HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Regular Issue
Vol. 75, No. 9, 2008
Published online: 7th March, 2008
■ Palladium(II)-Catalyzed Cyclization via N-Alkylation of an Allyl Alcohol with a Urethane and Its Application to the Syntheses of Natural Products
Hajime Yokoyama and Yoshiro Hirai*
*University of Toyama, Graduate School of Science and Engineering, 3190 Gofuku, Toyama 930-8555, Japan
Abstract
Stereoselective amino-palladation of alkenylamines is one of the most important approaches for the stereoselective construction of N-hetero-alicycles, which form the skeletons of several biologically active natural products and related compounds. We reviewed our work with the utility of palladium(II)-catalyzed cyclization via N-alkylation of an allyl alcohol with a urethane. The syntheses of natural products by using Pd(II)-catalyzed cyclization were also reviewed.
Published online: 11th March, 2008
■ Synthesis and Chemical Transformations of Benzoxazepines
Albert Lévai*
*Department of Organic Chemistry, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary
Abstract
This review describes synthetic procedures for the preparation of all the known benzocondensed derivatives of the 1,2-, 1,3- and 1,4-oxazepines. Examples for the most important chemical transformations of some benzoxazepine groups providing their useful derivatives have also been included. Owing to the huge number of papers in this field, it is not the aim of this review article to list and discuss all the papers published in the chemical literature.
Published online: 15th May, 2008
■ Peroxisome Proliferator-activated Receptor (PPAR) Agonists with 3,4-Dihydro-2H-benzo[e][1,3]oxazine and 2,3,4,5-Tetrahydrobenzo[f][1,4]oxazepine Skeletons: Effects of Cyclization of Linker Moiety on PPAR-Agonistic Activity
Kenji Ohgane, Jyun-ichi Kasuga, Takuji Ohyama, Yuko Hirakawa, Kosuke Morikawa, Makoto Makishima, Yuichi Hashimoto, and Hiroyuki Miyachi*
*Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
Abstract
Conformationally restricted heterocyclic derivatives of KCL ((S)-2-{4-methoxy-3-[4-(trifluoromethyl)benzylcarbamoyl]benzyl}butanoic acid), which exhibit selective PPAR±-agonistic activity, were prepared to examine the significance of the amide bond of KCL. In vitro transactivation assay clearly indicated that introduction of a 2-position fluorine atom enhanced PPARs-agonistic activity as expected, while cyclization of the amide bond caused a drastic decrease of PPARs-agonistic activity.
Published online: 21st April, 2008
■ Facile Entry to Ethyl Tetrahydro-1H-pyrrolizin-7a(5H)-ylacetate: a Versatile Pharmaceutical Intermediate
Claudio Bruno, Alessia Catalano, Giovanni Lentini,* Alessia Carocci, Carlo Franchini, and Vincenzo Tortorella
*Medicinal Chemistry Department - Campus, University of Studies - Faculty of Pharmacy, via E. Orabona n. 4, 70125 Bari, Italy
Abstract
An improved synthesis of ethyl tetrahydro-1H-pyrrolizin- 7a(5H)-ylacetate is reported. This valuable pharmaceutical intermediate was easily obtained from 1,7-diiodo-4-heptanone in 46% yield, thus improving the procedure reported in the literature (23% yield) which starts from 1,7-dichloro-4-heptanone. Moreover, 1,7-diiodo-4-heptanone was obtained as an easily manageable solid, in this being preferable to its 1,7-dichloro isologue, which is a quite unstable oil. The former was synthesized in high overall yield (75%) starting from the commercially available diethyl 4-oxoheptanedioate, thus overtaking the well-known problems related to the use of γ-butyrolactone.
Published online: 21st April, 2008
■ Studies on Enamines and Azaenamines: 2-Oxoarylhydrazonals as C-1 Nucleophiles
Saleh M. Al-Mousawi,* Moustafa Sherief Moustafa, and Mohamed Hilmy Elnagdi
*Department of chemistry, Faculty of Science; University of Kuwait: Safat; 13060: Kuwait
Abstract
2-Oxoarylhydrazonals 1a,b react with aldehydes; piperidine; morpholine and benzotriazole to yield the corresponding Mannich bases 2a,f, and 4. Formaldehyde reacts with 1a,b to yield the hydroxymethylarylhyrazons 5a,b together with bisarylhydrazones 6. The hydroxymethyl derivatives 5a are converted to arylhydrazonal 7 upon oxidation in refluxing nitrobenzene. The reaction of aldehydes and malononitrile with 1a,b in ethanolic solution in presence of chitozan as heterogeneous catalyst afforded 6-amino-1,4-dihydropyridazins 14a,b.
Published online: 24th April, 2008
■ The Behaviour of M+. and [M+H]+ Ions of Some Oxoisoaporphines and Quinolinone Analogs
Giovanni Valitutti, Eduardo Sobarzo-Sánchez, and Pietro Traldi
*CNR-ISTM, Corso Stati Uniti, 4, I35127 Padova, Italy
Abstract
The mass spectrometric behaviour of some oxoisoaporphines and quinolinone analogs has been studied by both electrospray and electron ionization methods. By the former approach, information can be obtained on the decomposition pattern of the compounds under investigation in acidic condition, while by the latter the behaviour related to both cationic and radical character of molecular ion can be put in evidence. The collisional spectra of the protonated molecules indicate that protonation has taken place on both oxygen and nitrogen atoms. This can be justified by the fact that even if the most basic site present in the molecule is surely the N atom, in mass spectrometry conditions the protonation reactions are not governed by thermodynamics only, but kinetic effects can also play a fundamental role. Some exception to the even electron rule have been evidenced, and can be well justified by the high stability of the odd electron fragment ion. In electron ionization conditions fragmentation patterns well related to the original structures are present, allowing the characterization of isomeric compounds by the presence of specific fragmentation routes.
Published online: 24th April, 2008
■ Tungstophosphoric Acid Supported on Titania as an Eco-Friendly, Green and Reusable Catalyst for the Solvent-Free Hantzsch Multi-Component Condensation
Ezzat Rafiee,* Sara Eavani, Solmaz Rashidzadeh, and Mohammad Joshaghani
*Department of Chemistry, Faculty of Science, Razi University, 67149, Kermanshah, Iran
Abstract
Tungstophosphoric acid supported on titania (PW/TiO2), catalyzed three and four component coupling of various β-dicarbonyl compounds, aldehydes and amines under solvent free conditions. Different 4-aryl, N-hydroxy ethyl and N-aryl substituted 1, 4-dihydropyridines and polyhydroquinoline derivatives, have been synthesized with high to excellent yields. Short reaction times, simple work-up, and mild reaction conditions are advantages of this procedure. The catalyst is reusable without loss of activity for five runs.
Published online: 21st April, 2008
■ Synthesis and Characterization of 2,3,5,6-Tetraphenylpyrazine-N, N-Dioxide: New Nitrone Dimer Species
Ali Hashem Essa,* Zeki A. Nasir Al-Shamkhani, Abraham F. Jalbout, and Ali Jameel Hameed
*Department of Chemistry, College of Science, University of Basrah, Basrah, Iraq
Abstract
The synthesis, characterization and physical properties of 2,3,5,6-tetraphenylpyrazine-N,N-dioxide presently are reported. A specific reduction mechanism of an oxime using zinc with NH4Cl to yield hydroxylamine was performed. This was followed by a condensation reaction with sulfuric acid that leads to 2,3,5,6-tetraphenylpyrazine-N,N-dioxide. The product was characterized by means of IR, UV, 1H-NMR and 13C-NMR spectroscopy which were complemented by theoretical computations.
Published online: 8th May, 2008
■ A New Sulfa-Heterocyclic Compounds Containing Aziridine Moiety, 3-Benzyl-2-thia-1,3-diazabicyclo[3.1.0]hexane 2,2-Dioxide and Its Reaction with Nucleophiles
Nawel Khettache, Malika Berredjem, Zine Régaïnia, and Nour-Eddine Aouf*
*LCOA. Bioorganic Chemistry Group. Sciences Faculty, Chemistry Department. Badji Mokhtar, Annaba University. Box.12 Annaba-Algeria
Abstract
New sulfa-heterocyclic containing aziridine moiety derivatives such as 3-benzyl-2-thia-1,3-diazabicyclo[3.1.0]hexane 2,2-dioxide has been obtained starting from 2-benzyl-4-chloromethyl-1,2,5-thiadiazolidine 1,1-dioxide in alkaline conditions. The aziridine moiety was opened by various nucleophiles to give vicinal diamines which used as an intermediate in the preparation of other bicyclic compounds with orthogonal protections such as 2,5-dibenzyl-1,2,5-thiadiazolo[2,3-a]pyrazine 1,1-dioxide in good yield.
Published online: 12th May, 2008
■ The Synthesis and Microbiological Activity of 2-Mercapto-4-(pyrrolidin-1-yl)pyridine-3-carbonitrile Derivatives
Agnieszka Miszke,* Henryk Foks, Anna Kedzia, Ewa Kwapisz, and Zofia Zwolska
*Department of Organic Chemistry, Medical University of Gdansk, Poland
Abstract
Synthesis of 2-mercapto-4-(pyrrolidin-1-yl)pyridine derivatives starting from 2-bromo-4-(pyrrolidin-1-yl)pyridine-3-carbonitrile (1) is described. The desired derivatives of 2-(phenylthio)-4-(pyrrolidin-1-yl)pyridine- 3-carbonitrile were obtained in reaction of 1 with suitable thiophenoles, while reaction with benzyl mercaptan gave a related thiobenzyl derivative. Alternatively, compound 1 was transformed into 2-mercapto-4-(pyrrolidin-1-yl)pyridine- 3-carbonitrile (2). Reaction of 2 with chloroacetic acid or chloroacetone derivatives gave related products of mercapto group substitution. The latter compounds could be cyclized in Thorpe-Ziegler reaction to related 3-amino-4- (pyrrolidin-1-yl)thieno[2,3-b]pyridine derivatives. Reaction of 2 with sodium hydroxylamino-O-sulphonate gave the related aminosulfanyl derivative. Selected product were screened for bacteriostatic and antituberculosis activity, and some of them exhibited a significant activity.
Published online: 8th May, 2008
■ Synthesis of New 3-Nitroimidazo[1,2-a]pyridine Derivatives by SRN1 Reactions
Rémi Szabo, Maxime D. Crozet, and Patrice Vanelle*
*Universities of Aix-Marseille I, II, and III - CNRS, UMR 6264: Provence Chemistry Laboratory, Radical Pharmaco-Chemistry Team (LPCR), Faculty of Pharmacy, 27 Boulevard Jean Moulin, 13385 Marseille cedex 05, France
Abstract
6,8-Dibromo-2-chloromethyl-3-nitroimidazo[1,2-a]pyridine was prepared and reacted under experimental conditions of SRN1 reactions with different carbon and sulfur centered nucleophiles to determine the relative reactivities of the different types of electrophile halides. Depending on the nucleophile nature, the chloromethyl group and bromine atom in 8-position were found to be reacting under these experimental conditions. An SRN1 reaction on the pyridine part of the imidazo[1,2-a]pyridine is described for the first time.
Published online: 28th April, 2008
■ The Regioselective Synthesis of 2H-Pyrido[2,3-b]pyrrolo[2,3-e]pyrazin-2-one
Krzysztof Jamrozy, Katarzyna Szymoniak, and Katarzyna Ostrowska*
*Department of Organic Chemistry, Jagiellonian University, R. Ingardena 3, PL-30060 Kraków, Poland
Abstract
The regioselective reaction of 1-aryl-4-(phenylhydroxymethylidene)- pyrrolidine-2,3,5-triones 1 with 2,3-diaminopyridine in boiling glacial AcOH in the presence of TsOH led to the formation of new 2H-pyrido[2,3-b]pyrrolo[2,3-e]pyrazin-2-ones. The structure of this fused heterocyclic system was confirmed by IR, 1D and 2D NMR experiments.
Published online: 21st April, 2008
■ Flavisiamines A-D, New Indole Alkaloids from Kopsia flavida
Mitsuhiro Sekiguchi, Yusuke Hirasawa, Kazumasa Zaima, Teh Chin Hoe, Kit-Lam Chan, and Hiroshi Morita*
*Faculty of Pharmaceutical Sciences, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
Abstract
Four new methyl chanofruticosinate-type alkaloids, flavisiamines A (1) ~ D (4) have been isolated from Kopsia flavida (Apocynaceae) and their structures were elucidated by NMR spectral analysis using 2D techniques.
Published online: 28th April, 2008
■ An Expedient Method to the Synthesis of N-Substituted 1H-Isoindole-1,3(2H)-diones
Farzad Nikpour* and Baran Mohammadi Mogaddam
*Department of Chemistry, Faculty of Sciences, University of Kurdistan, P.O. Box 66315-416, Sanandaj, Iran
Abstract
The synthesis of N-substituted 1H-isoindole-1,3-(2H)-diones is described from the reaction of cyclic anhydrides with Schiff bases as suitable replacing substrates instead of the corresponding amines.
Published online: 24th April, 2008
■ A Clean Synthesis of 3,3-Bis(5-Amino-1H-pyrazol-4-yl)-indolin-2-one Derivatives
Somayeh Ahadi, Ghazaleh Imani Shakibaei, Peiman Mirzaei, and Ayoob Bazgir*
*Department of Chemistry, Faculty of Science, Shahid Beheshti University, Tehran 1983963113, Iran
Abstract
A clean and efficient method has been reported for the condensation of 1,3-diphenyl-1H-pyrazol-5-amine with isatines in aqueous media to afford the corresponding 3,3-bis(5-amino-1H-pyrazol-4-yl)indolin-2-one derivatives in good yields.
Published online: 28th April, 2008
■ Synthesis of 1,4-Dihydro-2H-3,1-benzoxazin-2-ones by Hydriodic Acid Mediated Cyclization of tert-Butyl 2-Vinylphenylcarbamates
Kazuhiro Kobayashi,* Shuhei Fukamachi, and Hisatoshi Konishi
*Department of Materials Science, Faculty of Engineering, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan
Abstract
A two-step facile synthesis of 4,4-disubstituted 1,4-dihydro-2H-3,1- benzoxazin-2-ones starting from ±-substituted 2-aminostyrenes is described. The method involves the hydriodic acid mediated cyclization of t-butyl 2-vinylphenylcarbamate derivatives, which could be easily prepared by N-t-butoxycarbonylation of ±-substituted 2-aminostyrene derivatives, under mild conditions.