,1-b]-pyridin-4(1H)-one derivatives (6) in good yields by a tandem addition-elimination-SNAr reaction. This reaction provides a new procedure for synthesis of pyridinone-fused azulenes.