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. 38, No. 10, 1994
Published online:
■ Macrocycle Formation via Arylnitrenium Ions: Possible Intramolecular Recognition
Rudolph A. Abramovitch* and Qing Shi
*Department of Chemistry, Clemson University, Clemson, SC 29631, U. S. A.
Abstract
MMX calculations on 1-(4-nitrophenyl)-9-phenylnonane indicate that it has a global minimum energy conformation in which the aryl rings are within easy bonding distance, which is confirmed by 2D NOESY, ultraviolet and fluorescence spectroscopy; the corresponding arylnitrenium ion cyclizes to give mainly the 18-membered ring 4,4‘-nonamethylenediphenylamine, which results suggest that when electron-deficient and electron-rich aryl rings are joined by a long, flexible chain there exists an intramolecular attractive interaction between them that pre-orients them for cyclization.
Published online:
■ Synthesis and Properties of Tetrathiafulvalene Derivatives Containing Quinoid Structures: Novel Electron Donors of Organic Conductors
Katsuhiro Saito,* Chikayuki Sugiura, Emi Tanimoto, Katsushi Saito, and Yoshiro Yamashita
*Faculty of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
Abstract
Wittig-Horner reactions of 2-dimethoxyphosphinyl-1,3-dithiole derivatives with a benzoquinone-cyclopentadiene adduct and anthraquinone afforded new types of electron donors with alkylthio groups for organic conductors which showed reversible oxidation waves on cyclic voltammetries and formed conductive charge-transfer complexes with TCNQ or DDQ.
Published online:
■ Isolable Atropisomers of 2-Aryl Substituted Indoline Derivatives. MO Analysis of Restricted Rotation
Masashi Eto, Fumikazu Ito, Takeo Kitamura, and Kazunobu Harano*
*Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-hon-machi, Kumamoto 862-0973, Japan
Abstract
The ground- and transition-state structures for restricted rotation of isolable atropisomers of 1-(4‘-chlorobenzoyl)-2-(2"-hydroxynaphtyl)-3,3-dimethylindoline are calculated by AM1 method. The X-ray structural features of the atropisomers are approximately reproduced. Inspection of the transition-state structures indicates the presence of close nonbonded H/H contacts between the methyl hydrogens and the aromatic hydrogens. Based on the calculation data, the mechanism of the restricted rotation is discussed.
Published online:
■ Novel Ring Expansion Reaction of Epoxides and Oxetanes Accompanied by Rearrangement of Ethereal Functional Groups
Akichika Itoh, Yukihiro Hirose, Hirotaka Kashiwagi, and Yukio Masaki*
*Gifu Pharmaceutical University, 6-1 Mitahora-higashi 5-chome, Gifu 502-8585, Japan
Abstract
Small cyclic ethers, epoxides and oxetanes, possessing ethereal groups on the side chain, was found to rearrange by means of Lewis acid catalysts, BF3·EtO2, to give ring expanded cyclic ethers accompanied by transfer of the ethereal groups. Formation of tetrahydro-furan and pyran ring and transposition of benzylic and allylic groups of the ethereal function were observed to be favorable.
Published online:
■ A New Type of Highly Polar 1,3-Dipoles. Synthesis and Chemistry of Thiocarbonyl-stabilized Pyrazolidinazomethineimies
Helmut Dorn* and Thomas Kreher
*Abt. Organische Synthese, Institut für Angewandte Chemie Berlin-Adlershof, Rudower Chaussee 5, D-12489, Berlin, Germany
Abstract
3-Thioxopyrazolidine-azomethineimines (2) are synthesized from their 3-oxo analogues (1) and Lawesson‘s reagent (LR). The electron structures of 1 and 2 resemble those of polymethines, dipole moments of 2 are even higher than those of 1; further physical organic data are discussed. With NaBH4 2 gives 3-thioxopyrazolidines (8). These are S-mono- (10) and (N-1), S-bisalkylated (11). S-Alkylation of 2 affords pyrazolinium salts (7). 1,3-Dipolar cycloaddition of enamines to 2 results in [p4S +p2S] products (12, 13), HOMO/LUMO energies of 1 and 2 are given. Models of γ-thiolactams (17, 19), mimicing antibiotics, are gained via 1,3-dipolar cycloadducts of 1 with LR.
Published online:
■ Synthesis of Dinitroxides of Potential Use as Contrast Agent in MRI
Mohab-Eddine Brik,* Marguerite Van Duong Nguyen, Louisette Nicolas, Jacques Courtieu, and Alain Gaudemer
*Laboratoire de Chimie Structurale Oranique, ICMO, Bat 410, U.R.A. CNRS 1384, Université Paris-Sud, Orsay 91405, Paris Cedex, France
Abstract
Dinitroxides derived from 6-alkyl-1,4,8,11-tetraaza undecane-5,7-dione have been synthesized in three steps. These compounds, which contain two paramagnetic centers, are more effective proton relaxation agents than those containing only one nitroxyl moiety and could be used in smaller quantities as contrast agents in MRI
Published online:
■ Synthesis of 3‘-Azido- and 3‘-Amino-2‘,3‘-dideoxynucleosides from 2,4-Quinazolinediones
Ahmed A. El-Barbary, Nasser R. El-Brollosy, and Erik B. Pedersen*
*Department of Chemistry, Odense University, Campusvej 55 DK-5230 Odense M., Denmark
Abstract
2,4-Quinazolinediones (1) were silylated and condensed with methyl 3-azido-5-O-tert-butyldiphenylsilyl-2,3-dideoxy-D-erythro-pentofuranoside (3) in the presence of TMS triflate to afford the corresponding 3‘-azido nucleosides (4). Deprotection of 4 using Bu4NF/THF at room temperature gave 1-(3-azido-2,3-dideoxy-α-D-erythro-pentofuranosyl)-2,4-quinazolinediones (5) and the corresponding β-anomers (6). Treatment of compound (6b) with triphenylphosphine in pyridine, followed by hydrolysis with aqueous ammonium hydroxide yielded 6-methyl-1-(3-amino-2,3-dideoxy-β-D-erythro-pentofuranosyl)-2,4-quinazolinedione (7) which was also obtained when silylated 6-methyl-2,4-quinazolinedione (2b) was condensed with 1,5-di-O-acetyl-2,3-dideoxy-3-phthalimido-β-D-erythro-pentofuranose (8) in acetonitrile followed by deprotection with MeNH2/EtOH.
Published online:
■ N-1 Oxidation of Adenine Substituted at N-9 by an Olefinic Chain
René Beugelmans,* André Lechevallier, Rachid Benhida, Tawfik Gharbaoui, and Angela Morris
*Institut des Chimie des Substances Naturelles, C.N.R.S., Avenue de la Terrasse, Bat. 27, 91198 Gif-sur-Yvette Cedex, France
Abstract
The oxidation of 9-vinyladenine derivatives (1a-c) with m-chloroperoxybenzoic acid (MCPBA) leads selectively to the corresponding N-1 oxides (2a-c) and when the 6-amino group is protected, the oxidation occurs in the double bond of the olefinic chain to give the epoxides (6a, b) selectively.
Published online:
■ The Regiochemistry of 6- and 7-Chloro-5,8-quinolinequinones
Sophie Lévesque and Paul Brassard*
*Département de Chimie, Faculté des Sciences et de Génie, Université Laval, Cité Universitaire, Québec, G1K 7P4, Canada
Abstract
The cycloaddition of 1-aza-1,3-dienes to benzoquinones, specifically halogenated benzoquinones, has been carried out successfully. The comparison of products so obtained with substances of known structure confirms the orientation of the process as previously postulated. It has also been shown that the regiochemistry of the reactions is determined by the sole position of the halogen and is independent of any other electronic effect. Other regiospecific transformations have been observed using the chloroquinolinequinones now made readily available. Finally, useful correlations of structures to nmr spectra have also been drawn.
Published online:
■ Sesquiterpene Pyridine Alkaloids from Maytenus chuchuhuasca
Osamu Shirota, Akiko Otsuka, Hiroshi Morita, Koichi Takeya, and Hideji Itokawa*
*Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
Abstract
Structural elucidations of seven novel sesquiterpene pyridine alkaloids, chuchuhuanines E-1 (1), E-II (2), E-III (3), E-IV (4), E-V (5), W-I (6) and 4-deoxyeuonymine (7), which were isolated along with seven known alkaloids from root barks of Maytenus chuchuhuasca Raymond-Hamet et Colas (Celastraceae), are presented. Their structures with a novel dihydro-β-agarofuran type sesquiterpene core, linking several ester moieties and including a fifteen or sixteen membered macrocyclic diester ring system, were elucidated by mainly spectroscopic methods.
Published online:
■ Synthesis of (+)-Methyl Dihydroepijasmonate
Takashi Ebata,* Katsuya Matsumoto, and Hajime Matsushita
*Life Science Research Laboratory, Japan Tobacco Inc., 6-2, Umegaoka, Midori-ku, Yokohama, Kanagawa 227-8512, Japan
Abstract
(+)-Methyl dihydroepijasmonate (2) was synthesized starting from levoglucosenone (1) in an optically pure state.
Published online:
■ Improved Process for the Preparation of 2-Methyl-3-trifluoromethylaniline: A Versatile Intermediate for Flunixin Synthesis
Rabih Jaouhari* and Philip Quinn
*QUCHEM, Custom Synthesis and Process Development Research Centre, School of Chemistry, The Quee‘s University of Belfast, David Keir Kuilding, Belfast, BT9 5AG, U.K.
Abstract
A detailed new experimental investigation into the synthesis of Flunixin via 2-methyl-3-trifluoromethylaniline is described. The coupling process between 2-methyl-3-trifluoromethylaniline and 2-chloronicotinate was achieved stoichiometrically and in high yield, when ethylene glycol was used as reaction solvent at 160 °C.
Published online:
■ Cyclic Peptides from Higher Plants. Part 8. Three Novel Cyclic Pentapeptides, Astins F, G and H from Aster tataricus
Hiroshi Morita, Shinji Nagashima, Koichi Takeya, and Hideji Itokawa*
*Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
Abstract
Three novel cyclic pentapeptides, named astins F (1), G (2) and H (3), which two of them contain one chlorine atom, have been isolated from Aster tataricus (Compositae) and their structures were elucidated by spectroscopic evidence, chemical degradation and chemical transformation from astin C to 2.
Published online:
■ Stereoselective Syntheses of cis- and trans-Hexahydrocyclopenta[c]pyran-3(1H)-ones
Masashi Ohba,* Tsuyoshi Haneishi, and Tozo Fujii
*Faculty of Pharmaceutical Scicences, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan
Abstract
A new access to cis- and trans-hexahydrocyclopenta[c]pyran-3(1H)-ones (1 and 2) has been accomplished stereoselectively through 4-step and 5-step routes, respectively, starting from 2-(hydroxymethyl)cyclopentanone (3).
Published online:
■ Synthesis of Bissydno[3,4-a:4‘,3‘-c]quinoxaline: A Heteroaromatic Fused-Ring Bismesoionic System
Wing Lai Chan* and James A. Waite
*Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic, Hung Hom, Kowloon, Hong Kong
Abstract
The synthesis of 1,2-di(sydnonyl)benzene (7a) and its conversion to the heteroaromatic fused-ring bismesoionic system, bissydno[3,4-a:4‘,3‘-c]quinoxaline (3) have been reported
Published online:
■ Cyclization Reactions of 2,2‘-Bis-N-methylindolyl to Potential Protein Kinase C Inhibitors
Ulf Pindur,* Young-Shin Kim, and Dieter Schollmeyer
*Department of Chemistry and Pharmacy, Institute of Pharmacy, University of Mainz, Saarstrasse 21, D-55122 Mainz, Germany
Abstract
2,2‘-Bis-N-methylindolyl (4) was used as the starting material in the syntheses of some indolo[2,3-a]carbazoles (6, 7, and 10a,b). Compounds of this type represent the subunit of the staurosporine group of substances, a natural class of protein kinase C inhibitors. Reaction of the bisindolyl (4) with 1,2,4,5-tetrazine-3,6-dicarboxylate — in the sense of a Diels-Alder reaction with inverse electron demand — gave rise to the pyridazino[b]indoles (11b,11b‘) as an isolable mixture of diastereomers and additionally to a rearranged product (13).
Published online:
■ Photochemical Arylaminomethylation of the Pyrazine Derivatives having Electronegative Substituents
Mamoru Igarashi and Masaru Tada*
*Department of Chemistry, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
Abstract
5,6-Dichloropyrazine-2,3-dicarbonitrile (1), 2,3-dichloroquinoxaline (2), and pyrazine-2,3-dicarbonitrile (3) were photolyzed in acetonitrile in the presence of N-acyl-N-trimethylsilylmethylanilines (4 or 5). The photolysis is proposed to give an N-acylanilinomethyl radical by an electron transfer followed by the rupture of a trimethylsilyl cation. The anilinomethyl radical thus formed couples with the radical anion from the diazines to give the substitution products (6-9 and 11-14) of 1-3.
Published online:
■ 5H-[1,2,4]Oxadiazolo[5,4-d][1,5]benzothiazepines: Synthesis and Stereochemistry
Alba Chimirri,* Rosaria Gitto, Silvana Grasso, Pietro Monforte, and Maria Zappalà
*Dipartimento Farmaco-Chimico, Università di Messina, Viale Annunziata, 98168 Messina, Italy
Abstract
The functionalization of the thiazepine system by 1,3-dipolar cycloaddition of benzonitriloxide to the C=N double bond of 1,5-benzothiazepine derivatives, is described. The configurational and conformational properties of the 3a,4-dihydro-1-phenyl-5H-[1,2,4]oxadiazolo[5,4-d][1,5]benzothiazepines have been determined by nmr spectroscopy assisted by NOE measurements.
Published online:
■ Synthesis of GABA-Analogous Spirocyclic Amino Acids, 4. N-Benzyl-2-azaspiro[4.4]nonane-6-carboxylates
Gabriele Hollauf and Ernst Urban*
*Institute of Pharmaceutical Chemistry, University of Vienna, Währinger Straße 10, A-1090 Vienna, Austria
Abstract
Alkylation of 2-oxocyclopentanecarboxylate (4) with 1,2-dibromoethane and reaction with benzylamine gave 2-azaspiro[4.4]nonane-1,6-dione (7). After selective reduction of 7 at the lactam function, we obtained 2-azaspiro[4.4]nonan-6-one (9) which was treated with TosMIC/tert-BuOK to yield a mixture of diastereomeric nitriles (11a) and (11b). Hydrolysis followed by esterification and mplc separation led to diastereomerically pure esters (3a) and (3b) which represent novel analogs of GABA with restricted conformational flexibility.
Published online:
■ Organosilicon and Organotin Compounds in the Synthesis and Transformation of β-Lactams
Grigory A. Veinberg and Edmunds Lukevics*
*Latvian Institute of Organic Synthesis, 21, Aizkraukles, LV 1006, Riga, Latvia
Abstract
The present review describes the general trends in the synthesis and structural modification of β-lactams based on the employment of organosilicon and organotin compounds.