HETEROCYCLES

■ The Photochemistry of Pyridothiazoles

Shigeru Ito, Minoru Maeda, and Masaharu Kojima*

*Faculty of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan

Abstract

Irradiation of tetramethyl 1-phenylpyrido[2,1-b]thiazole-2,3,4,4a-tetracarboxylate (1) gave the corresponding 1H-isomer (2) and presumable 4-thia-1-azabicyclo[3,2,2]nona-2,6,8-triene derivative (3) in low yields, while that of tetramethyl 6-phenyl-1H-pyrido[2,1-b]thiazole-2,3,4,4a-tetracarboxylate (4) resulted in the formation of pyrrolo[2,1-b]thiazole (5) and tetramethyl pyridine-2,3,4,5-tetracarboxylate (6).

■ The Synthesis of Sulfomycinine

Hiroshi Abe, Tetsuo Takaishi, Yukio Ito, and Tomoharu Okuda*

*Research Administration Division, Tanabe Seiyaku Co.Ltd., 2-2-50, Kawagishi, Toda, Saitama 335-8505, Japan

Abstract

The structure and configuration of sulfomycinine, one of the acid degradation products of an antibiotic sulfomycin I, was communicated previously. In this communication, synthesis of sulfomycinine is reported.

■ Newer Method in the Total Syntheses of Natural Products

Tetsuji Kametani* and Keiichiro Fukumoto

*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan

Abstract

Total syntheses of natural products, such as isoquinoline, indole and diterpene alkaloids, terpenes and a steroidal compound by phenolic oxidation, Pschorr reaction, photolytic reaction, benzyne reaction and thermolysis of benzocyclobutene derivatives, which had been developed mainly in this laboratory, are described.

■ Sesquiterpene Lactones and Heterocyclic Compounds of Bryophyta

Yoshinori Asakawa and Tsunematsu Takemoto*

*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan

Abstract

A review of some recent works on the chemical constituents of bryophytes is presented.

■ A Brief Review of Nucleoside Antibiotics

Shoshiro Nakamura* and Hisao Kondo

*Institute of Pharamceutical Sciences, Faculty of Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan

Abstract

Nucleoside antibiotic-producing organisms, extraction methods, biological activities, UV absorption maxima and chemical structures of the nucleoside antibiotics are briefly reviewed in three summary tables. These tables can be conveniently referred to, when screening new metabolites, to determine chemical structures and to study structure-activity relationships of nucleoside antibiotics. Nucleoside antibiotics are described in order of the aglycone nuclei, namely purine (I-XVIII), pyrrolo[2,3-d]pyrimidine (XIX-XXI), pyrazolo[4,3-d]pyrimidine (XXII-XXIV), pyrimidine (XXV-LVI, LIX, LX), s-triazine (LVII), s-dihydrotriazine (LVIII), imidazole (LXI), pyrazole (LXII), maleimide (LXIII) and 1,3-oxazine (LXIV) in the tables. References of each nucleoside antibiotic are numbered in Table I.

■ Reaction of Carbenes with Pyrimidines and Isoquinoline Derivatives. Approaches to the Synthesis of Modified Nucleosides and Alkaloids

Upendra K. Pandit*

*Organic Chemistry Laboratory, University of Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands

Abstract

Reactions of carbenes¹ with the olefinic function of heterocyclic systems is of potential interest in the derivitisation and ring-expansion of the heterocycles². In the case of nitrogen heterocycles, the course of the reaction is expected to be significantly influenced by (a) the basicity of the nitrogen atom (s) and (b) their location with respect to the double bond, in addition to other factors. Of particular interest is the reaction (with carbenes) of nitrogen heterocycles which contain a potential enamine functionality. Recent developments in this specific area are the subject of the present discussion.

■ Synthesis of Pumiliotoxin C. A Toxic Alkaloid from Central American Arrow Poison Frog, Dendrobates pumilio and D. auratus

Yasuo Inubushi* and Toshiro Ibuka

*Faculty of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida-shimoadachi-machi, Sakyo-ku, Kyoto 606-8501, Japan

■ Free Radical Telomerization of Vinylene Carbonate (1,3-Dioxol-2-one) with Polyhalomethanes — Chemistry and Synthetic Applications of Telomers —

Takehisa Kunieda* and Takeo Takizawa

*Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-hon-machi, Kumamoto 862-0973, Japan

Abstract

Free-radical telomerization of vinylene carbonate (1,3-dioxol-2-one) in the medium of polyhalomethanes proceeds smoothly to result in the stereoselective formation of type 2 telomers, among which lower products (n<3) are obtainable in high stereohomogeneity and may serve as versatile intermediates for the synthesis of polyalcohols including carbohydrates and related compounds of biological significance. Preparation and chemistry of the title telomers, and their potential as synthetic intermediates are surveyed from a preparative point of view.

■ Synthesis and Reaction of 2-Allylindoles

Ryuji Tachikawa, Atsusuke Terada,* Kuniyuki Tomita, and Teiki Iwaoka

*Central Research Laboratories, Sankyo Co.,Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140 Japan

■ Recent Advances in the Synthesis of 7-Methoxycephalosporins (Cephamycins)

Tetsuo Hiraoka,* Yukio Sugimura, Tokio Saito, and Takeo Kobayashi

*Medicinal Chemistry Research Laboratories, Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan

Abstract

The various methods for introduction of a methoxy group at the seven posion of cephalosporin nucleus are reviewed based on our recent progress.

■ Oxidation of Indoles with Triplet Oxygen

Tohru Hino* and Masako Nakagawa

*Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan

Abstract

Autoxidation of indole derivatives provides 3-hydroperoxyindolenines as the initial product which collapse to a variety of products depending upon the structures and reaction conditions. The oxidation is discussed under the following headings.

■ Selective Cleavage of Glucuronide Linkage in Oligoglycoside

Isao Kitagawa* and Masayuki Yoshikawa

*Faculty of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Toyonaka, Osaka 560-0043, Japan

Abstract

Selective cleavage of a specific glycoside linkage in oligoglycoside (e.g. saponin) is considered to be useful especially for structure elucidation of the carbohydrate portion in the oligoglycoside. This article summarizes the recent investigations on the selective cleavage methods for the glucuronide linkage in oligoglycoside (glucuronide-saponin) which have been undertaken in the authors’laboratory.

■ Studies in Indole Alklaoids Synthesis. A General Synthetic Route to 2-Acylindole Alkaloids and Related Compounds

James P. Kutney*

*Department of Chemisry, University of British Columbia, Vancouver 8, V5T 1W5, Canada

Abstract

A general synthetic route to 2-acylindole alkaloids has been developed. The readily available starting material, L(-)-tryptophan, is elaborated by standard methods to the β-carboline derivative 7, and the latter upon condensation with 3-methylene-pentan-2-one affords the tetracyclic ketones A-D, all of which are employed in the subsequent synthetic steps. Base-catalyzed cyclization of ketone D affords the nitriles 21 and 22 bearing the skeletal features of the sarpagine family and these compounds upon ring-opening with cyanogen bromide, convert to the desired intermediates 23, 24 and 25. Final elaboration of these intermediates to the 2-acylindole system completes the first syntheses of epi-dregamine and dregamine.