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. 45, No. 7, 1997
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■ Glycosyl Phosphoramidimidates as Versatile Glycosyl Donors
Mei-Jin Chen, Krish Ravindran, Donald W. Landry,* and Kang Zhao*
*Department of Chemistry, New York University, 31 Washington Place, New York, NY 10003, U.S.A.
Abstract
A Staudinger reaction of glycosyl phosphoramidites with phenyl azide provides an efficient procedure to access phosphoramidimidates. Their application as glycosyl donors in glycosidation is also described.
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■ The Reactin of Tetrazolylimines with Grignard Reagents
Sung-eun Yoo* and Young-dae Gong
*Pharmaceutical Division, Korea Research Institute of Chemical Technology, P.O. Box 107, Yusung, Taejon 305-343, Korea
Abstract
The addition of alkyl Grignard reagnets on 1-benzyltetrazole imines occurs at the nitrogen atom to give the corresponding N-alkylated tetrazole amines (the azophilic prodcut). In contrast the same reagents on the 2-benzyltetrazole imines exclusively attack the imino carbon (the carbophilic product).
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■ Total Syntheses of N-Trifluoroacetyl-L-daunosamine, N-Trifluoroacetyl-L-acosamine, N-Benzoyl-D-acosamine, and N-Benzoyl-D-ristosamine from an Achiral Precursor, Methyl Sorbate
Machiko Ono, Chikako Saotome, and Hiroyuki Akita*
*School of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan
Abstract
A conjugated addition of benzylamine to methyl (4R,5S)-4,5-(isopropylidenedioxy)-(2E)-hexenoate (12) followed by lactonization under acidic condition proceeds formally to the total syntheses of L-daunasamine (1) and L-acosamine (2). On the other hand, direct conjugated addition of benzylamine to methyl (4S,5S)-4,5-epoxy-(2E)-hexenoate (4) and the subsequent intramolecular nucleophilic attack by ester carbonyl group against epoxy ring of the substrates leads to the formal total syntheses of D-acosamine (2) and D-ristosamine (3).
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■ Simple Total Syntheses of (-)-Ergot Alkaloids and Thier (+)-Enantiomers by a Common Synthesis Method Utilizing Optical Resolution
Masanori Somei* and Kyoko Nakagawa
*Faculty of Pharmaceutical Scicences, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan
Abstract
The first and simple total syntheses of (-)-isochanoclavine-I ((-)-1b), (-)-agroclavine ((-)-3), (-)-agroclavine-I ((-)-4), and (-)-norchanoclavine-I ((-)-5c) and their (+)-enantiomers are achieved from indole-3-carboxaldehyde (8) by a common synthesis method utilizing optical resolution. Absolute configuration of (-)-agroclavine-I is determined to be 5R and 10S for the first time. Preparations of both enantiomers of chanoclavine-I (1c) are also included.
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■ A Nonplanar Thiophene, 3,4-DI-tert-butyl-2,5-bis(triisopropylsilyl)thiophene
Juzo Nakayama,* Ting Yu, Yoshiaki Sugihara, Akihiko Ishii, and Shigekazu Kumakura
*Department of Chemistry, Faculty of Science, Saitama University, Saitama, Saitama 338-8570, Japan
Abstract
Treatment of 2,5-dibromo-3,4-di-tert-butylthiophene with tert-butyllithium followed by reaction with triisopropylsilyl chloride gave a highly congested thiophene, 3,4-di-tert-buty-2,5-bis(triisopropylsilyl)thiophene, whose thiophene ring is no longer planar.
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■ Condensation Reactions of a Nitrodienamine with Grignard Reagents Prepared from Phenyl Bromide, Bromotoluene, Indoles, and Carbazole
Takeshi Koike,* Masanori Hagiwara, Naoki Takeuchi, and Seisho Tobinaga
*Showa Pharmaceutical University, 3-3165, Higashi-tamagawagakuen, Machida, Tokyo 194-8543, Japan
Abstract
Condensation reactions of a nitrodienamie (1) with Grignard reagents prepared from phenyl bromide, 4-bromotoluene, indole (6a), 3-methylindole (6b), 2,3-dimethylindole (6c), 3-cyanomethylindole (6d), and carbazole (6e) were investigated.
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■ Reaction of Thiobenzophenones with Norbornadiene: Unusual Formation of a Seven-membered Cyclic Sulfide
Kentaro Okuma,* Kyoko Shiki, Takafumi Shirokawa, Kazuki Kojima, and Kosei Shioji
*Department of Chemistry, Faculty of Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
Abstract
Reaction of thiobenzophenone with 2,5-norbornadiene afforded an unusual seven-membered cyclic sulfide whereas 4,4’-dimethoxythiobenzophenone reacted with 2,5-norbornadiene to afford the corresponding quinone derivative via [4+2] type cycloaddition reaction. The mechanisms of these reactions are discussed.
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■ Aziridination and 1,3-Dipolar Cycloaddition of 2,6-Dibenzylidenecyclohexanone
Hassan A. Albar,* John Fawcett, and D. R. Russell
*Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah 21413 P.O.Box 9028, Saudi Arabia
Abstract
2,6-Dibenzylidenecyclohexanone (1), 5-benzylidene-1-(2-alkyl-3,4-dihydro-4-oxoquinazolin-3-yl)-4-oxo-2-phenyl-1-azaspiro[2,5]octane (3) and 7-benzylidene-1,3,4-triphenyl-6-oxo-1,2-diazaspiro[4,5]decane (10) were aziridinated using 3-acetoxyamino-2-alkylquinazolin-4(3H)-ones (2a-c) to form 1,6-di-(2-alkyl-3,4-dihydro-4-oxoquinazolin-3-yl)-4-oxo-2,7-diphenyl-1,6-diazadispiro[2,1,2,3]decane (4a-c) and 8-(2-alkyl-3,4-dihydro-4-oxoquinazolin-3-yl)-1,3,4,9-tetraphenyl-6-oxo-1,2,8-triazadispiro[2,1,4,3]dodecane derivatives (9a) and (9b) as single stereoisomers. The stereostructures of 3a and 9a were confirmed by X-Ray crystallography.
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■ Synthesis of Methyl 2-Acetylamino-5-(1,3-dithian-2-yl)thiazole-4-carboxylate
Lidia Feliu, Wadi Ajana, John A. Joule, Francisco López-Calahorra, and Mercedes Alvarez*
*Laboratory of Organic Chemistry, Faculty of Pharmacy, University of Barcelona, Av. de Joan XXIII, s/n, 08028 Barcelona, Spain
Abstract
The synthesis of methyl 2-acetylamino-5-(1,3-dithian-2-yl)thiazole-4-carboxylate (4) by formylation of a 4-substituted thiazole and then reaction with 1,3-propanedithiol are described. The utility of different ortho-directing groups (ODGs) for the lithiation of the thiazole 4-position has been studied
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■ Reactivity of 1-Aryl-4-dimethylamino-2-phenyl-1,3-diaza-1,3-butadienes towards Dienophiles, 1,3-Dipoles and Carbanions
Piero Dalla Croce,* Raffaella Ferraccioli, and Concetta La Rosa
*Dipartimento di Chimica Organica e Industriale, Centro C. N. R., V. Venezian 21 I-20133 Milano, Italy
Abstract
The reactivity of 1-aryl-4-dimethylamino-2-phenyl-1,3-diaza-1,3-butadienes (1) towards dienophiles, 1,3-dipoles and C-nucleophiles was investigated. N-Phenylmethylene-benzenesulfonamide (2), phenylisocyanate (6), C,N-diphenylnitrone (9) and acylacetates (10) reacted with 1 giving quinazoline or pyrimidine derivatives. The possible mechanisms involved in products formation are discussed.
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■ An Efficient Synthesis for Pyrimido[4',5':4,5]thieno[2,3-c]pyridazine Derivatives via Intramolecular Aza-Wittig Reaction-Heterocyclization Strategy
José M. Quintela,* Rafael Alvarez-Sarandés, M. Carmen Veiga, and Carlos Peinador
*Departamento de Química Fundamental Industrial, Facultad de Ciencias, Universidad de La Coruña, Campus de A Zapateria, s/n, E-15071, La Coruña, Spain
Abstract
A ready one-pot preparation for substituted pyrimidothienopyridazines is reported. Aza-Wittig reaction of iminophosphorane (3), derived from ethyl 5-amino-3,4-diphenylthieno[2,3-c]pyridazine-6-carboxylate (2), with isocyanates, followed by heterocyclization on addition of amines provided a novel synthetic route to the functionalized pyrimido[4’,5’;4,5]thieno[2,3-c]pyridazines (6). The guanidine-type intermediate compounds (5) derived from addition of amines to the carbodiimides (4) could be isolated and characterized, thus confirming the suggest reaction pathway.
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■ Unexpected Rearrangement of 2-Carboxymethyleneindan-1-one Arylhydrazones to Spiro[indan-2,4'-quinoline] Keto Lactams
Fausta Palluotto, Giuliano Delle Monache, Giovanni Casini, and Francesco Campagna*
*Dipartimento di Farmaco Chimico, Università degli Studi di Bari, Via E. Orabona 4, 70125 Bari, Italy
Abstract
The reaction of 1-keto-2-indanylacetic acid (3) with substituted phenylhydrazine hydrochlorides (4) yielded the spiro[indan-2,4’-quinoline] keto lactams (6). The structures of compounds (6) were assigned on the basis of 1H- and 13C-NMR analyses. A possible reaction mechanism is proposed.
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■ Synthesis of Aspirochlorine Precursors
Kuniaki Itoh,* Makoto Kasami, Rintaro Yamada, Toshiaki Kubo, Masahiro Honda, and Akira Sera
*Department of Chemistry, Faculty of Science, Kobe University, Nada-Ku, Kobe 6557-8501, Japan
Abstract
Synthesis of key precursors of aspirochlorine (1) and related compounds has been achived in 5 steps from 1,4-diacetyl-2,5-piperazinedione (2). MCPBA mediated oxidative cyclization of 1-acetyl-3-salicylidene-2,5-piperazinedione (4) yielded a spiro 3H-benzofuranol derivatives (6) stereoselectively. Bromination of 6 by a 2-fluoropyridinium salt and sodium bromide, followded by NBS treatment yielded dibromide mixtures (8). Conversion of produced dibromides (8) to dithioacetates (9) by potassium thioacetate afforded all of four possible diastereomers. The ratio of the diastereomers was found to be solvent dependent.
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■ Synthetic Approaches to Benzofuran Containing Insulin Sensitivity Enhancer Compounds for Treatment of Type II Diabetes
Bret E. Huff, Cindy L. Leffelman, Michael E. LeTourneau, Kevin A. Sullivan, Jeffrey A. Ward, and John R. Stille*
*Chemical Process Research and Development Division, Lilly Reserach Laboratories, Eli Lilly & Company, Lilly Corporate Center, Indianapaolis, IN 46285-4813, U.S.A.
Abstract
The search for Insulin Sensitivity Enhancer (ISE) compounds, for potential use in the treatment of Type II diabetes, has led to the synthesis of compounds that contain a benzofuran spacer between an aryloyl substituent and a 2,4-thiazolidinedione pharmacophore. Sequential combination of haloacetyl aryl substrates with 5-formylsalicylaldehyde gave the desired 2-aryloyl-5-formylbenzofuran intermediates. A related class of compounds, those with a methylene tether between the aromatic moiety and the benzofuran spacer, were also prepared through this strategy.
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■ Synthesis of Enantiomerically Pure Monosubstituted 1,2λ5-Oxaphospholanes. Synthesis of Z-Homoallylic Alcohls
Kentaro Okuma,* Yu-ichiro Tanaka, Syun-ichi Hirabayashi, Kosei Shioji, and Haruo Matsuyama
*Department of Chemistry, Faculty of Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
Abstract
Enantiomerically pure 5-monosubstituted 1,2λ5-oxaphospholanes were synthesized by the reaction of sodium hydride with enantiomerically pure 3-hydroxyalkyltriphenylphosphonium salts. The reaction of 1,2λ5-oxaphospholanes with aldehydes afforded Z-rich homoallylic alcohols in nearly quantitative yields. The E:Z ratio of the products was in the range of 11:89-34:66.
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■ Structural Elucidation of Isomeric Methyl (E)-3-[5-Aminobenzotriazol-1(2)(3)-yl]propenoates by NMR Spectroscopy
Antonio Carta, Paolo Sanna,* and Henriette Molinari
*Instituto di Chimica Farmaceutica e Tossicologica, University of Sassari, Via Muroni 23/a, 07100 Sassari, Italy
Abstract
Revised attribution of the structure to three isomers of methyl (E)-3-[5-aminobenzotriazol-1(2)(3)-yl]propenoate ((E)-2, 3 and 4), using combined experiments of mono- and two-dimensional NMR spectroscopy, is reported.
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■ Synthesis and Conformational Study of Indolo[2,3-a]quinolizidine-3-ethan-1'-ols: Intermediates for the Synthesis of Deplancheine and Flavopereirine
Mauri Lounasmaa,* Kimmo Karinen, and Arto Tolvanen
*Laboratory for Organic and Bioorganic Chemistry, Technical University of Helsinki, P.O. Box 6100, FIN-02150 HUT Espoo, Finland
Abstract
The synthesis and stereostructures of all four indolo[2,3-a]quinolizidine-3-ethan-1’-ols are described. The two alcohols with an axial side chain exist principally in the conformation where the C/D ring junction is trans, which is favoured by an intramolecular hydrogen bond between the hydroxyl group and the Nb-atom. Dehydration of the four alcohols with P2O5 in each case led to a mixture consisting of E-deplancheine and Z-deplancheine. The three side products were two 3-vinyl isomers, one of which can be converted to deplancheine via double bond isomerization, and 3-ethyl-1,4,6,7,12,12b-hexahydroindolo[2,3-a]quinolizine, which is a precursor of flavopereirine.
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■ Synthesis and Reaction of N-Trimethylsilylmethylisothiourea Derivatives as Aminonitrile Ylide Equivalents
Makoto Oba, Masahiro Yoshihara, and Kozaburo Nishiyama*
*Department of Material Science and Technology, Tokai University, 317, Nishino, Numazu, Shizuoka 410-0395, Japan
Abstract
N-Trimethylsilylmethylisothiourea derivatives (2-5) prepared by an addition of an amine toward trimethylsilylmethyl isothiocyanate (1) followed by S-methylation were found to react with various carbonyl compounds in the presence of fluoride ion to afford the oxazoline derivatives (6-9), the formal [3+2] cycloadducts, in fair yields, in which the isothiourea derivatives served as aminonitrile ylide equivalents.
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■ Structures of Neoacrimarines-F and -G, Two New Acridone-Coumarin Dimers from Citrus Plants
Yuko Takemura, Junko Kuwahara, Motoharu Ju-ichi,* Mitsuo Omura, Chihiro Ito, and Hiroshi Furukawa
*Faculty of Pharmaceutical Sciences, Mukogawa-Women's University, 11-68 Koushien Kyuban-Cho, Nishinomiya, Hyogo 663-8179, Japan
Abstract
Two new neoacrimarines-F and -G were isolated from Yalaha (Citrus paradisi Macf. x C. tangerina Hort ex Tanaka) and Marsh grapefruit (C. paradisi Macf.), respectively. Their structures wre determined through extensive use of NMR spectroscopy.