HETEROCYCLES

■ Contents

■ Preparation of Selenium-Containing Heterocycles Based on an Intramolecular Cyclization of Selenols and Relatives

Haruki Sashida*

*Faculty of Pharmaceutical Sciences, Hokuriku University, 3-Ho, Kanagawa machi, Kanazawa 920-1181, Japan

Abstract

The preparation of the five- to nine-membered selenium-containing heterocycles using the intramolecular cyclization of selenols and relative compounds is mainly described in this review based on recent advances in our findings. Some reactions and chemical properties of the obtained products are also described.

■ Asymmetric Photocyclization Reactions of N-Acetyl-α-dehydro(1-naphthyl)alaninamides in the Presence of Chiral Amine

Kei Maekawa, Toshiyuki Tanami, Tetsutaro Igarashi, and Tadamitsu Sakurai*

*Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan

Abstract

Irradiation of the title compound having an N’-methyl group in 2-propanol and dichloromethane containing (S)-1-methyl-2-pyrrolidinemethanol at room temperature afforded (R)-3,4-dihydrobenzo[f]quinolinone derivative in enantiomeric excesses (ee’s) of 7 and 30%, respectively. On the other hand, the corresponding (S)-enantiomer was obtained in 21–23% ee’s on room temperature irradiation in the above solvents containing (S)-nicotine which enhanced these ee values up to 34–59% at –78 °C.

■ Synthesis of (-)-Untenospongin C, a C21 Furanoterpene Isolated from the Okinawan Sponge Hippospongia Sp.

Yoshihiro Noda,* Shuji Ugajin, Akihiko Yamanaka, and Natsuki Mamiya

*Department of Materials Chemistry and Engineering, College of Engineering, Nihon University, Tamura-machi, Koriyama, Fukushima, 963-8642, Japan

Abstract

Starting with (R)-(+)-citronellol (5), the first enantioselective synthesis of (-)-untenospongin C (1), a C21 furanoterpene isolated from a marine sponge Hippospongia sp., has been achieved, the present synthesis indicating the absolute configuration of 1 as S.

■ The [2+2] Cycloaddition Reaction of Ethynylated 2H-Cyclohepta[b]furan-2-ones with 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone

Taku Shoji,* Junya Higashi, Shunji Ito, Masafumi Yasunami, and Noboru Morita*

*Department of Chemistry, Faculty of Science, Shinshu University, Asahi, Matsumoto 390-8621, Japan

Abstract

Ethynylated 2H-cyclohepta[b]furan-2-ones reacted with 2,3-dichrolo-5,6-dicyano-1,4-benzoquinone (DDQ) in a formal [2+2] cycloaddition reaction to afford the corresponding DDQ-adducts 10–15 in good yields.

■ Utilization of 2-Halo-1,3,4-thiadiazoles in the Synthesis of 2-Functionalized 1,3,4-Thiadiazole Derivatives

Xi-Cun Wang,* Jin-Ge Luo, Xiao-Mei Ding, and Zheng-Jun Quan

*Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, Gansu 730070, China

Abstract

Novel 2-bromo/iodo-5-aryloxymethyl-1,3,4-thiadiazoles were prepared by the diazotization of 2-amino-1,3,4-thiadiazoles using p-TsOH as acid under the copper-free conditions. 2-Chloro-5-aryloxymethyl-1,3,4-thiadiazoles, which were prepared by traditional diazotization, were treated with various nucleophiles to give a series of 2-substituted-1,3,4-thiadiazole derivatives including 2-methylamino/ethylamino/hydroxylethylamino/hydrazinyl-5-aryloxymethyl-1,3,4-thiadizoles and 6-aryloxymethyl[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles.

■ Efficient One-Pot Synthesis of 2-Alkylquinolines under Solvent-Free Conditions Using Sulfonic Acid Functionalized Ionic Liquid as a Recoverable and Reusable Catalyst

Min Zhang,* Biao Xiong, Ting Wang, Yuqiang Ding,* and Li Wang

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

Abstract

ulfonic acid functionalized ionic liquid (FIL-A) was firstly used as a recoverable and reusable catalyst for the synthesis of 2-alkylquinoline derivatives from simple and readily available alkylaldehydes and arylamines. The method has the advantages of simple experimental procedure, easy recovery and reuse of catalyst, solvent-free and mild reaction conditions, excellent functional group tolerance, etc. which makes it a highly practical and environmentally benign pathway for the synthesis of 2-alkylquinolines.

■ A New Method for Synthesis of 2-Alkoxyadenosine Analogs

Norikazu Sakakibara, Takashi Tsuruta, Masahiro Komatsu, Masatoshi Iwai, and Tokumi Maruyama*

*Faculty of Pharmaceutical Sciences at Kagawa Campus, Tokushima Bunri University, 1314-1 Shido, Sanuki City, Kagawa, 769-2193, Japan

Abstract

O6-Methylguanosine and 2-amino-6-chloropurine riboside derivative were treated with isoamylnitrite in the presence of an appropriate alcohol to give the corresponding 2-alkoxy-6-methoxy (or chloro) purine riboside derivatives.

■ CeCl3·7H2O-Catalyzed Synthesis of Quinoxaline Derivatives in Liquid PEG-400

Fang-Wen Wu, Rei-Sheu Hou,* Huey-Min Wang, Iou-Jiun Kang, and Ling-Ching Chen*

*Department of Cosmetic Science, Chung Hwa University of Medical Technology, Department of Chemistry, National Cheng Kung University, Tainan, 701, Taiwan, R.O.C.

Abstract

A mild and efficient route for the synthesis of quinoxaline derivatives utilizing cerium chloride heptahydrate (CeCl3·7H2O) as a novel catalyst in poly(ethylene glycol) (PEG-400) under mild conditions was described.

■ New Phenylpropanoid-Substituted Flavan-3-ols from the Leaves of Castanopsis sclerophylla

Yong-Lin Huang, Yosuke Matsuo, Takashi Tanaka,* Isao Kouno, Dian-Peng Li, and Gen-ichiro Nonaka

*Faculty of Pharmaceutical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan

Abstract

In the course of a chemotaxonomical study of Chinese Castanopsis species, two previously unknown flavan-3-ols, named sclerophynins A and B, were isolated from the leaves of C. sclerophylla, together with five related known compounds. On the basis of spectroscopic analysis, the new compounds were characterized to be (4S,8R,9S)-4-(3,4-dihydroxyphenyl)-8-(3,4,5-trihydroxyphenyl)-3,4,9,10-tetrahydro-5,9-dihydroxy-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one and (4S,7S,8R)-4,8-bis(3,4-dihydroxyphenyl)-3,4,6,7-tetrahydro-5-glucopyranosyloxy-7-hydroxy-2H,8H-benzo[1,2-b:5,4-b']dipyran-2-one, respectively.

■ The Glassy Mesomorphism of Unsymmetrical Bipedal Liquid Crystals Derived from Tetrathiafulvalene and Cholesterol

Ningjuan Zheng, Han Wang, Ruibin Hou, and Bingzhu Yin*

*Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules, Ministry of Education, Yanbian University, Yanji 133002, China

Abstract

1,3-dithiole-2-ones attached two cholesteryl through two ω-thioalkanoyloxy spacer of varying length were easily transformed to the appropriate TTF-based unsymmetrical bipedal by cross-coupling reaction in net triethyl phosphite. All of tetrathiafulvalene-based bipedals exhibit mesogenic phases in a wide temperature region, no crystallization but vitrifying to form glassy mesogens during cooling from the isotropic melt.

■ Synthesis of Hetarenoindanone Based on Selenium Dioxide-Promoted Direct Intramolecular Cyclization

Youlai Zhang, Hiroki Tanimoto, Yasuhiro Nishiyama, Tsumoru Morimoto, and Kiyomi Kakiuchi*

*Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan

Abstract

An alternative and simple method to prepare hetarenoindanone via intramolecular cyclization has been studied. This reaction represents the first example of an intramolecular Friedel-Crafts reaction-oxidation cascade promoted by selenium dioxide by way of Riley allylic oxidation.

■ Convenient Synthesis of Aminopyridinecarboxylic Acids

Iwao Okamoto,* Masayuki Terashima, Rempei Yoshioka, Tomonori Muramatsu, Satomi Kojima, Haruka Inoue, Mio Takahashi, Nobuyoshi Morita, and Osamu Tamura

*Showa Pharmaceutical University, 3-3165, Higashi-tamagawagakuen, Machida, Tokyo 194-8543, Japan

Abstract

6-(Alkylamino)pyridine-2-carboxylic acids and 5-(alkylamino)pyridine-3-carboxylic acids were conveniently synthesized from dibromopyridine in satisfactory yields.

■ Synthesis and Alkylation of Spiro-2-oxazolines Containing Fused 3,4-Dihydropyrazin-2(1H)-ones

Irena Mušič and Bojan Verček*

*Department of Organic Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, P.O. Box 537, SI-1000 Ljubljana, Slovenia

Abstract

Spiro-2-oxazolines containing 3,4-dihydroquinoxalin-2(1H)-one, 3,4-dihydrobenzoquinoxalin-2(1H)-one, 1,2-dihydropyrido[2,3-b]pyrazin-3(4H)- one or 5,6-dihydropteridin-7(8H)-one moiety were prepared by heating of aromatic or heteroaromatic diamines with 2-benzoylamino-3-chloropropenoic acid in the presence of triethylamine. Treatment of spiro-2-oxazolines with MeI or EtBr using Bu4NHSO4 and K2CO3 introduced the methyl or ethyl group on the lactam nitrogen atom.

■ Three New Triterpenoids from Pulsatilla chinensis (Bunge) Regel and Their Cytotoxic Activities

Zhan Shu, Zhong Chen, Xiu-juan Ding, Bing-qian Lu, Chen-jiao Ji, Qiong-ming Xu,* Xiao-ran Li, and Shi-lin Yang

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

Abstract

Three new triterpenoids, pulsatilla triterpenic acids A - C (1-3) were isolated from the roots of Pulsatilla chinensis (Bunge) Regel, and their structures were established on the basis of their spectral data. The three new compounds showed some cytotoxic activities by MTT assay.

■ Synthesis of Furo[2,3-b]pyridine

Meng-Yang Chang* and Hang-Yi Tai

*Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan, R.O.C.

Abstract

Two synthetic routes toward furo[2,3-b]pyridine (1) starting with the known β,γ-unsaturated ester (3) are described.

■ Two New Benzofuranylpropanoids from Nicotiana tabacum and Their Anti-Tobacco Mosaic Virus Activities

Jianlin Tan, Zhangyu Chen, Guangyu Yang, Mingming Miao, Yongkuan Chen,* and Tianfei Li*

*Key Laboratory of Tobacco Chemistry of Yunnan Province, Yunnan Academy of Tobacco Science, Kunming 650106, China

Abstract

Two new benzofuranylpropanoids, nicotfurans A and B (1 - 2), were isolated from the roots and stems of Nicotiana tabacum. Their structures were elucidated by spectroscopic methods, including extensive 1D- and 2D- NMR techniques. Compounds 1 - 2 were tested for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compounds 1 - 2 have high anti-TMV activities.