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. 23, No. 9, 1985
Published online:
■ The Synthesis of 2’S,3R- and 2’S,3S-Hexahydronicotine
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
The reduction of 1-benzylnicotinium bromide(4) with NaBH4 led to 1-benzyl-1,2,5,6-tetrahydronicotine(5), and the catalytic reduction of 5 over Raney nickel gave 2’S,3R- and 2’S,3S-1-benzylhexahydronicotine(6a,6b) in the ratio of 4 : 1 at room temperature. The debenzylations of 6a and 6b were carried out by the catalytic reduction over palladium on charcoal to give 2’S,3R- and 2’S,3S-hexahydronicotine(2a,2b), respectively. The configurations of 2a and 2b were determined by NMR spectra.
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■ Reaction of 4-Thioxo-1,3-benzothiazines with Amidrazones: Synthesis of 1,2,4-Triazolo[1,5-c]quinazoline Derivatives
Pedro Molina,* Antonio Arques, Inmaculada Cartagena, and Maris Victoria Valcarcel
*Departmento de Química Orgánica, Facultad de Ciencias, Universidad de Murcia, 30071 Murcia, Spain
Abstract
4-Aryl-4-thioxo-1,3-benzothiazines react with unsubstituted amidrazones to give the corresponding amidinoquinazolinthiones which by action of methyl iodide cyclize to 2,5-diaryl-1,2,4-triazolo[1,5-c]quinazolines. Reaction of amidinoquinazolinthiones with hydrochloric acid leads to 2,5-diarylthiadiazoles.
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■ New Methods and Reagents in Organic Synthesis. 52. Lithium Trimethylsilyldiazomethane: A New Synthon for the Preparation of 1-Substituted 5-Hydroxy-1,2,3-triazoles from Isocyanates
Toyohiko Aoyama,* Mototsugu Kabeya, Atsuko Fukushima, and Takayuki Shioiri
*Faculty of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
Abstract
Lithium trimethylsilyldiazomethane reacts smoothly with isocyanates to give 1-substituted 5-hydroxy-1,2,3-triazoles in good yields.
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■ New Method and Reagents in Organic Synthesis. 53. Lithium Trimethylsilyldiazomethane: a New Synthon for the Preparation of 2-Amino-1,3,4-thiadiazoles from Isothiocyanates
Toyohiko Aoyama,* Mototsugu Kabeya, Atsuko Fukushima, and Takayuki Shioiri
*Faculty of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
Abstract
Lithium trimethylsilyldiazomethane reacts smoothly with isothiocyanates in diethyl ether to give 2-amino-1,3,4-thiadiazoles in good yields.
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■ New Methods and Reagents in Organic Synthesis. 54. Lithium Trimethylsilylydiazomethane: A New Synthon for the Preparation of 1-Substituted 5-Alkylthio-1,2,3-triazoles from Isothiocyanates
Toyohiko Aoyama,* Mototsugu Kabeya, and Takayuki Shioiri
*Faculty of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
Abstract
Lithium trimethylsilyldiazomethane (1) reacts smoothly with isothiocyanates in tetrahydrofuran to give 1-substituted 4-trimethylsilyl-5-alkylthio-1,2,3-triazoles (2) after quenching with alkyl halides. Desilylation of 2 is easily achieved with 10% aqueous potassium hydroxide in methanol to afford 1-substituted 5-alkylthio-1,2,3-triazoles (3).
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■ A Simple and Regioselective Preparation of 2- or 3-Substituted Quinoline Derivatives via Dialkylquinolylboranes
Minoru Ishikura, Izumi Oda, and Masanao Terashima*
*Faculty of Pharmaceutical Scicences, Higashinihonngakuen University, 1757 Kanazawa, Toubetu-cho, Ishikari-gun, Hokkaodo 061-0212, Japan
Abstract
Various quinoline derivatives possessing a substituent at the 2- or 3-position were prepared by the reaction of dialkylquinolylboranes and organic bromides in the presence of a palladium catalyst.
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■ Synthesis of 1,2,3,4,4a,5,10,10a-Octahydro-7-hydroxy-2,4a,5-trimethyl-1,5-ethanobenao[g]quinoline: Bridged Benzomorophan with Antagonist Activity
Mikio Hori,* Tadashi Kataoka, Hiroshi Shimizu, Eiji Imai, and Norihiro Kawamura
*Department of Pharmacognosy, Gifu College of Pharmacy, 6-1 Mitahora-higashi 5-chome, Gifu 502-8585, Japan
Abstract
A synthetic approach has been made for the synthesis of 1,5-ethanobenzo[g]quinolines from 11-substituted 2,6-methano-3-benzazocine. The product showed strong antagonist activity.
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■ Reaction pf Benzo[b]thiophene-5- and 6-Methanols with n-Butyllithium. Directed Lithiation in the Benzene Ring
Peter E. Cross and Roger P. Dicknson*
*Animal Health Discovery, Pfizer Central Research, Ramsgate Road, Sandwich, Kent, CT13 9NJ, U.K.
Abstract
The preparation of 3-methylbenzo[b]thiophene-6-methanol (3) is described. Treatment of 3 with n-butyllithium followed by CO2 gave, in addition to the expected 2-carboxylic acid 2, a substantial quantity of the lactone 11 formed via lithiation at the 7-position. It was concluded that lithiation at the 7-position is favoured by a co-operarive effect of the anion of the alcohol and the ring sulphur atom, as well as the 3-methyl group which reduces the rate of lithiation at the 2-position. In the case of compounds in which the alcohol group is at the 5-position or which lack the 3-methyl group, lithiation in the benzene ring was much less favoured.
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■ Thermal Reactions of 1,4-Benzoxazine Derivtives II
Norio Kawahara,* Takako Shimamori, Tsuneo Itoh, and Haruo Ogura
*Hokkaido College of Pharmacy, 7-1 Katsuraoka-cho, Otaru 047-02, Japan
Abstract
The pyrolysis or treatment with base of aconitate derivatives (1a,c) afforded expected cyclization products (4a,c) whose structural elucidation was based on spectral data.