Regular Issue

Vol. 38, No. 10, 1994

20 data found. 1 - 20 listed
Communication | Regular issue | Vol 38, No. 10, 1994, pp. 2147 - 2151
Published online:
DOI: 10.3987/COM-94-6793
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.


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.

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Communication | Regular issue | Vol 38, No. 10, 1994, pp. 2153 - 2158
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DOI: 10.3987/COM-94-6802
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


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.

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Communication | Regular issue | Vol 38, No. 10, 1994, pp. 2159 - 2163
Published online:
DOI: 10.3987/COM-94-6813
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


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.

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Communication | Regular issue | Vol 38, No. 10, 1994, pp. 2165 - 2169
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DOI: 10.3987/COM-94-6848
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


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.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2171 - 2181
Published online:
DOI: 10.3987/COM-94-6746
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


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.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2183 - 2189
Published online:
DOI: 10.3987/COM-94-6784
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


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

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2191 - 2198
Published online:
DOI: 10.3987/COM-94-6794
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


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.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2199 - 2204
Published online:
DOI: 10.3987/COM-94-6795
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


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.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2205 - 2218
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DOI: 10.3987/COM-94-6798
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


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.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2219 - 2229
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DOI: 10.3987/COM-94-6819
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


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.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2231 - 2241
Published online:
DOI: 10.3987/COM-94-6821
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


(+)-Methyl dihydroepijasmonate (2) was synthesized starting from levoglucosenone (1) in an optically pure state.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2243 - 2246
Published online:
DOI: 10.3987/COM-94-6822
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.


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.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2247 - 2252
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DOI: 10.3987/COM-94-6824
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


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.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2253 - 2260
Published online:
DOI: 10.3987/COM-94-6828
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


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).

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2261 - 2265
Published online:
DOI: 10.3987/COM-94-6830
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


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

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2267 - 2276
Published online:
DOI: 10.3987/COM-94-6833
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


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).

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2277 - 2288
Published online:
DOI: 10.3987/COM-94-6837
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


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.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2289 - 2293
Published online:
DOI: 10.3987/COM-94-6839
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


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.

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Paper | Regular issue | Vol 38, No. 10, 1994, pp. 2295 - 2308
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DOI: 10.3987/COM-94-6840
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


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.

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Review | Regular issue | Vol 38, No. 10, 1994, pp. 2309 - 2342
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DOI: 10.3987/REV-93-460
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


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.

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20 data found. 1 - 20 listed