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. 8, 2008
Published online: 29th February, 2008
■ Enamines as Precursors to Polyfunctional Heteroaromatic Compounds; a Decade of Development
Sayed M. Riyadh,* Ismail A. Abdelhamid, Hamad M. Al-Matar, Noha M. Hilmy, and Mohamed H. Elnagdi
*Department of Chemistry, Faculty of Science, Cairo University, Giza-12613- Egypt
Abstract
Recent synthesis and utilization of enamines as precursors for heterocyclic and carbocyclic compounds are reviewed. Two general synthetic routes for preparation of enamines based on condensation and addition reactions. Enamines and azaenamines can be used as building blocks for carbocyclic, five- and six-membered heterocyclic as well as fused heterocyclic compounds.
Published online: 17th April, 2008
■ A Facile One-Pot Synthesis of Benzimidazoles from 2-Nitroanilines by Reductive Cyclization
Zheng Liu, Haihong Li, Qingjie Zhao, and Jingshan Shen
*Shanghai Institute of Materia Medica, The Chinese Academy of Sciences, 319 Yue-Yang Raod, Shanghai 200031, China
Abstract
A facile one-pot process to prepare benzimidazole derivatives is described. Reductive cyclization of a serial of 2-nitroanilines with orthoesters in the presence of Pd/C in methanol at room temperature, which is promoted by a catalytic amount of acetic acid, affords the corresponding benzimidazole derivatives in high yields.
Published online: 1st April, 2008
■ Solvent-Free Microwave Synthesis of 3-(4-Benzo[b]thiophene-2-carbonyl)-1-piperazinyl-1-benzo[b]thiophen-2-yl-1-propanones. New Hetero Bis-Ligands with Potential 5-HT1A Serotonergic Activity
Hernán Pessoa-Mahana,* Johann Kosche C., Nadia Ron H., Gonzalo Recabarren-Gajardo, Claudio Saitz B., Ramiro Araya-Maturana, and C. David Pessoa-Mahana
*Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Casilla 233, Santiago 1, Chile
Abstract
A novel series of 2-benzothiophenealkylpiperazine derivatives 11(a-d) with potential affinity at 5-HT1A serotonine receptors have been synthesized via solvent-free, microwave-promoted Michael addition of benzo[b]thiophene piperazine derivatives 6(a-c) to substituted benzo[b]thiophen-2-yl propenones 10(b,c).
Published online: 1st April, 2008
■ Selenomaltol — Synthesis, Spectroscopy and Theoretical Calculations
Waldemar Tejchman,* Krzysztof Zborowski, Wieslaw Lasocha, and Leonard M. Proniewicz
*Department of Chemistry, Pedagogical University, Podchorazych St. 2, PL-30084 Kraków, Poland
Abstract
Synthesis and structure of the seleno derivative of maltol (selenomaltol) is described. Structural and energetical properties of possible selenomaltol structures have been calculated at the B1LYP/6-311++G(d,p) level. The lowest energies are always predicted for the keto-enol tautomer. To verify obtained results several standard experimental methods, namely: elemental analysis, mass spectrometry, infrared and NMR spectroscopies and X-ray crystallography have been used. Investigation of IR and NMR spectra clearly indicate that the oxygen atom of exocyclic keto group on maltol was replaced by selenium. Experimental crystallographic results support this conclusion.
Published online: 8th April, 2008
■ Synthesis of Acridine Analogues as Intercalating Crosslinkers and Evaluation of Their Potential Anticancer Properties
Toshinori Higashi, Maki Sakamoto, and Masataka Mochizuki*
*Faculty of Pharmacy, Keio University, 1-5-30, Shiba-koen, Minato-ku, Tokyo 105-8512, Japan
Abstract
We synthesized 4,5-bis(halomethyl)acridines, which contain an acridine skeleton for DNA intercalation and two halomethyl groups for DNA crosslinking. 4,5-Bis(bromomethyl)acridine and 4,5-bis(chloromethyl)acridine intercalated in DNA and mediated interstrand DNA crosslinking. Both compounds were cytotoxic to CCRF-HSB-2 cells, a human T cell leukemia cell line. Molecular modeling of 4,5-bis(bromomethyl)acridine intercalated in 5’-GC-3’ base pairs of DNA indicated that the bromomethyl group, which mediates alkylation, is in close proximity to N7 of guanine.
Published online: 11th April, 2008
■ Synthesis of New Thiazolo[3,2-a]pyrimidin-5-one Derivatives in Reaction of 3-Allyl-2-thiouracils Cyclization
Renata Studzinska, Marcin Wróblewski, and Marcin Draminski*
*Department of General Chemistry, Nicolaus Copernicus University in Torun, Collegium Medicum in Bydgoszcz, ul. Debowa 3, 85-626 Bydgoszcz, Poland
Abstract
The series of thiazolo[3,2-a]pyrimidin-5-one derivatives in cyclization reaction of 3-allyl-2-thiouracil derivatives with iodine monochloride, and then hydrogen iodide elimination from intermediate reaction product has been obtained. On the basis of the studies of reaction kinetics, the elimination reaction mechanism has been proposed. Moreover, the influence of substituent on the reaction elimination rate has been investigated.
Published online: 21st March, 2008
■ Investigation of the Acid-Mediated Cyclisation of Amide Acetal for the Synthesis of Benzazepinone
Wong Phakhodee, Poolsak Sahakitpichan, Songpon Deechongkit, and Somsak Ruchirawat*
*Laboratory of Medicinal Chemistry, Chulabhorn Research Institute, Vipavadee-Rangsit Road, Laksi, Bangkok 10210, Thailand
Abstract
On treatment with acids, the open-chained amide acetals (1) gave the 7,7 membered ring fused benzazepinones (4) via the bis-cyclisation.
Published online: 8th April, 2008
■ Halolactonization of γ-Acetylenic Acids: Synthesis of Novel Spiroisoindole Halobutyrolactones
Mohamed M. Rammah, Mohamed Othman,* Moncef Msaddek, and Mohamed B. Rammah
*URCOM, Faculty of Sciences and Techniques, University of Le Havre, 25 Rue Philippe Lebon, BP 540, F-76058 Le Havre Cedex, France
Abstract
Acetylenic carboxylic acids are cyclized to spirohalo butyrolactones, in the presence of NBS or NIS and K2CO3. The corresponding 5(E)-haloalkylidene-spirobutyrolactones were isolated in high yields, and this process constitutes an easy and efficient route to analogous structures of natural products of biological interest.
Published online: 17th April, 2008
■ Bioactive Constituents from Chinese Natural Medicines. XXXI. Hepatoprotective Principles from Sinocrassula indica: Structures of Sinocrassosides A8, A9, A10, A11, and A12
Kiyofumi Ninomiya, Toshio Morikawa, Haihui Xie, Hisashi Matsuda, and Masayuki Yoshikawa*
*Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8412, Japan
Abstract
The methanolic extract from the whole plant of Sinocrassula indica (Crassulaceae) was found to show hepatoprotective effect on D-galactosamine-induced cytotoxicity in primary cultured mouse hepatocytes. From the methanolic extract, five new acylated flavonol glycosides, sinocrassosides A8 (1), A9 (2), A10 (3), A11 (4), and A12 (5), were isolated together with 25 compounds. The structures of 1-5 were elucidated on the basis of chemical and physicochemical evidence. Among the isolated compounds, sinocrassosides A1 (6), A2 (7), and B2 (14) were found to show potent hepatoprotective effect.
Published online: 8th April, 2008
■ Effects of Aromatic Substituents of Electrochemically Generated Hypervalent Iodine Oxidant on Oxidation Reactions
Yoshiharu Amano and Shigeru Nishiyama*
*Department of Chemistry, Faculty of Science and Technology, Keio University, Hiyoshi, Kohoku-ku Yokohama 223-8522, Japan
Abstract
Phenolic oxidation of 4-hydroxyphenylpropionic acid (5) with electrochemically generated hypervalent iodine oxidant, was performed using a variety of iodobenzene derivatives. Iodobenzene derivatives carrying electron-deficient aromatic moieties showed oxidant activity comparable to that of bis(2,2,2-trifluoroethoxy)phenyliodine(III) 1, and better than those carrying electron-donating groups with the exception of a methyl group. In our electrochemical procedure, the oxidant from 1-iodo-4-nitrobenzene was obtained as a stable solid, while other oxidants that did not precipitate from the reaction mixture, were used in situ. Conversion of the methoxyamide 7 into the corresponding azaspiro derivative 3 was also performed by the oxidants carrying aromkatic substitutions.
Published online: 28th March, 2008
■ Synthesis of Novel Pyrazolo[5,1-b][1,3]benzothiazoles: A New Pericyclic Pathway
Betül Tekiner-Gulbas, László Filák, Gyöngyvér Ágnes Vaskó, Orsolya Egyed, Ismail Yalçin, Esin Aki-Sener, Zuzsanna Riedl, and György Hajós*
*Institute of Biomolecular Chemistry, Chemical Research Center, Hungarian Academy of Sciences, H-1025 Budpest, Pusztaszeri út 59, P.O. Box 17, Hungary
Abstract
2-Benzylbenzothiazoles were easily N-aminated by tosyl hydroxylamine, and the obtained N-amino salts were reacted with ethyl orthoformate to give new derivatives of the pyrazolo[5,1-b][1,3]benzothiazole ring system. Mechanistic considerations suggest that the ring closure reaction proceeds via deprotonation of the N-amino salt followed by electrocyclization to provide the tricyclic ring system. The procedure opens an easy access to variously substituted derivatives of the target ring system.
Published online: 1st April, 2008
■ New β-Tricarbonyl Compounds: Synthesis, Reactions with Urea and Some Thioureas
Mustafa Saçmaci,* Abdulrezzak Alkan, Serife Saçmaci, Emin Saripinar, and Ertan Sahin
*Department of Chemistry, Faculty of Arts and Sciences, Bozok University, Yozgat 66200, Turkey
Abstract
2,3-Dihydro-4-(4-methoxybenzoyl)-5-(4-methoxyphenyl)furan-2,3-dione 1 reacted with some alkyl carbamates (3a-b) via p,p’-dimethoxy- dibenzoylketene intermediate 2 giving new β-tricarbonyl compounds (4a-b). Then, these compounds were converted into 1,3-oxazine-2,4(3H)-dione 7 with urea and 2-thioxo-2,3-dihydropyrimidin-4(1H)-ones (6a-c) with some thiourea derivatives, respectively. Pyrimidin-4-ones (6a-c) and oxazine 7 were obtained in good yields. The structures and characterizations of new synthesized compounds were established by the 1H and 13C NMR, IR, UV-VIS spectroscopic data, elemental analysis, and X-ray diffraction method.
Published online: 8th April, 2008
■ Aplysinopsin Dimers from a Stony Coral. Tubastraea aurea
Tetsuo Iwagawa,* Miho Miyazaki, Yukiko Yokogawa, Hiroaki Okamura, Munehiro Nakatani, Matsumi Doe, Yoshiki Morimoto, and Kaoru Takemura
*Department of Chemistry and Bioscience, Faculty of Science, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
Abstract
Five novel bis(indole) alkaloids, which were composed of two molecules of aplysinopsin have been isolated from a stony coral, Tubastraea aurea. Their structures were elucidated on the basis of spectroscopic methods.
Published online: 11th April, 2008
■ Chemical Constituents of Ligularia franchetiana Collected in Yunnan Province of China
Motoo Tori,* Yui Tanio, Yasuko Okamoto, Yoshinori Saito, Xun Gong,* Chiaki Kuroda,* and Ryo Hanai*
*Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihamabouji, Yamashiro-machi, Tokushima, 770-8514, Japan
Abstract
Two new ketones, franchetianones A and B, were isolated from the root of Ligularia franchetiana collected in Yunnan province of China and their structures determined based on the spectroscopic analyses.
Published online: 28th March, 2008
■ 2-Pyrazolin-5-ones Bearing a Basic Dialkylaminoalkyl Substituent at the N1-Position: Preparation and NMR Spectroscopic Investigations
Barbara M. T. Wolf, Gernot A. Eller,* and Wolfgang Holzer*
*Department of Drug and Natural Product Synthesis, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
Abstract
2n-5-ones (= tautomers to 5-hydroxypyrazols) bearing dialkylaminoyalkyl substituents at the ring nitrogen atom N-1 are prepared from the corresponding hydrazines and beta-ketoesters. Detailed NMR spectroscopic investigations (1H, 13C, 15N) with the obtained compounds are undertaken and the tautomerism of such pyrazolones in solution is discussed.
Published online: 14th April, 2008
■ Conformationally Constrained Adamantaneoxazolines of Pharmacological Interest
Ioannis Papanastasiou, George B. Foscolos,* Andrew Tsotinis, Judit Oláh, Judit Ovádi, S. Radhika Prathalingam, and John Kelly
*Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Athens, Panepistimiopolis-Zografou, Athens GR-15771, Greece
Abstract
New conformationally constrained adamantane 2-oxazoline building blocks 1-4 were synthesized and their antimicrotubule and antitrypanosomal potency was investigated. Although most of the new compounds affect tubulin polymerization, this does not make a major contribution to trypanocidal activity.