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. 1, 2006
Published online: 28th October, 2005
■ Palladium-catalyzed Cross-Coupling Reaction of 4-Methylthiazole and 2-Trimethylsilylthiazoles with Biaryl Triflates
Osamu Hara, Taiju Nakamura, Fumihiko Sato, Kazuishi Makino, and Yasumasa Hamada*
*Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
Abstract
2-Trimethylsilylthiazoles serve as an efficient counterpart for direct palladium-catalyzed cross-coupling reaction with aromatic triflates without any fluoride anion source to afford 2-arylthiazoles.
Published online: 6th December, 2005
■ Effects of Small Structural Changing on the Kinetic and Thermodynamic Stabilities of Pseudorotaxanes
Yuji Tokunaga,* Tatsuhiro Goda, Nanae Wakamatsu, Ryuji Nakata, and Youji Shimomura
*Department of Materials Science and Engineering, Faculty of Engineering, Fukui University, Bunkyo, Fukui 910-8507, Japan
Abstract
Pseudorotaxanes were synthesized in this study. They comprised secondary ammonium ions and 24-membered crown ethers possessing one-four benzene rings fusing macrocycles. Kinetic and thermodynamic stabilities of the complexes were dependent on their number of benzene rings.
Published online: 29th November, 2005
■ Synthesis of Some Heterocycle Containing Urea Derivatives and Their Anti-viral Activity
Manjusha Verma,* Krishna N. Singh,* and Erik D. Clercq
*Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi-221 005, India
Abstract
Some new isoindol heterocyclic ureas (6a-6i) have been synthesized using N-aminophthalimide (2) and ethyl N-monosubstituted/ethyl N,N-disubstituted carbamate (5a-5i). All the newly synthesized final compounds have been evaluated for their anti-viral activities against a variety of viruses. The compound (6f) with the methoxy substituent showed reasonably better activity as compared to the standard drugs against all the viruses (cf. Tables 1, 2 and 3). Further, all the products (6a-6i) were found to be active against Vesicular stomatitis virus, Coxsackie virus B4 and Respiratory syncytical virus (cf. Table 2) and the compounds (6h) and (6i) displayed better antiviral activity in comparison to Brivudin and (S)-DHPA (cf. Table 3).
Published online: 2nd December, 2005
■ Synthesis of Indolines and Quinoline via Cyclization of N-Arylsulfonyl-2-allylanilines Catalyzed by Brønsted Acid
Yan Yin and Gang Zhao*
*Laboratory of Modern Synthetic Organic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China
Abstract
N-Arylsulfonyl-2-allylanilines underwent the intramolecular hydroamination to produce indolines or quinoline in the presence of catalytic amount of triflic acid with good yield. The scope of the reaction was extended to other N-protected aminoalkenes.
Published online: 15th November, 2005
■ Reactions of α-Diazocamphor with Aromatic Thioketones
Grzegorz Mloston,* Malgorzata Celeda, Anthony Linden, and Heinz Heimgartner*
*Institute of Organic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
Abstract
The reactions of α-diazocamphor (6) with aromatic thioketones (9a-d) in dichloromethane at room temperature afforded mixtures of the stereoisomeric spirocyclic thiiranes (10) and (11). A reaction mechanism via [2+3] cycloaddition to give the spirocyclic 2,5-dihydro-1,3,4-thiadiazoles (13) and (14), subsequent elimination of nitrogen and 1,3-dipolar electrocyclization of the intermediate thiocarbonyl ylide (15) is proposed. The structure of the stereoisomers (10a) and (11a) has been established by X-Ray crystallography. Desulfurization of the mixtures (10/11) with triphenylphosphane in boiling THF yielded the alkylidene derivatives (12).
Published online: 22nd November, 2005
■ Concise Highly Enantioselective Cascade Synthesis of Azacyclooctene Alkaloids with a Quaternary Stereocenter
Daniele Muroni, Antonio Saba,* and Nicola Culeddu
*Department of Chemistry, University of Sassari, Via Vienna 2, I-07100 Sassari, Italy
Abstract
Enantiopure azabicyclo[6.3.0]undecene ring systems bearing a quaternary stereocenter were prepared by a cascade process.
Published online: 15th November, 2005
■ Derivatives of 1,2,3,4-Tetrahydroisoquinoline-3-carboxylic Acid
Petr Jansa, Vladimír Machácek,* and Valerio Bertolasi
*Department of Organic Chemistry, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice, Czech Republic
Abstract
The following derivatives of 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid have been prepared in their (S)-form and as racemates: hydrochloride of methyl ester, N-carboxy anhydride, and N-acetyl derivative. All the substances were fully characterised by elemental analyses, 1H and 13C NMR spectra, and optical rotation, as the case may be; the N-carboxy anhydride was also characterised by means of X-Ray diffraction. Also identified was the intermediate of the reaction of the title acid with phosgene, the N-chlorocarbonyl derivative, and the respective methyl ester was prepared. The dioxopiperazine of the title acid was prepared and characterised both in pure (S,S)-form and in the form of a mixture of two racemates. The optically pure dioxopiperazine was prepared by a reaction of the N-carboxy anhydride in solid phase.
Published online: 15th November, 2005
■ Tandem Radical Cyclization Reactions, Initiated at Nitrogen, as an Approach to the CDE-Tricyclic Cores of Certain Post-secodine Alkaloids
Martin G. Banwell* and David W. Lupton
*Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
Abstract
The nitrogen-radical precursors (10-15) have been prepared and subjected to reaction conditions expected to promote tandem radical cyclization sequences leading to the CDE-tricyclic frameworks associated with alkaloids such as vindoline (1) and ibophyllidine (2). In the event, each of precursors (10, 11, 12 and 13) participated in the desired processes and thus providing products, (28, 29, 30 and 31) respectively, embodying ring systems related to ibophyllidine (2). In contrast, the higher homologue (14), of PTOC-carbamate (12) decomposed upon exposure to radical chain initiation conditions while the N-chloro-analogue (15) simply underwent reductive dechlorination to give compound (27). As such the title processes appear unlikely to offer a useful approach to the CDE-tricyclic ring system associated with vindoline-type alkaloids.
Published online: 15th November, 2005
■ Determination of Absolute Structure of (+)-Davidiol A
Yue-Hua He, Yoshiaki Takaya, Kenji Terashima, and Masatake Niwa*
*Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tenpaku, Nagoya 468-8503, Japan
Abstract
The absolute configurations of stilbenetrimers, (+)-davidiol A and (-)-davidiol A were determined on the basis of the enzymatic chemical transformations.
Published online: 1st November, 2005
■ Synthesis of Naphthothiazolium Salts from BINOL
Osamu Hara, Taiju Nakamura, Kazuishi Makino, and Yasumasa Hamada*
*Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
Abstract
Naphthothiazolium salts with axial chirality were prepared from (S)-BINOL through introduction of a thiol group in place of the hydroxyl group by the Newmann-Kwart rearrangement and construction of the thiazolium ring by treatment of the air-sensitive N-alkylated aminothionaphthol with triethyl orthoformate in the presence of hydrogen chloride.
Published online: 9th December, 2005
■ Shimalactones, Neuritogenic Polyketides from a Marine-derived Fungus Emericella variecolor GF10
Hong Wei, Takuya Itoh, Naoyuki Kotoku, and Motomasa Kobayashi*
*Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Toyonaka, Osaka 560-0043, Japan
Abstract
Shimalactone B (2), a novel polyketide having bicyclo[4.2.0]octadiene and oxabicyclo[2.2.1]heptane units, was isolated as a minor constituent from a cultured marine-derived fungus of Emericella variecolor GF10. The chemical structure of 2 and the structural relationship between shimalactones A and B (2) were determined by detailed NMR and CD spectroscopic analyses and chemical derivatization. Shimalactones A and B (2) induced neuritogenesis against neuroblastoma Neuro 2A cells at 10 μg/mL concentration.
Published online: 6th December, 2005
■ Synthesis of Dibenzo-fused 10-Membered Cyclic Ethers from Isovanillin via Ring-closing Metathesis
Eng-Chi Wang,* Yu-Li Lin, Hsing-Ming Chen, Sie-Rong Li, Chizuko Kabuto, and Yoshio Takeuchi
*Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung City 807, Taiwan, R.O.C.
Abstract
A synthesis of substituted dibenzo-fused 10-membered cyclic ethers is described. 2-Allylbenzyl alcohols and 2-allylphenols derived from isovanillin were coupled by the Mitsunobu reaction to construct intramolecular dienes with ether linkage. The resulting dienes were subsequently treated with Grubbs’ catalyst to undergo ring-closing metathesis to give the desired cyclic ethers.
Published online: 1st November, 2005
■ Convenient Synthesis and Physicochemical Profile of New Derivatives of Pyrimidine
Joanna Cabaj, Jacek Doskocz, Jadwiga Soloducho,* and Antoni Chyla
*Institute of Organic Chemistry, Biochemistry and Biotechnology, Wroclaw University of Technology, Wyb. Wyspianskigo 27, 50-370 Wroclaw, Poland
Abstract
A synthesis of linear oligoheterocycles based on the substituted pyrimidines are described. The desired compounds have been accomplished by the variation of the original Pinner synthesis in which the aliphatic nitrile reacted with hydrogen chloride to give imino ester. These compound reacted with ammonia gas to give amidine. Chalcones in reaction with amidines give bis(phenyl)pyrimidines. The bis(phenyl)pyrimidines reacted with 3,4-ethylenedioxy-2-trimethyltinthiophene or 2-trimethyltinthiophene in the presence of Pd(PPh3)2Cl2 or Pd(PPh3)4 as catalyst to give designed compounds. In this work are presented also some electrochemical measurements using Langmuir - Blodgett technique in mono- and binary systems.
Published online: 28th October, 2005
■ Synthesis and Properties of Luotonin A Homologues and Their Aza-analogues
Eung Seok Lee, Jae Gyu Park, Seung Ill Kim, and Yurngdong Jahng*
*College of Pharmacy, Yeungnam University, Kyongsan 712-749, Korea
Abstract
A series of new 3,2’-polymethylene-2-(quinol-2-yl)-4(3H)-quinazolinones and their aza-analogues were prepared as a homologous series of luotonin A. Their inhibitory activities against topoisomerase and cytotoxicities against selected cancer cell lines were evaluated to show that luotonin A and its aza-analogue were shown significant cytotoxicity. Conformational study revealed that trimethylene-bridged systems were rigid at room temperature with activation energies for interconversion of 15.7 and 14.6 kcal/mol for 3,2’-trimethylene-2-(quinol-2-yl)-4(3H)-quinazolinone and its aza-anlogue, respectively.
Published online: 15th November, 2005
■ New Abietane Diterpene Alkaloids Possessing an Oxazole Ring from Salvia trijuga
Fu-Wen Lin, Amooru G. Damu, and Tian-Shung Wu*
*Department of Chemistry, National Cheng Kung University, 1, Ta-Shiueh Rd., Tainan, 70101, Taiwan, Taiwan, R.O.C.
Abstract
Two new diterpene alkaloids, isosalviamine-A (1) and B (2) and nine known tanshinones (3-11) were isolated from the MeOH extract of roots of S. trijuga. The structures of these new compounds were elucidated from 1H and 13C NMR spectra with the aid of COSY, NOESY, HMQC and HMBC experiments.
Published online: 1st November, 2005
■ A New Efficient Synthesis of 5-Aryloxazoles from Arylidene Diacetates and Application to the Preparation of BMS-337197, a Novel IMPDH Inhibitor
Bang-Chi Chen,* Mark S. Bednarz, Huiping Zhang, Rulin Zhao, T. G. Murali Dhar, Balu Balasubramanian, and Joel C. Barrish
*Discovery Chemistry, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ 08543-4000, U.S.A.
Abstract
A new method for the synthesis of 5-aryloxazoles is described. Treatment of arylidene diacetates with one equivalent of TosMIC reagent in the presence of excess of potassium carbonate in methanol afforded 5-aryloxazoles in “one-pot” in 90-94%. Heteroarylidene diacetates reacted in a similar way. Application of the new method to the synthesis of the novel IMPDH inhibitor BMS-337197 is also presented.
Published online: 2nd December, 2005
■ Microwave-assisted Synthesis of N-Arylglycines: Improvement of Sydnone Synthesis
Davood Azarifar,* Hassan Ghasemnejad Bosra, Mohammad-Ali Zolfigol, and Mahmood Tajbaksh
*Department of Chemistry, School of Science, Bu-Ali Sina University, Hamadan 65174, Iran
Abstract
Reactions of anilines with ethyl bromoacetate under microwave irradiation have afforded N-arylglycines that are subsequently converted to their N-nitroso derivatives with a combination of silica chloride or periodic acid, wet SiO2 and sodium nitrite in CH2Cl2 with satisfactory yields. In the final step, the use of 1,3-dibromo-5,5-dimethylhydantoin (DBH) as a new and effective reagent for dehydration of N-nitroso-N-arylglycines to sydnones was successfully examined.
Published online: 18th November, 2005
■ A Stereocontrolled Formal Asymmetric Synthesis of Pseudodistomin C
Ken-ichi Tanaka,* Takuya Maesoba, and Hiroyuki Sawanishi
*Faculty of Pharmaceutical Sciences, Hokuriku University, 3-Ho, Kanagawa machi, Kanazawa 920-1181, Japan
Abstract
An efficient and stereocontrolled formal asymmetric synthesis of pseudodistomin C has been achieved by employing intramolecular transamidation reaction, exo-methylenation, and highly stereoselective hydroboration. The resulting 2-hydroxymethylpiperidine derivative (15) was further converted into the key intermediate (2) for the synthesis of pseudodistomin C.