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. 31, No. 5, 1990
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■ Flash Vaccum Pyrolysis of Pyridine N-Oxides
Takashi Itoh, Akio Ohsawa,* Yoshikuni Itoh, and Hiroshi Igeta
*School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
Abstract
Pyridine N-oxide was pyrolysed under flash vacuum pyrolysis conditions to afford pyridine, pyrrole, 2-pyridone, 2-cyanomethylpyridine, and bipyridyls. Phenylpyridine N-oxides gave cyanonaphthalenes and naphthalene other than the above mentioned products. Pyrolysis of 2,6-disubstituted pyridine N-oxides provided the products which were supposed to be derived from the intramolecular oxygen migration.
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■ New Stereospecific Ring Closure Reaction of 1,2-Diaxial Azido Alcohols
Csaba Simon and Sándor Makleit
*Department of Organic Chemistry, Lajos Kossuth University, P.O.Box 20, H-4010 Debrecen, Hungary
Abstract
7β-Azidoneopine possessing 1,2-trans-pseudodiaxial azido and hydroxyl groups gave thiazolidinethione derivative in the presence of triphenylphosphine (TPP) and CS2 which is a new stereospecific ring closure reaction. This procedure can be used on a carbohydrate model as well. This procedure can be used on a carbohydrate model as well. The reaction mechanism is also discussed.
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■ Novel 2-Methyl-1-oxacephalosporins 1. Synthesis of 2-Methyl-3-nor-1-oxacephem Nucleus
Tsuneo Okonogi,* Seiji Shibahara, Yasushi Murai, Sigeharu Inouye, Shinichi Kondo, and Burton G. Christensen
*Pharmaceutical Research Center, Meiji Seika Kaisha Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama 222-8567, Japan
Abstract
The 2α- and 2β-methyl-1-oxacephems were synthesized stereoselectively starting from (3R,4S)-oxazolinoazetidinone by reaction with chiral alcohols followed by intramolecular carbene insertion of α-diazo-β-keto intermediates.
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■ Novel 2-Methyl-1-oxacephalosporins 2. Synthesis of 3-Substituted 2-Methyl-1-oxacephem Nucleus
Tsuneo Okonogi,* Seiji Shibahara, Yasushi Murai, Sigeharu Inouye, Shinichi Kondo, and Burton G. Christensen
*Pharmaceutical Research Center, Meiji Seika Kaisha Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama 222-8567, Japan
Abstract
The stereoselective syntheses of 3-substituted 2α- and 2β-methyl-1-oxacephems have been achiebed through the intramolecular Wittig condensations of 4-(1-methylpropoxy)azetidinones.
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■ An Interesting Regioselectivity of Palladation for Bromoindole Derivatives: A Convenient One-Step Synthesis of 4-Bromodehydrotryptophan Derivatives
Yuusaku Yokoyama, Makio Takahashi, Yukari Kohno, Kazutaka Kataoka, Yasuko Fujikawa, and Yasuoki Murakami*
*School of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan
Abstract
N’-Protected-N-tosyl-4- or 5-bromodehydrotryptophan (3) was obtained by the regioselective vinylation of N-tosyl-4- or 5-bromoindole (1) with N-protected dehydroalanine methyl ester (2) by the use of stoichiometric amount of PdCl2. On the other hand, the same reaction of 4-bromoindole (1b) under catalytic conditions gave the 4-vinylated product (4).
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■ The Synthesis of a Rotationally Restricted Phenolic Analog of 5-Methoxy-3-(1,2,5,6-tetrahydropyrid-4-yl)indole (RU-24,969)
John E. Macor* and Michael E. Newman
*Department of Medical Chemistry, Central Research Division, Pfizer Inc., Groton, Connecticut 06355, U.S.A.
Abstract
Pyrrolo[3,2-b]pyrid-5-one represents a rotationally restricted phenolic analog of 5-hydroxyindole. The synthesis of the rotationally restricted phenolic analog of the serotonin agonist, 5-methoxy-3-(1,2,5,6-tetrahydropyrid-4-yl)indole (RU-24,969), is presented. Protection of the 2-pyridone in this synthesis was achieved using its t-butyl ether.
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■ Regioseletivity in the 3,5-Dialkylation of 3,5-Dimethyl-4-(4-methylcyclohexen-1-yl)isoxazole
Cecilia Polo, Vicente Ramos, Tomás Torroba,* Ricardo Bossio, Stefano Marcaccini, and Roberto Pepino
*Departamento de Química Orgánica, Facultad de Veterinaria, Universidad de Extremadura, 10071 Cáceres, Spain
Abstract
3,5-Dimethyl-4-(4-methylcyclohexen-1-yl)isoxazole reacts with β-methallyl chloride and either lithium isopropylcyclohexylamide or n-butyhyllithium in THF to afford the three alkylation products II, III, IV, in yields controlled by the ratio of isoxazole:base:halide.
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■ A Facile Synthesis of Bromo-2-alkoxypyridines
Min-Jen Shiao* and Kai-Yih Tarng
*Institutue of Chemistry, Academia Sinica, 128, Yan-Chiu-Yuan Road, Sec II, Nankang, Taipei,11529, Taiwan, R.O.C.
Abstract
Several bromo-2-methoxypyridines 2a-2e and bromo-2-benzyloxypyridines 2a’-2e’ were synthesized by the reaction of bromo-substituted 2-pyridones 1 which were reacted with alkyl halides in the presence of silver carbonate in benzene.
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■ Triazolium Salts, II: Derivatives of 4,5-Dihydro-5,5-dimethyl-1,2,4-triazol-3-one
Joachim G. Schantl,* Norbert Lanznaster, and Hubert Gstach
*Institut für Organische und Pharmazeutisch Chemie, Universität Innsbruck, Innrain 52, A-6020 Innsbruck, Austria
Abstract
The title compound 1a was converted into novel N-4-substituted derivatives. Catalytic hydrogenation of 1a yielded the triazolidin-3-one 3, the cyclotautomer of acetone semicarbazone 4. Meerwein salts alkylated the diazene function of 1a at N-2 affording the triazolium salts 5.
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■ Triazolium Salts, III: 1-(1,1-dimethylethyl)-4,5-dihydro-3,3-dimethyl-5-oxo-3H-1,2,4-triazolium Chloride
Joachim G. Schantl,* Norbert Lanznaster, and Hubert Gstach
*Institut für Organische und Pharmazeutisch Chemie, Universität Innsbruck, Innrain 52, A-6020 Innsbruck, Austria
Abstract
The cycloaddition reaction of acetone t-butylhydrazone (6) with cyanic acid yielded the 1,2,4-triazolidin-3-one 1c, subsequent oxidative ring-opening afforded the t-butylazoalkyl isocyanate 3c. Derivatization of the isocyanate function of 3c furnished the carbamic acid derivatives 7-10. Reactions involving both geminal functional groups of 3c led to the heterocycles 11,12, and the title compound 4c; some properties and reactions of the triazolium salt 4c are described.
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■ Pomacerone, a Furanoiud Triterpene from Phellinus pomaceus
Antonio G. González, Jaime Bermejo,* M. Jesús Mediavilla, and F. Javier Toledo
*Centro de Productos Naturales Orgánicos "Antonio González", Universidad de La Laguna, Avda. Astrofísico Franciso Sánchez, 2, 38206- La Laguna, Tenerife, Spain
Abstract
The structure of a new furanoid triterpene was determined by a combination of chemical and physical methods as 23,26-dioxo-lanosta-8(9),23,25-trien-3,22-dione (pomacerone) (3).
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■ Synthesis of the Alkaloids (±)-Normalindine and (±)-Norisomalindine
Bhim C. Maiti, Venkatachalam S. Giri, and Satyesh C. Pakrashi*
*Indian Institute of Chemical Biology, Calcutta-700 032, India
Abstract
The alkaloids normalidine (3) and norisomalindine (4) have been synthesized via the β-carbolinium slat (7) by pivaloyl chloride induced cyclization and subsequent reduction with sodium cyanoborohydride.
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■ Synthesis of Isoxazolylphosphazene
Mark S. Munsey and Nicholas R. Natale*
*Department of Chemistry, University of Idaho, 301 Renfrew Hall, Moscow, ID 83844-2343, U.S.A.
Abstract
The reaction of phosphonitrilic dichloride cyclic trimer (1) with 4-hydroxymethyl-3,5-disubstituted isoxazoles leads to incomplete substitution, and forcing condtitions gave rise to fragmentation to the corresponding 4-chloromethylisoxazole derivatives. Two carbon homologation of the C-4 isoxazole moiety, followed by reaction with (1) produced the hexakis-substitution product (9). Preliminary studies indicate that (9) functions as ligand in complexes with Co(II), Cr(III) and Mn(III).
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■ Reinvestigation of the Reported Synthesis of Naphtho[2’,1’-4,5]thiazolo[2,3-c][1,2,4]triazepines
Shiv P. Singh* and Devinder Kumar
*Department of Chemistry, Kurukshetra University, Kurukshetra-132119, Haryana, India
Abstract
The reaction of 2-hydrazinonaptho[2,1-d]thiazole with 1,3-diketones affords 2-pyrazolylnaphtho[2,1-d]thiazoles rather than naphtho[2’,1’-4,5]thiazolo[2,3-c][1,2,4]triazepines as previously reported. The structures assignment is based on nmr (1H and 13C) and mass spectral data and an unambigious synthesis.
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■ Murisolin: A New Cytotoxic Mono-tetrahydrofuran-γ-lactone from Annona muricata
Saw Hla Myint, Alan Laurens, Reynald Hocquemiller, André Cavé, Daniel Davoust, and Diego Cortes*
*Laboratoire de Pharmacognosie, Faculté de Médecine et Pharmacie, Université de Rouen, 76800 Saint Etienne du Rouvary, France
Abstract
Using cytotoxicity as a bioassay guide led to the isolation of a new active acetogenin from the used of Annona muricata. Murisolin, 1 is the first example of a mono-tetrahydrofuran-γ-lactone acetogenin with only three hydroxyl groups. Its structure was characterised by mass spectrometry and 2D homonuclear and heteronuclear correlations nmr spectroscopy. The relative stereochemistry of four of its six chiral centers was established by 1H-nmr comparative spectral studies between the murisolin triacetate and some bistetrahydrofuran acetogenin acetates.
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■ A Synthesis of 1,2,4-Triazolo[1,5-f]phenanthridines by Rearrangements of 1,2,5-Oxadiazoles Involving an NCN Sequence with the Imine Nitrogen in an Aromatic Heterocyclic Ring
Giuseppe Cusmano, Gabriella Macaluso, Michelangelo Gruttadauria, and Silvestre Buscemi
*Dipartimento di Chimica Organica, Università digli Studi di Palermo, Via Archirafi 20 90123 Palermo, Italy
Abstract
A synthetic pathway to 1,2,4-triazolo[1,5-f]phenanthridine system by a base catalyzed rearrangement of 3-(6-phenanthridine)amino-1,2,5-oxadiazoles (5a,b) has been investigated. This ring transformation is the first example of the applicability of the mononuclear heterocyclic rearrangement involving an NCN sequence to the synthesis of bridged nitrogen system.
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■ Artonins E and F, Two New Prenylflavones from the Bark of Artocarpus communis Forst.
Yoshio Hano, Yukiko Yamagami, Miki Kobayashi, Ryoko Isohata, and Taro Nomura*
*Faculty of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan
Abstract
Two new prenylflavones, artonins E (1) and F (2), were isolated from the bark of Artocarpus communis Forst. (Moraceae), along with a known compound, cycloartobiloxanthone (3). The structures of artonins E and F were shown to be 1 and 2, respectively, on the basis of spectroscopic data.
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■ Synthesis of Imdazo[4,5-d]imidazole-2,5-dithiones by Crisscross Addition Reaction of 1,4-Diaza-1,3-dienes to Isothiocyanatorimethylsilane
Masahiko Takahashi* and Shinji Miyadai
*Department of Industrial Chemistry, Faculty of Engineering, Ibaraki University, 4-12-1 Nakanarusawamachi, Hitachi, Ibaraki 316-8511, Japan
Abstract
Treatment of 1,4-disubstituted 1,4-diaza-1,3-dienes with isothiocyanatotrimethylsilane yielded crisscross addition products, 1,4-disubstituted tetrahydroimidazo[4,5-d]imidazole-2,5-dithiones.
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■ The C-O Bond Cleavage of Cyclic Ethers with Tris(phenylseleno)borane-Lewis Acid
Tadashi Kataoka, Mitsuhiro Yoshimatsu, Hiroshi Shimizu, Yoshitaka Kawase, and Mikio Hori*
*Department of Pharmacognosy, Gifu College of Pharmacy, 6-1 Mitahora-higashi 5-chome, Gifu 502-8585, Japan
Abstract
Tris(phenylseleno)borane (1) has a hard boron element and a soft selenium element, and therefore it was expected that 1 cleaves the C-O bond. Tetrahydrofuran and tetrahydropyran were cleaved with 1 in the presence of zinc iodide to produce the δ- and ε-phenylseleno alcohols (7 and 8). The C(5)-O bond of 2-methyltetrahydrofuran (5) was regioselectively cleaved with 1 and a catalytic amount of tin(IV) chloride to afford the δ-phenylseleno alcohol (12). The selenoborane (1) was a weak reagent for the C-O bond-cleavage and cleaved only cyclic ethers selectively.
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■ Reaction of Methoxy-N-heteroarmatics with Phenylacetonitrile under Basic Conditions
Hiroshi Yamanaka* and Setsuya Ohba
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
The monomethoxyl derivatives of various π-elelctron-deficient N-heteroaromatics with phenylacetonitrile in tetrahydrofuran in the presence of sodium hydride to give α-phenyl-N-heteroareneacetonitriles in the yields ranging from 45 to 78%. On the contrary, the reaction of these methoxyl derivatives wit ethyl cyanoacetate or malononitrile under similar conditions was restricted within narrow limits. The synthesis of benzoyl-N-heteroaromatics by the air-oxidation of α-phenyl-N-heteroareneacetonitriles was described additionally.
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■ Intramolecular Cyclization of Enaminones Involving Arylpalladium Complexes. Synthesis of 4-Oxo-1,2,3,4-tetrahydro-β-carbolines
Ling-Ching Chen* and Shyh-Chyun Yang
*Graduate Institute of Pharmaceutical Sciences, Kaohsiung Medical College, 100 Shih Chuen 1st Rd., Kaohsiung 80708, Taiwan, R.O.C.
Abstract
The synthesis of 4-oxo-1,2,3,4-tetrahydro-β-carbolines from enaminones derived from 1-benzylpiperidine-3,5-ione is described. The reaction proceeds by the intramolecular cyclization of enaminones involving arylpalladium complexes.
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■ A Facile Conversion of Natural (R)-Mevalonolactone into a Vitamin E Key Intermediate
Seiichi Takano,* Youichi Shimazaki, and Kunio Ogasawara
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
Natural (R)-mevalonolactone (1) produced by fermentation has been facilely converted into a vitamin E key synthetic intermediate (2).
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■ Pyrimidine N-Oxides: Syntheses, Structures, and Chemical Properties
Hiroshi Yamanaka,* Takao Sakamoto, and Setsuko Niitsuma
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
The synthesis and reactions of pyrimidine N-oxides are reviewed. Pyrimidines having alkyl, aryl, and alkoxyl groups are convertible to their mono-N-oxides by N-oxidation with an organic peroxy acid. The position of the N-oxide group can be elucidated by phsical methods. Pyrimidine N-oxides are highly reactive to various nucleophilic reagents owing to their π-deficient character. The reactivity of a methyl group enhanced by introducing an N-oxide group and the characteristic ring-cleavage of N-oxides are also described.