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. 14, No. 11, 1980
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■ 2-Methoxybenzylidene Acetals, Efficient Protecting Groups for Aldohexopyranosides
Vernon Box,* Rawle Hollingsworth, and Earle Roberts
*Department of Chemistry, Mona Campus, University of the West Indies, Mona, Kingston 7, Jamaica
Abstract
2-Methoxybenzaldehyde dimethyl acetal is an excellent protecting group for aldohexopyranosides by way of the formation of their 4,6-O-(2-methoxybenzylidene) acetals.
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■ Prediction of Site Selectivity in Photocyclization of Seven Membered Ring Compounds (2): Background Involved in Reactivity Index ΔGrs and Comparison with the Empirically Deduced Polarization Model
Takahiro Tezuka* and Osamu Kikuchi
*Department of Chemistry, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba-shi, Ibaraki, 305-8571, Japan
Abstract
The quantitative background of the index ΔGrs proposed by us previously is presented in this paper; a new reactivity index ΔErs is derived. These indices are compared with the empirically deduced polarization model proposed by Brember et al. Some applications of ΔGrs to the photocyclization of tropolone and azepine derivatives are described.
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■ Synthesis of 2-Aryl-benzimidazoles via Cyclic N-Diazonium Ions
Richaed Kreher* and Udo Bergmann
*Institut für Chemie, Medizinische Hochschule Lübeck, Ratzeburger Allee 160, D-2400, Germany
Abstract
Condensation of 2-azido-aniline with aromatic aldehydes and protonation with tetrafluoroboric acid lead to phenylogous azidoiminium salts. Subsequent cyclisation to cyclic N-diazonium ions and N2-elimination give rise to the formation of 2-aryl-benzimidazoles. In the same manner 2-azido-N-methylaniline can be converted with aromatic aldehydes through a one step procedure into the corresponding 1-methyl-2-aryl-benzimidazoles. The common reaction principle is the intermediate formation of cyclic N-diazonium salts as precursors for 5-membered heterocycles.
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■ Synthesis and Sodium Borohydride Reduction of 3,9-Dimethyladenine Perchlorate Deuterated at the 2-Position
Tozo Fujii,* Tohru Saito, Tsuyoshi Nakasaka, and Kyoko Kizu
*Faculty of Pharmaceutical Scicences, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan
Abstract
The NaBH4 reduction of 3,9-dimethyladenine perchlorate (Ib) in MeOH was found to give the 1,2-dihydro derivative III. The structure of III was confirmed by a similar reduction of the 2-deuterated isomer XIV, which was synthesized from the methylaminoimidazole VI through the deuteroformamido derivatives VIII and XI. 3-Benzyl-9-methyladenine-2-d perchlorate (XV) was similarly prepared from the N-benzylformamidoimidazole V through the deformylated derivative VII and the deuteroformamido derivatives IX and XII. Comparison of the nmr spectra of Ib and 3-benzyl-9-methyladenine perchlorate (Ie) with those of XIV and XV permitted a distinction between C(2)- and C(8)-proton signals observed for 3,9-dialkyladenine salts (Ia-1); the C(2)-proton resonates at lower field than does the C(8)-proton.
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■ A Simple Synthesis of Bicyclo[2.2.1]heptane System, a Key Potential Intermediate for Stable Prostaglandin H2 Analogue
Toshio Suzuki, Akiko Tomino, Yasuyuki Matsuda, Katsuo Unno, and Tetsuji Kametani*
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
A simple and efficient synthesis of 6-cyanomethyl-1-methoxycarbonylbicyclo[2.2.1]heptane system leading to stable prostaglandin H2 analogue is described.
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■ Synthesis of Δ3-Dihydrothiapyran-1,1-dioxides and Their Ramberg-Bäcklund Conversion to Cyclopentadienes
Jack J. Burger, Tjoe B. R. A. Chen, Eddy R. de Waard,* and Henk O. Huisman
*Department of Organic Chemistry, University of Groningen, Nijenborgh 16, 9747 AG Groningen, The Netherlands
Abstract
Treatment of Z-sulfone 1 with n-BuLi gives complete conversion to the cyclized anion 3. The anion 3 is protonated to 4. Reaction of 3 with hexachloroethane leads to a mixture of 4, 5 and 6. Ramberg-Bäcklund rearrangement of 5 with one equivalent of n-BuLi affords 6 and 7. The same reaction with 6 gives 8.
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■ 13C Nuclear Magnetic Resonance Spectra of Corilagin and Geraniin
Takashi Yoshida and Takuo Okuda*
*Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
Abstract
The 13C nmr spectra of corilagin and its derivatives have been recorded and the signals of all carbons assigned. The analysis has been extended to geraniin.
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■ The Structure of Cammaconine from Aconitum variegatum
Naresh V. Mody, S. William Pelletier,* and Nikola M. Mollov
*Department of Chemistry, Institute for Natural Products Research, The University of Georgia, Chemistry Building, Athens, Georgia 30602-2556, U.S.A.
Abstract
The novel structure assigned earlier to the C19-diterpenoid alkaloid, commaconine, contained a C(16) hydroxyl and a C(18) methoxyl group. On the basis of 13C NMR spectral analysis, these assignments have been reversed.
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■ Diazo Coupling Reactions of Amino and of Mercaptopyrimidines
Derek T. Hurst,* Anthony D. Stacey, and Deepthi K. Weerasinghe
*School of Analytical and Biological Chemistry, Kingston Polytechnic, Kingston-on-Thames, KT1 2EE, U.K.
Abstract
Diazo coupling reactions of aminopyrimidines can result in the formation of diazoamino compounds, arylhydrazones of pyrimidine-4-aldehydes by attack at a methyl group or 5-substitution depending on the pyrimidine, the conditions and the reagent. Unless precautions are taken to remove excess nitrous acid deamination can also occur. In the case of mercaptopyrimidines arylation of the mercapto group is the favoured reaction in many cases.
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■ The Mesoionic System 3-Methyl-4-phenyl-1,2,3-thiadiazolium-5-thiolate, Synthesis and X-Ray Structure Determination
Sergio Auricchio,* Sergio Brückner, Luciana Malpezzi Giunchi, and Valeri A. Kozinsky
*Istituto di Chimica, Politecnico di Milano, via Golgi 39, 20133 Milano, Italy
Abstract
We report the synthesis and the crystal structure determination of 3-methyl-4-phenyl-1,2,3-thiadiazolium-5-thiolate which belongs to a mesoionic system which has only recently been investigated.
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■ Synthesis of Some Heterocyclic Compounds with Bridgehead Nitrogen Atoms
M. R. Chaurasia and Surendra K. Sharma*
*Department of Chemistry, D. A. V. (P. G.) College, Dehra Dun, India
Abstract
3,5-Dimethyltriazolo[4,3-c]quinazoline, 5-methyltetrazolo[1,5-c]quinazoline, 5-methyl-s-triazolo[4,3-c]quinazoline-3(2H)-thione, 2-[(5-methyl-s-triazolo[4,3-c]quinazolin-3yl)-thiol]-N,N-benzylphenylacetanilide, hydrochlorides of 3-substituted phenyl-6-diethylaminoimidazolo[2,1-b]thiazoles and 5-methyl-3-(N,N-diethylamino)thiazolo[3,2-c]quinazolin-4-ium chloride have been synthesised. The pharmacological screening of some compounds is also reported.
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■ Synthesis and Structural Assignment of Naturally Occuring 3-Benzyl-6-benzylidene-2,5-piperazinedione
Chung-gi Shin,* Haruo Kato, Yasuchika Yonezawa, Masato Hayakawa, and Juji Yoshimura
*Departmnet of Applied Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan
Abstract
Four possible stereoisomers of 3-benzyl-6-benzylidene-2,5-piperazinedione were synthesized, and the configuration of the natural product isolated from Streptomyces noursei was determined to be (3R, 6Z). It was found that the sign of the optical rotations and the Cotton effect are reversed only by the difference of the (E)- or (Z)-geometry.
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■ Stereoselective Synthesis of (±)-Dihydrocorynantheol via Enamine Annelation
Tetsuji Kametani,* Naoaki Kanaya, Hiroaki Hino, Shyh-Pyng Huang, and Masataka Ihara
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
A facile stereoselective synthesis of (±)-dihydrocorynantheol (8) was achieved via the key step of enamine annelation using 3,4-dihydro-1-methyl-β-carboline (1) and dimethyl 3-methoxyallidenemalonate (2).
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■ A General Approach to the Synthesis of Substituted 5a,11a-Dehydro[1]benzopyran[4,3-c][1]benzopyran-5-ones
Vernon G. S. Box* and Clement G. Humes
*Department of Chemistry, Mona Campus, University of the West Indies, Mona, Kingston 7, Jamaica
Abstract
A general approach to the syntheses of 5a,11a-Dehydro-[1]benzopyran[4,3-c][1]benzopyran-5-ones by the Claisen rearrangement of 3-bromo-4-Aryloxymethylcoumarins is outlined. The possible uses of these 5a-11a-Dehydro-[1]benzopyran[4,3-c][1]benzopyran-5-ones in the syntheses of isoflavanoids and rotenoids are discussed.
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■ Cyclization of 2-(Γ-Bromoacetoacetamido)pyridine Derivatives: Formation of N-Aryl-Γ-lactam Derivatives
Katsumi Tabei,* Hideharu Ito, and Toyozo Takada
*Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
Abstract
1-(2-Pyridyl)-4-hydroxy-2-pyrrolidone (7) was obtained from 2-(γ-bromoacetoacetamido)pyridine (1) through the reduction of the β-carbonyl group with NaBH4, protection of the hydroxyl group by tetrahydropyranyl group, cyclization of the ether to a γ-lactam by using DBU, and subsequent hydrolysis of the ether. According to the similar synthetic process, 1-phenyl-4-hydroxy-2-pyrrolidone (8a) and 1-(p-methoxyphenyl)-4-hydroxy-2-pyrrolidone (8b) were derived from the corresponding γ-bromoacetoacetanilide derivatives.
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■ Sanggenon A, A New Flavanone Derivative from Chinese Crude Drug "Sang-Bái-Pí" (Morus Root Bark)
Taro Nomura,* Toshio Fukai, Yoshio Hano, Yasuko Sugaya, and Takamichi Hosoya
*School of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan
Abstract
From the benzene extract of the Chinese crude drug “Sang-Bái-Pí” (Japanese name Sohakuhi), the root bark of Morus sp. (Moraceae), a novel isoprene substituted flavanone, sanggenon A, was isolated whose structure was shown to be I on the basis of spectral data.
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■ A Transformation of Tetrahydroberberine to a Retroprotoberberine
Miyoji Hanaoka,* Mitsuru Inoue, Shingo Yasuda, and Takeshi Imanishi
*Faculty of Pharmaceutical Scicences, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan
Abstract
The retroprotoberberine (8) was synthesized from tetrahydroberberine (4) via the urethane (6) and the aminoalcohol (7).
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■ Cycloaddition Reactions of Pyridines
Wanda Sliwa*
*Institute of Organic Chemistry, Biochemistry and Biotechnology, Wroclaw University of Technology, Wyb. Wyspianskigo 27, 50-375 Wroclaw, Poland
Abstract
Examples of cycloaddition reactions of pyridines and related compounds, as well as pyridinium N-methylides and pyridinium N-imino-ylides are reported.
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■ Synthesis of Reduced Furans and 3(2H)-Dihydrofuranones with Manipulable Functionality
J. E. Semple and M. M. Joullié*
*Department of Chemistry, University of Pennsylvania, 231 South 34th Street Philadelphia, PA 19104-6323, U.S.A.
Abstract
Recent advances in the synthesis of functionalized, naturally occurring or synthetically useful reduced furans and 3(2H)-dihydrofuranones are reviewed.