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. 24, No. 8, 1986
Published online:
■ The Synthesis of Bithienyls and Terthienyls by Nickel-catalyzed Coupling of Grignard Reagents
Nimal Jayasuriya and Jacques Kagan*
*Department of Chemistry, University of Illinois at Chicago, 845 West Taylor St., Chicago, IL 60607-7061, U.S.A.
Abstract
The coupling of thienyl Grignard reagents and bromothiophene derivatives in the presence of Ni(dppp)Cl2 is particularly good for linking one thiophene derivative to the beta position of another one, as illustrated by the synthesis of 2,3’- and 3,3’-bithienyl. The same procedure was used for the synthesis of 3,2’:3’,3”-, 3,2’:4’,3”-, 3,3’:4’,3”-, 2,2’:3’,3”-, and 2,2’:3’,2”-terthienyls, in yields ranging between 61 and 93%.
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■ Heteroyohimbine Alkaloid Synthesis
Reija Jokela, Tuula Taipale, Kari Ala-Kaila, and Mauri Lounasmaa*
*Laboratory for Organic and Bioorganic Chemistry, Technical University of Helsinki, P.O. Box 6100, FIN-02150 HUT, Espoo 15, Finland
Abstract
Preparation of the heteroyohimbine analogues 6 and 7 and a new short stereoselective total synthesis of (±)-3-iso-19-epiajmalicine 12 are described.
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■ A Study on the Synthesis of Carumonam Starting from an α-Amino Acid
Shohei Hashiguchi,* Yoshiharu Maeda, Shoji Kishimoto, and Michihiko Ochiai
*Chemical Development Laboratory, Takeda Chemical Industries, Ltd., 17-85 Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan
Abstract
As part of a study on the synthesis of carumonam (1), a method starting from an α-amino acid was investigated. Cycloaddition of the mixed anhydride, derived from carbobenzoxyglycine (7) and isopropyl chloroformate, with the chiral imine (11b), derived from p-chlorobenzoyloxyacetaldehyde and L-valine methyl ester, afforded a diastereomeric mixture of two cis-β-lactams (13 and 14). The desired (3S,4S)-isomer (13) was isolated preferentially from the mixture by fractional crystallization. Conversion of 13 into (3S,4S)-3-benzyloxycarbonylamino-4-carbamoyloxymethyl-2-azetidinone (3), an intermediate in preparing carumonam (1), was achieved by applying anodic oxidation to remove the N1-substituent of 13.
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■ Structures of Sanggenons E and P, Two New Diles-Alder Type Adducts from the Chinese Crude Drug "Sang-Bai-Pi" (Morus Root Bark)
Yoshio Hano, Hideaki Kohno, Shinkichi Suzuki, and Taro Nomura*
*Faculty of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan
Abstract
Two new flavanone derivatives named sanggenons E and P were isolated from the extract of the Chinese crude drug “Sang-Bai-Pi” (Japanese name “Sohakuhi”), the root bark of Morus sp. (Moraceae). The structures of sanggenons E and P were shown to be 1 and 2, respectively, on the basis of spectral evidence. Sanggenons E and P are optically active and can be regarded biogenetically as Diels-Alder type adducts of a chalcone derivative and a dehydroprenylflavanone derivative. Sanggenon P is a stereoisomer at the C-14 position on the cyclohexene ring of sanggenon E. Furthermore, it is interesting that a pair of isomers on the methylcyclohexene ring were isolated from the same crude drug.
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■ Pyrimidines. Part 57. A Versatile Synthesis of Pyrimido[4,5-d]pyrimidine-2,4,5-trione Derivatives
Kosaku Hirota,* Jiazi Huang, Hironao Sajiki, and Yoshifumi Maki
*Labolatory of Medicinal Chemistry, Gifu Pharmaceutical University, 6-1 Mitahora-higashi 5-chome, Gifu 502-8585, Japan
Abstract
Synthesis of pyrimido[4,5-d]pyrimidine derivatives (2-5) was effected by cyclization of 6-amino-5-carbamoyluracil derivatives (1) with one-carbon reagents such as dimethylformamide dimethylacetal, acid anhydrides, and N,N’-carbonyldiimidazole.
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■ Heterocyclic Studies — Part 1. Synthesis of Thieno[2,3-d]triazoles
Jan Becher,* Preben H. Olesen, and Klaus Brøndum
*Department of Chemistry, Odense University, Campusvej 55 DK-5230 Odense M., Denmark
Abstract
The thieno[2,3-d]triazole-5-carboxylic acid was synthesized from a 5-chloro-4-formyltriazole. Attempted decarboxylation led to decomposition of the ring system.
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■ Reactions of Nucleophiles with 3,4-Bis(bromomethyl)-2,5-dihydrothiophene-1,1-dioxide
Ta-shue Chou* and Su Chun Hung
*Institutue of Chemistry, Academia Sinica, 128, Yan-Chiu-Yuan Road, Sec II, Nankang, Taipei,11529, Taiwan, R.O.C.
Abstract
3,4-Bis(bromomethyl)-2,5-dihydrothiophene 1,1-dioxide was reacted with n-butylamine or sodium sulfide to give the sulfolene-fused pyrrolidine and hydrothiophene, respectively while its reaction with siloxide gave only the 1,4-elimination product. The difference in reactivity can be explained by the different nucleophilicity and basicity of these reactants.
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■ Condensed Heteroaromatic Ring Systems. XI. A Facile Synthesis of Isoquinoline N-Oxides
Takao Sakamoto, Yoshinori Kondo, Norio Miura, Kazuhiko Hayashi, and Hiroshi Yamanaka*
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
Isoquinoline 2-oxides (5a-f) were obtained by the cyclization of 2-ethynylbenzaldehyde oxime (4a-f) under basic conditions. The starting compounds (4a-f) were easily synthesized by the palladium-catalyzed reaction of 2-bromobenzaldehydes (1 and 2) with terminal acetylenes, and subsequent oximation of the resulting 2-ethynylbenzaldehydes (3a-f) .
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■ Stereoselectivity in the Synthesis of 5’-Alkylated Nicotines
Makoto Shibagaki,* Hajime Matsushita, and Hajime Kaneko
*Life Science Research Laboratory, Japan Tobacco Inc., 6-2, Umegaoka, Midori-ku, Yokohama, Kanagawa 227-8512, Japan
Abstract
In the hydride reduction of enamines formed by the alkylation of cotinine (2) with organolithium reagents, the effect of some reaction conditions on the stereochemistry of the resulting 5’-slkylnicotines was studied. The acidity of the reaction medium was the main factor determining the stereochemistry of the products.
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■ Characteristic Tautomerism and Isomerization in the Quinoxaline Chemistry
Yoshihisa Kurasawa* and Atsushi Takada
*School of Pharmaceutical Sciences, Kitasato University, Shirokane, Minato-ku, Tokyo 108-8641, Japan
Abstract
Various side-chained quinoxalines have been found to exhibit the interesting tautomeric equilibria between the enamine and methylene imine forms and between the hydrazone imine and diazenyl enamine forms by means of the various spectroscopies. Moreover, some of the quinoxaline derivatives have also been known to isomerize from one tautomer into the other stable tautomer without the tautomeric equilibria in the media. This review describes the above quinoxalines exhibiting the above tautomeric eauilibria and isomerizations.