HETEROCYCLES

■ Contents

■ Pyrrolo[2,1-b]thiazoles

Anton V. Tverdokhlebov

*Enamine Ltd., Alexandra Matrosova str. 23, 01103, Kiev, Ukraine

Abstract

Synthesis and properties of pyrrolo[2,1-b]thiazoles have been reviewed. The literature from 1940 to 2005 is covered. Bibliography comprises 136 references.

■ Synthesis and Electron-Transporting Ability of 3,6-Diaryl-4,5-diazafluorenes Modified Using Direct Arylation

Katsuhiko Ono,* Kyohei Nagano, Michitaka Suto, and Katsuhiro Saito

*Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan

Abstract

A modification of 4,5-diazafluorene by using direct arylation was performed in order to synthesize a new type of electron-transporting materials in the study of organic electroluminescent (EL) devices. The title compounds possessed high glass transition temperatures over 100 °C. The phosphorescent EL performance was improved by the increasing electron-transporting ability arising from the extension of the π-electron system.

■ Aluminum Dodecatungstophosphate Promoted Synthesis of 1,5-Benzodiazepine Derivatives under Solvent-Free Conditions

Razieh Fazaeli,* Hamid Aliyan,* and Shahram Tangestaninejad

*Department of Chemistry, Islamic Azad University, Shahreza branch, 86145-311, Iran

Abstract

Solid heteropoly acids (AlTP and AlMP) are easily used as efficient catalyst for conversion of o-phenylenediamines and ketones to their corresponding 2,3-dihydro-1H-1,5-benzodiazepines at room temperature under solvent-free conditions. The method is an easy, rapid, and high yielding reaction for the synthesis of 1,5-benzodiazepine derivatives and is applicable to both cyclic or acyclic ketones without significant difference.

■ Regio- and Stereoselective Head-to-Head Photo[2+2]cycloaddition of 3-(1-Methyl-2-phenylsulfanyl-1H-imidazol-5-yl)propenoates

Shunsaku Ohta,* Abdul Khadeer, Akiko Kakuno, Ikuo Kawasaki, and Masayuki Yamashita

*Department of Functional Molecular Chemistry, 21st Century COE program, Kyoto Pharmaceutical University, Misasagi, Yamashinaku, Kyoto 607-8414, Japan

Abstract

Head-to-head photo[2+2]cycloaddition of 1,ω-di[3-(1-methyl- 2-phenylsulfanyl-1H-imidazol-5-yl)propenoyloxy]alkylenes smoothly proceeded under irradiation of a high-pressure mercury lamp to give cyclobutane compounds regio- and stereoselectively. The stereochemistry of these cyclobutanes was determined as β-form.

■ Pictet-Spengler Synthesis of Some New Indolo[2,3-c]quinolines

Saida A. Dabaien, Mustafa M. El-Abadelah,* Salim F. Haddad, and Helmut Duddeck

*Chemistry Department, Faculty of Science, University of Jordan, Amman, Jordan

Abstract

A synthesis of some new indolo[2,3-c]quinolines (16a-c) is achieved by cyclocondensation of 3-[2-amino-(4-trifluoromethyl)phenyl]indole (15) with the appropriate aldehyde under Pictet-Spengler reaction conditions. Regio-selective cyclization occurred at the usual indolic C-2 position as evidenced from NMR spectral data of 16a-c, and confirmed by X-ray crystal structure determination for 16c.

■ Copper(I) Iodide-Catalyzed Coupling Reaction of Haloindoles with α-Amino Acids

Masayuki Kurokawa, Waka Nakanishi, and Tsutomu Ishikawa*

*Graduate School of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan

Abstract

Copper (I) iodide-catalyzed amination of haloindoles with amino acids using a combination of Cs₂CO₃ in DMSO was explored. Amino acid derivatives with indole skeleton were smoothly afforded in moderate yields.

■ A Stepwise Synthesis of Bi-1,2,5-thiadiazole Compounds Using S₄N₄·SbCl₅ Complex

Kil-Joong Kim* and Kyongtae Kim

*Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA

Abstract

Bi-1,2,5-thiadiazole compounds (7) were synthesized step by step by reaction of 1-(4-substituted-3-1,2,5-thiadiazolyl)alkanone oximes (6) with tetrasulfur tetranitride antimony pentachloride complex (S₄N₄·SbCl₅, 1) in toluene at 100 °C for 0.5 h in 28 - 80% yields.

■ Synthesis of Vinca Alkaloids and Related Compounds. Part 107. An Efficient Convergent Synthetic Pathway to Build up the Ibophyllidine Skeleton III. Total Synthesis of (±)-Ibophyllidine and (±)-20-Epiibophyllidine

Flórián Tóth, György Kalaus,* István Greiner, Mária Kajtár-Peredy, Ágnes Gömöry, László Hazai, and Csaba Szántay

*Department for Organic Chemistry, Research Group for Alkaloid Chemistry of the Hungarian Academy of Sciences, Budapest University of Technology and Economics, Gellért tér 4, H-1521 Budapest, Hungary

Abstract

Starting from 5-ethyldihydrofuran-2(3H)-one (9) we prepared aldehydes (6 and 7) which, in a [4+2] cycloaddition reactions with the tryptamine derivative (8) gave, as a final step, compounds (13 and 22) having D-seco-pseudoaspidospermane skeleton. We synthesized (±)-20-epiibophyllidine (4) via the benzoate ester (15) or the mesylate (17) of alcohol (14) which had been obtained from 13, while the catalytic hydrogenation of 22 led to (±)-ibophyllidine (3) via full epimerization, cyclization and reduction steps in one operation.

■ A Novel Divergent Synthesis of ortho-Hydroxy-E and -F Oxide-Bridged 5-Phenylmorphans

Josef Zezula, Arthur E. Jacobson, and Kenner C. Rice*

*Drug Design and Synthesis Section, Chemical Biology Research Branch, Building 8, Room B1-23, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, 20892-0815, USA

Abstract

5-(2-Bromo-3-methoxyphenyl)-2-methyl-2-azabicyclo[3.3.1]nonan-9-one was prepared in six steps from a known acetonitrile. Stereoselective reduction of the ketone furnished the corresponding β- or α-alcohols and their deprotonation, intramolecular cyclization, and demethylation gave ortho-hydroxy-e and -f oxide-bridged 5-phenylmorphans, respectively. This new synthetic route has the desired oxygenation pattern in place, eliminating the problematic diazonium reactions used in former syntheses.

■ Synthesis of Mexiletine Analogues from Non-Activated Aziridines

Truls Ingebrigtsen and Tore Lejon*

*Faculty of Science, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway

Abstract

A general method for the synthesis of mexiletine analogues by nucleophilic ring opening of non-activated racemic aziridines has been developed (Scheme 1). Structural variation is introduced by employing different nucleophiles or by altering the substitution on the aziridine ring.

■ Mechanism of Criss-Cross Reaction of Aromatic Glyoxalimines with Potassium Cyanate and Thiocyanate

Jirí Hanusek,* Jirí Verner, and Milan Potácek

*University of Pardubice, Department of Organic Chemistry, Nám. Cs. legií 565, CZ-532 10 Pardubice, Czech Republic

Abstract

Aromatic 1,4-diazabuta-1,3-dienes (glyoxalimines) react with potassium cyanate and thiocyanate in ethereal acetic acid to give the corresponding4-acetoxy-5-(4-substituted phenylamino)-3-(4-substituted phenyl)- imidazolidin-2-ones and perhydroimidazo[4,5-d]imidazol-2,5-dithiones, respectively. In order to learn more about the reaction mechanism, kinetic measurements have been carried out. It was found that the reaction involves a direct nucleophilic addition of thiocyanate anion to 1,4-diazabuta-1,3-diene, whereas the less nucleophilic cyanate anion requires acid catalysis.

■ Chemoselective Oxidation of 6-Hydroxyalkylpteridine and Its Application to Synthesis of 6-Acyl-7,8-dihydropteridine

Sudhir S. Landge, Kazunari Kudoh, Yuri Yamada, and Shizuaki Murata*

*Graduate School of Environmental Studies, Nagoya University, Chikusa Nagoya 464-8601 Japan

Abstract

Alcohol-selective oxidation of 6-1’-hydroxyalkylpteridines catalyzed by ruthenium (IV), RuO₄^-, gives 6-acylpteridines in high yields. Partial reduction of the products affords 6-acyl-7,8-dihydropteridine derivatives, such as a lipophilic derivative of sepiapterin, deoxysepiapterin, and sepiapterin-C.

■ Bismuth Nitrate-Catalyzed Michael Reactions of Indoles in Water

Bimal K. Banik,* Isabella Garcia, and Frances R. Morales

*Department of Chemistry, The University of Texas-Pan American, 1201 West University Drive, Edinburg, Texas, U.S.A.

Abstract

A remarkable and simple bismuth nitrate-catalyzed Michael reaction of indoles with 1,2-unsaturated ketones in water has been developed to reduce the complications that characterize the current standard conditions.

■ An Efficient Two-Step Synthesis of 4-Methyl-1,2,3,5,6,10b-hexahydropyrimido[5,4-c]quinoline-2,5-diones via Biginelli Reaction

Lhassane Ismaili, Sophie Ubaldi, Jean-Francois Robert, Alain Xicluna, and Bernard Refouvelet*

*Equipe Sciences séparatives et Biopharmaceutique (2SB), Laboratory of medicinal chemistry, Faculty of Pharmacy, 4, place Saint Jacques - 25030 Besançon Cedex, France

Abstract

An efficient two-step synthesis of 4-methyl-1,2,3,5,6,10b-hexahydropyrimido[5,4-c]quinoline-2,5-diones is presented. It consists of the reactions of appropriate aldehyde, urea and ethyl acetoacetate according to Biginelli reaction, followed by cyclisation with ammonia.

■ Synthesis of Indolizidine 167B

Meng-Yang Chang,* Tsun-Cheng Wu, and Ya-Jung Ko

*Department of Applied Chemistry, National University of Kaohsiung, Kaohsiung 811, Taiwan, R.O.C.

Abstract

A new synthesis of indolizidine 167B has been achieved from trans-(2S,4R)-4-hydroxyproline via ring-closing metathesis as the key step.

■ Four New Lignans from Kadsura heteroclita

Li-jia Xu, Yong Peng, Si-bao Chen,* Shi-lin Chen, and Pei-gen Xiao*

*Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100094, P. R. China

Abstract

Four new lignans, heteroclitins I-L (1-4), were isolated from the stems of Kadsura heteroclita (Roxb.) Craib. Their chemical structures were elucidated on the basis of 1D and 2D NMR.