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. 68, No. 9, 2006
Published online: 18th July, 2006
■ Endo-Selective Asymmetric Inverse Electron-Demand 1,3-Dipolar Cycloaddition Reaction of Nitrones
Tomoko Ashizawa, Natsuki Ohtsuki, Tomoyuki Miura, Makoto Ohya, Takaomi Shinozaki, Taketo Ikeno, and Tohru Yamada*
*Department of Chemistry, Faculty of Science and Technology, Keio University, Hiyoshi, Kohoku-ku Yokohama 223-8522, Japan
Abstract
In the presence of a catalytic amount of the optically active cobalt(III) hexafluoroantimonate, the inverse electron-demand 1,3-dipolar cycloaddition reaction of dihydrofuran with nitrones bearing an electron-withdrawing group effectively proceeded to afford the corresponding adducts with excellent endo-selectivity.
Published online: 28th July, 2006
■ Regioselective N- and O-Alkylation of 3H-[1,2,3]triazolo[4,5-d]pyrimidine-5,7(4H,6H)-diones (8-Azaxanthines) and Transformation of 3-Alkyl Derivatives into 1-Alkyl Isomers
Tomohisa Nagamatsu* and Rafiqul Islam
*Faculty of Pharmaceutical Science, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
Abstract
The alkylation on the pyrimidine ring of 3-methyl-3H-[1,2,3]triazolo[4,5-d]pyrimidine-5,7(4H,6H)-diones (1) with an equimolecular amount of alkylating agent in the presence of anhydrous potassium carbonate in aprotic solvents under heating took place only at the 4-position. The similar alkylation on the triazole ring of 6-methyl-1H-[1,2,3]triazolo[4,5-d]pyrimidine-5,7(4H,6H)-diones (4) with an equivalent alkylating reagent happened simultaneously at the 1- and 2-positions with the priority at the 2-position. On the other hand, the alkylation of 3,6-disubstituted derivatives (12a-d) at room temperature led to the 5-O-alkylation (14a-e) accompanied with the 4-N-alkylation (3a, 13a-d), but at high temperature only the 4-N-alkylation occurred. The 3,4,6-tri-substituted derivatives (3a, 13d) underwent transformation with excess alkylating agents at high temperature leading to the formation of 1,4,6-trisubstituted derivatives (7, 15) with elimination of the 3-substituent in the same manner as xanthine.
Published online: 4th July, 2006
■ An Efficient Method for the Synthesis of 3-Mercapto-1-(1,3-thiazolin-2-yl)azetidine Useful for the Pendant Moiety of Oral Carbapenem, L-084
Takeshi Isoda,* Satoshi Tamai, Toshio Kumagai, and Yoshimitsu Nagao*
*Medical Research Laboratories, Wyeth K. K., 1-6-34, Kashiwa-cho, Shiki-shi, Saitama 353-8511, Japan
Abstract
An efficient method for the synthesis of 3-mercapto-1-(1,3-thiazolin-2-yl)azetidine (1) is described. This thiol synthesis was achieved in 3 steps from readily available 3-methanesulfonyloxyazetidine via key intermediates, Bunte salts (3 and 5). The final step was enabled to proceed under mild conditions using the benzylthiol-mediated cleavage of the S-S bond in the Bunte salt (3).
Published online: 25th July, 2006
■ 4-Acyl-5-hydroxy-1-phenyl-3-trifluoromethylpyrazoles: Synthesis and NMR Spectral Investigations
Sabine Bieringer and Wolfgang Holzer*
*Department of Drug Synthesis, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
Abstract
The title compounds were prepared by reaction of 1-phenyl-3-trifluoromethyl-1H-pyrazol-5-ol with trimethyl orthoacetate, triethyl orthopropionate and triethyl orthobenzoate, respectively, followed by hydrolytic cleavage of the primarily formed condensation products. Detailed NMR spectroscopic investigations with the obtained products are presented, revealing the title compounds to be present as 5-hydroxypyrazoles stabilized by an intramolecular hydrogen bond in CDCl3 solution.
Published online: 29th June, 2006
■ Efficient Michael Addition of Indoles Using Bismuthyl Perchlorate as Catalyst
Iraj Mohammadpoor-Baltork,* Hamid Reza Memarian,* Ahmad Reza Khosropour, and Kobra Nikoofar
*Department of Chemistry, Faculty of Science, Isfahan University, Isfahan University, Isfahan 81746-73441, Iran
Abstract
An efficient method for Michael addition of indoles has been developed using bismuthyl perchlorate (BiOClO4·xH2O) as catalyst. The reaction proceeds to give 3-substituted indoles excellently stirring indoles and Michael acceptors in acetonitrile in the presence of the catalyst at room temperature or in much shorter reaction times under sonication at ambient temperature.
Published online: 30th June, 2006
■ 3-Benzoyl-4-hydroxyisochromen-1-one Derivatives, Their Synthesis and Synthetic Application
Pavel Hradil,* Radek Melnicky, Martin Grepl, Kamil Koristek, Jan Hlavac, and Valerio Bertolasi
*Department of Organic Chemistry, Palacky University, Trida Svobody 8 ,77146 Olomouc, Czech Republic
Abstract
3-Benzoyl-1,4-isochromandione derivatives were prepared by cyclization of phenacyl phthalates (2). The cyclization was done in the presence of N-methylpyrrolidone and potassium hydroxide. These compounds served as intermediates for the synthesis of more complicated isocoumarine derivatives. A Wittig reaction with (carbethoxymethylene)triphenyl phosphorane was conducted in a microwave reactor and resulted in the formation of substituted 4-phenylpyrano[3,2-c]isochromene-2,6-dione.
Published online: 30th June, 2006
■ Highly Stereoselective Formation of 1,3-Dioxolanes by Photocatalytic Ring Opening Reactions of α-Epoxyketones in Acetone Solution Using 1-Benzyl-2,4,6-triphenylpyridinium Tetrafluoroborate (NBTPT)
Hamid Reza Memarian,* Ali Saffar-Teluri, and Mohammad Kazem Amini
*Department of Chemistry, Faculty of Science, Isfahan University, Isfahan 81746-73441, Iran
Abstract
Highly stereoselective formation of 1,3-dioxolanes has been observed on photoinduced electron transfer ring opening of α-epoxyketones by 1-benzyl-2,4,6-triphenylpyridinium tetrafluoroborate (NBTPT) in acetone solution. The presence of various substituents on the donor molecule has not affected the rate of the ring opening and also stereoselectivity of the reaction too much. Stepwise addition of the photocatalyst leads to decreasing of irradiation time and increasing of the yield of products. Photoinduced electron transfer deoxygenation and isomerization of some α-epoxyketones has also been observed. Cyclic voltammetric study of the photocatalyst shows a greater tendency of NBTPT for accepting an electron in the excited state.
Published online: 21st July, 2006
■ Synthesis of 4-Trifluoromethylpyrimido[4,5-c]pyridazine-5,7-diones from Uracils
Masahiko Takahashi,* Yoshinobu Ogawa, and Kazuhiro Inoue
*Department of Industrial Chemistry, Faculty of Engineering, Ibaraki University, Hitachi, Ibaraki 316-8511, Japan
Abstract
The reaction of 6-hydrazinouracils (1) with 3-aryl-1,1,1-trifluoropropane-2,3-dione monohydrates (2) in refluxing ethanol in the presence of p-toluenesulfonic acid gave regioselectively 3-aryl-4-trifluoromethyl-5,6,7,8-tetrahydropyrimido[4,5-c]pyridazine-5,7-diones (4a-e) in moderate yields. The location of a trifluoromethyl group at the C4 position was elucidated on the basis of the chemical transformation of the derivatives.
Published online: 4th July, 2006
■ A Novel Two Step Synthesis of 3,4-Dihydro-4-oxo-5H-pyrano[2,3-d]pyrimidines
Jitender M. Khurana,* Arpita Agrawal, and Gagan Kukreja
*Department of Chemistry, University of Delhi, Delhi-110 007, India
Abstract
A novel two step synthesis of 5,7-diaryl-3,4-dihydro-4-oxo-5H-pyrano[2,3-d]pyrimidines has been reported based on condensation of 2-thiobarbiturates with chalcones followed by reductive desulfurization of 5,7-diaryl-1,2,3,4-tetrahydro-4-oxo-2-thioxo-5H-pyrano[2,3-d]pyrimidines with nickel boride.
Published online: 11th July, 2006
■ Bromination of Dimethyl 1-Substituted Indole-2,3-dicarboxylates
Yasuyoshi Miki,* Misako Umemoto, Mai Nakamura, Hajime Hibino, Noriko Ohkita, Akiko Kato, and Yoshiyuki Aoki
*Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1, Kowakae, Higashi-Osaka 577-8502, Japan
Abstract
Treatment of dimethyl indole-2,3-dicarboxylate with pyridinium hydrobromide perbromide or bromine in the presence of Lewis acid gave dimethyl 5 bromoindole-2,3-dicarboxylate as the sole product. In a similar manner, dimethyl 1-benzyl- and 1-benzenesulfonyl-indole-2,3-dicarboxylates provided a mixture of the corresponding 5 bromoindole and 6-bromoindole derivatives. However, methyl 1-trifluoromethanesulfonylindole-2,3-dicarboxylate gave methyl 6-bromo-1-trifluoromethanesulfonylindole-2,3-dicarboxylate as a major product.
Published online: 28th July, 2006
■ Accelerated Synthesis of Novel 1,2,4-Triazolo[3,4-b][1,3,4]thiadiazepines under Microwave Irradiation
Ahmet Çetin
*Department of Chemistry, Graduate School of Natural and Applied Sciences, Firat University, 23119 Elazig, Turkey
Abstract
A convenient and efficient one step, base catalyzed synthesis of 3,5-disubstituted-4-amino-1,2,4-triazoles by condensation of thiol and hydrazide is presented. An environmentally benign and economic synthesis for the title compounds is described from readily accessible substituted 4-amino-5-mercapto-1,2,4-triazoles and substituted chalcones on basic alumina that are accelerated by exposure to microwave irradiation.
Published online: 18th July, 2006
■ CuTC Mediated Coupling of 6,7-Disubstituted Benzothiazoles
Livio Racanè, Vesna Tralic-Kulenovic,* Gordana Pavlovic, and Grace Karminski-Zamola
*Department of Applied Chemistry, Faculty of Textile Technology, University of Zagreb, Prilaz baruna Filipovica 30, 10000 Zagreb, Croatia
Abstract
A synthesis of the halogeno derivatives of substituted benzothiazoles (2-6) is described, and dimerization using copper in different oxidation states is examined. Dimerization of iododerivatives (2) and (4) by copper(I) thiophen-2-carboxylate (CuTC) mediated coupling afforded the corresponding o,o’-disubstituted bibenzothiazoles (7) and (8) in excellent yield.
Published online: 29th June, 2006
■ Two New Macrocyclic Compounds from the Stems of Clematis armandii
Lihua Yan, Shilin Yang, Zhongmei Zou, Xiuzhen Luo, and Lizhen Xu*
*Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 151, North Malianwa Rd., XibeiWang, Hai-Dian District, Beijing 100094, China
Abstract
Phytochemical investigation of Clematis armandii (Ranunculaceae) has resulted in the isolation of two new macrocyclic compounds named clemoarmanosides A (1) and B (2), along with two known macrocyclic compounds berchemolide (3) and clemochinenoside B (4). The structures of 1 and 2 were elucidated on the basis of spectroscopic data and chemical methods. In addition, several 13C-NMR data of 4 were amended by 2D-NMR spectra analysis in this paper.
Published online: 29th June, 2006
■ Synthesis of 3-DPA Lactone via Tandem Cyclization Reaction of Acetonide Protected Methyl 4,5-Dihydroxy-2-chloroglycidate
Takuzo Komiyama, Yutaka Takaguchi, and Sadao Tsuboi*
*Department of Environmental Chemistry and Materials, Faculty of Environmental Science and Technology, Okayama University, 2-1-1 Tsushima-naka, Okayama 700-8530, Japan
Abstract
The novel synthesis of 3-DPA lactone, which is known as a potent food intake-control substance, via tandem cyclization reaction of acetonide protected methyl 4,5-dihydroxy-2-chloroglycidate is described.
Published online: 21st July, 2006
■ Synthetic Studies of Bioactive Quinoxalinones: A Facile Approach to Potent Euglycemic and Hypolipidemic Agents
Sukanta Kamila and Edward R. Biehl*
*Chemistry Department, Southern Methodist University, Dallas, TX 75275-0314, U.S.A.
Abstract
Substituted quinoxalin-2-ones have been prepared in high yields in a one-pot reaction in which a 1:1 mixture of 1,2-diaminobenzene and appropriate ethyl 2-bromoalkyl/aryl acetate is subjected to microwave irradiation in presence of DBU at 190 °C for 6 min A possible mechanism is presented.
Published online: 11th July, 2006
■ New Synthesis of 3-Aryl-2,5-dihydrofurans
Meng-Yang Chang,* Chun-Yu Lin, and Chun-Li Pai
*Department of Applied Chemistry, National University of Kaohsiung, No. 700 Kaohsiung University Rd., Nan-Tzu District, Kaohsiung 811, Taiwan, R.O.C.
Abstract
We present a straightforward synthesis of 3-aryl-2,5-dihydrofurans by ring contraction of 4-aryl-3,6-dihydro-2H-pyrans with the repeated treatment of MCPBA and BF3-OEt2. The building block 3-aryltetrahydrofuran-3-carboxylic acid with potential biological activities was also prepared.
Published online: 30th June, 2006
■ A New Pyrrolidine-2,4-dione Derivative, Vermelhotin, Isolated from Unidentified Fungus IFM 52672
Tomoo Hosoe, Kazutaka Fukushima, Kayoko Takizawa, Takeshi Itabashi, Kenji Yoza, and Ken-ichi Kawai*
*Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
Abstract
A new pyrrolidine-2,4-dione derivative, vermelhotin (1), was isolated along with the characteristic antifungal substance, dihydroepiheveadride (2), and its analog, deoxoepiheveadride (3), from unidentified fungus IFM 52672. The structure of 1 was elucidated by the spectroscopic and X-Ray crystallographic investigation. Velmelhotin (1) was the first example of 3-acylpyrrolidine-2,4-dione (tetramic acid) derivative having further pyrane ring.
Published online: 18th July, 2006
■ Three New Isochromans from the Mycelial Culture of a Cylindrocarpon Fungus
Liangxiong Xu, Jinghua Xue, Hanhong Xu, Xingzhong Liu, Wenzhe Ma, and Xiaoyi Wei*
*South China Bonatical Garden, Chinese Academy of Sciences, Leyiju, Guangzhou 510650, China
Abstract
Three new isochroman derivatives, 1-acetonyl-7-carboxyl-6,8-dihydroxy-3,4,5-trimethylisochroman (1), 7-carboxyl-6,8-dihydroxy-1,1,3,4,5-pentamethylisochroman (2), and 6,8-dihydroxy-3,4,5-trimethylisochroman (3), together with decarboxydihydrocitrinone (4), were isolated from mycelial solid culture of a Cylindrocarpon fungus. Their structures were established by spectroscopic methods.
Published online: 18th July, 2006
■ Microwave-Assisted Synthesis of Pyrazoles by 1,3-Dipolar Cycloaddition of Diazo Compounds to Acetylene Derivatives
Irena Zrinski, Marina Juribasic, and Mirjana Eckert-Maksic*
*Division of Organic Chemistry and Biochemistry, Rudjer Boskovic Institute, P.O. Box 180, HR-10002 Zagreb, Croatia
Abstract
Microwave-assisted preparation of a wide range of 5-ethoxycarbonylpyrazoles and 3-pyrazoles by 1,3-dipolar cycloaddition of diazo compound to acetylenes is described. All reactions were carried out using high throughput sequential technique.
Published online: 11th July, 2006
■ New Dioxomorpholine Derivatives, Javanicunine A and B, from Eupenicillium javanicum
Shou Nakadate, Koohei Nozawa,* Hitoshi Horie, Yuichi Fujii, Masahiro Nagai, Shin-ichirou Komai, Tomoo Hosoe, Ken-ichi Kawai, Takashi Yaguchi, and Kazutaka Fukushima
*School of Pharmaceutical Sciences, Ohu University, 31-1 Misumido, Tomita-machi, Koriyama, Fukushima 963-8611, Japan
Abstract
Two new dioxomorpholine derivatives, javanicunine A (1) and B (2) were isolated from the extract of Eupenicillium javanicum IFM 54704. These structures were determined by chemical and spectroscopic methods.
Published online: 21st July, 2006
■ Solvent-Free Reaction Using Phosphonium Salts: Chlorination of Hydroxyheteroaromatics and Dehydration of Primary Amides
Tatsuya Takahashi, Osamu Sugimoto,* Jiro Koshio, and Ken-ichi Tanji*
*Laboratory of Organic Chemistry, School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan
Abstract
Solvent-free chlorination of heteroaromatics using the phosphonium salt, prepared by reaction of triphenylphosphine with N-chlorosuccinimide, was accomplished by microwave-irradiation or heating to give the corresponding chloroheteroaromatics. Similarly, primary amides was converted into nitriles by this method.