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. 34, No. 8, 1992
Published online:
■ Mechanistic Inversion of Photoinitiated Electron Transfer Processes in Aryl Imidazolidinones
Paul H. Mazzocchi,* Nai Yong Jing, and Kazuaki Oda
*Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, U.S.A.
Abstract
Aryl imidazolidinones having o-carboxylic acid and ester containing aryl substituents were found to undergo different photochemical reactions. Although both reactions are suggested to proceed by electron transfer mechanisms, the donor and acceptor groups are interchanged.
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■ Tetra-2-thienyl- and Tetrakis(5,2’-bithiophene-2-yl)thiophenes and Selenophenes
Juzo Nakayama,* Kanji Sawada, Akihiko Ishii, and Masamatsu Hoshino
*Department of Chemistry, Faculty of Science, Saitama University, Urawa, Saitama 338, Japan
Abstract
Heating a mixture of di-2-thienylacetylene (1) and elemental selenium in benzene at 220-225 °C for 9 h in a stainless steel autoclave affords tetra-2-thienylselenophene (2b) in 65% yield. In similar ways, heating a mixture of bis(5,2’-bithiophene-2-yl)acetylene (3) and elemental sulfur or selenium gives tetrakis-(5,2’-bithiophene-2-yl)thiophene (4a) or selenophene (4b), respectively, in satisfactory yields.
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■ New Cyclization Reactions of 3-Dialkylamino-4-aminopyridines under Conditions of Nitration
Yutaka Miura,* Sakae Takaku, Yoshiharu Nawata, and Masatomo Hamana
*Production Technology Research Laboratories, Chugai Pharmaceutical Co., Ltd., Ukima 5-1-5, Kita-ku, Tokyo 115, Japan
Abstract
Treatment of 3-dialkylamiono-4-aminopyridines (1) with nitric and sulfuric acids affords imidazo[4,5-c]pyridine derivatives (2, 3 and 4) and 1,2,3-triazolo[4,5-c]pyridine 2-oxides (5) by cyclization reaction of the corresponding 4-nitroaminopyridines.
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■ New, Short Synthesis of (±)-Geissoschizine
Mauri Lounasmaa,* Reija Jokela, Jari Miettinen, and Minna Halonen
*Laboratory for Organic and Bioorganic Chemistry, Technical University of Helsinki, SF-02150 Espoo, Finland
Abstract
A short, easy way to prepare indole alkaloid (±)-geissoschizine (1) is described.
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■ Reaction of Quadricyclane with Electron Deficient p-Benzoquinones
Ken-ichi Hirao,* Tohru Yokozawa, Asami Yamashita, and Tomoki Watanabe
*Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060, Japan
Abstract
Quadicyclane reacted thermally in a [π2+σ2+σ2] manner with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and chloranil to give cyclobutanes and a spiro oxetane, respectively.
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■ Nucleophilic Fluorination of Chlorinated N-Heterocycles with Tetrabutylphosphonium Hydrogendifluoride and Dihydrogentrifluoride
Yukitaka Uchibori, Masayuki Umeno, and Hirosuke Yoshioka*
*RIKEN(Institute of Physical and Chemical Research), Wako, Saitama 351-01, Japan
Abstract
Fluorination of various chlorinated N-heterocycles with tetrabutylphosphonium hydrogendifluoride (1) or dihydrogentrifluoride (2) readily proceeded in high yields under mild conditions.
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■ A Novel Nitrile Oxide Precursor; 2-Methyl-4-nitro-5(2H)-isoxazolone
Suguru Higashida, Hiroko Nakashima, Yasuo Tohda, Keita Tani, Nagatoshi Nishiwaki, and Masahiro Ariga*
*Department of Chemistry, Osaka Kyoiku University, Minamikawabori-cho, 4-88, Tennoji-ku, Osaka 543, Japan
Abstract
2-Methyl-4-nitro-5(2H)-isoxazolone (1) was found to be a versatile precursor for a functionalized nitrile oxide by reaction with dipolarophiles giving 3-(N-methylcarbamoyl)isoxazole (2 or 3) derivatives.
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■ Enantioselective Synthesis of Indolizidine Alkaloid: A Formal Total Synthesis of (-)-Pumiliotoxin 251D
Toshio Honda,* Michiyasu Hoshi, and Masayoshi Tsubuki
*Institute of Medicinal Chemistry, Hoshi University, Ebara 2-4-41, Shinagawa-ku, Tokyo 142, Japan
Abstract
An enantioselective formal total synthesis of (-)-pumiliotoxin 251D was achieved by employing the Sharpless kinetic resolution of the 2-furylmethanol derivative (3) and a stereoselective radical cyclisation of the thiocarbonylimidazolide (10) as key steps.
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■ First Example of Intramolecular 1,3-Dipolar Cycloaddition of Non-stabilized Azomethine Ylide Generated from Tertiary Amine N-Oxide
Seiichi Takano,* Yoshiaki Sugihara, and Kunio Ogasawara
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980, Japan
Abstract
The reaction of two optically active 1-alkyl-3,4-diallyloxypyrrolidine 1-oxides, (9) and (15), under basic conditions has been examined. The 1-benzyl derivative (9), on reaction with lithium diisopropylamide, furnished a single pyrrolidine derivative (11) by intramolecular 1,3-dipolar cycloaddition of an N-benzylidene azomethine ylide (10), while the 1-methyl derivative (15) reacted with tert-butyllithium in the presence of trimethylaluminum to afford only a single 7-azabicyclo[2.2.1]heptane derivative (19) by spontaneous intramolecular 1,3-dipolar cycloaddition of the endocyclic azomethine ylide (17).
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■ Synthesis of 2,2-Dimethylbenzoxazepinones by the Schmidt Reaction of 2,2-Dimethyl-4-chromanones
Albert Lévai,* Tibor Timár, László Frank, and Sándor Hosztafi
*Department of Organic Chemistry, Lajos Kossuth University, H-4010 Debrecen, Hungary
Abstract
2,3-Dihydro-2,2-dimethyl-1,4-benzoxazepin-5(4H)-ones and 2,3-dihydro-2,2-dimethyl-1,5-benzoxazepin-4(5H)-ones have been synthesized by the Schmidt reaction of 2,2-dimethyl-4-chromanones. 2,2-Dimethylbenzoxazepinthiones have been prepared by the reaction of 2,2-dimethylbenzoxazepinones with Lawesson’s Reagent.
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■ Polyhalogenoaromatic Compounds. Part 51. Synthesis of New Heterocycles from Pentachloropyridine and 2,3,5,6-Tetrachloropyridine with Aliphatic Diamines
Luis Juliá,* Jordi Rius, and Hans Suschitzky
*Departamento de Materials Organics Halogenats, Centre d’Investigació i Desemvolupament, (CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain
Abstract
The reaction of pentachloropyridine or 2,3,5,6-tetrachloropyridine with N,N,N’,N’-tetramethylethanediamine (TMEDA) or N,N’-dimethylethanediamine (DMEDA) in dimethylformamide gave dihydropyridopyrazines (5, 9) and (6) respectively by replacement of the 2,3- or 3,4-chlorine atoms.
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■ Structure Determination of Some Pyronylpyrazoles, Correction of the Structures Described as Pyrano[4,3-c]pyrazoles
Ana Brbot-Saranovic,* Branka Katusin-Razem, and Ivan Vickovic
*Department of Chemistry and Biochemistry, Veterinary Faculty, University of Zagreb, Croatia
Abstract
Reaction of ethyl 2-hydroxy-4-(4-hydroxy-6-methyl-2-pyron-3-yl)-4-oxo-2-butenoate (1) with phenylhydrazine has been reported to give four products. The corrected structures (4 and 5) were subsequently established for two of them, which had been reported previously as 3,5-disubstituted N-phenylpyrazole-4-carboxylic acids (8, 9). Consequently, the structures of their cyclized products, instead of the reported pyrano[4,3-c]pyrazoles (10, 11) are pyronylpyrazoles (6, 7). The structure (6) was also confirmed by means of X-ray crystallography.
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■ Two New Benzofuran Derivatives, Corylifonol and Isocorylifonol from the Seeds of Psoralea corylifolia
Yun-Lian Lin and Yueh-Hsiung Kuo*
*Department of Chemistry, National Taiwan University, Taipei, Taiwan, R.O.C.
Abstract
The seeds of Psolalea corylifolia were extracted with ether and 60% EtOH, successively. The latter extract was found to contain the known constituents psoralen, angelicin, corylifolinin, bukuchiol, p-hydroxybenzoic acid, and astragalin, together with two new benzofuran derivatives, corylifonol and isocorylifonol. Their structures have been elucidated by spectral evidence and chemical transformation.
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■ [3+2] Cycloaddition of Chiral Azomethine Ylides from Aminosugar N-Oxides. Enantioselective Synthesis of 3,4-Disubstituted Pyrrolidines
Jacqueline Chastanet, Hassana Fathallah, Guillermo Negron, and Georges Roussi*
*Institut de Chimie des Substances Naturelles, C.N.R.S., 91198 Gif-sur-Yvette, France
Abstract
The base deprotonation method, applied to amino-sugar N-oxides prepared from methyl 2,3-anhydro-4,6-O-benzylidene-α-D-mannopyranoside (8) and methyl 2,3-anhydro-4,6-O-benzylidene-α-D-allopyranoside (9), allows the easy generation of complex and very reactive sugar azomethine ylides. Fair yields of the major diastereomeric pyrrolidines resulting from [3+2] cycloaddition to stilbene are thus obtained with good asymmetric induction. The easy climination of the chiral appendage as starting epoxides gives access to the enantiomerically enriched 3,4-diphenylpyrrolidines.
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■ Reaction of Ketene Dithioacetals with Thioamides. A Synthesis of Pyrimidine Derivatives
Antonio Lorente,* M. Luisa García, Misericordia Fernández, and José L. Soto
*Department of Organic Chemistry, University of Alcalá, 28871 Alcalá de Henares (Madrid), Spain
Abstract
Reaction of ketene dithioacetals with thioamides gave 5-cyano-2-methyl(or phenyl)-6-methylthio-4-thioxopyrimidines.
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■ 1,3-Cycloaddition of Benzonitrile Oxides to Diazepines. I. 1-Ethoxycarbonyl-5-methyl-1,2-diazepine
Paolo Beltrame,* Enzo Cadoni, Maria M. Carnasciali, Gioanna Gelli, Adolfo Lai, Angelo Mugnoli, and Marcella Pani
*Dipartimento di Chimica Fisica ed Elettrochimica, Università, Via Golgi 19, I-20133 Milano, Italy
Abstract
Stable aryl nitrile oxides (1a-e) and 1-ethoxycarbonyl-5-methyl-1,2-diazepine (2) undergo 1,3-cycloaddition reactions to give isomeric 1,2,4-oxadiazole (3), 4,5-dihydroisoxazole (4) and isoxazole (5) derivatives, the first one being in any case the most abundant product. Overall kinetics were measured at temperatures in the range 50-90 °C, in 1,1,2,2-tetrachloroethane and mixtures of the latter with DMF; rate coefficients for the parallel reactions were, thus, obtained. Substituent and solvent effects are discussed.
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■ Reinvestigation of Nitrosation of Methylpyridines and Their 1-Oxides and Deoxygenation of 3-Pyridinecarbaldehyde 1-Oxide Oxime
Yoshinobu Tagawa, Kazuya Hama, and Yoshinobu Goto*
*Faculty of Pharmaceutical Sciences, Fukuoka University, Nanakuma, Jonan-ku, Fukuoka, 814-01, Japan
Abstract
Treatment of methylpyridines and their 1-oxides with t-butyl nitrite in the presence of potassium t-butoxide in liquid ammonia afforded the corresponding aldoximes in good yields except for the case of 3-methylpyridine. The reaction of 3-methylpyridine with t-butyl nitrite in the presence of lithium 2,2,6,6-tetramethylpiperidide and N,N,N’,N’-tetramethylethylenediamine in tetrahydrofuran at -78 °C led to 3-(3-methyl-4-pyridyl)methylpyridine. Deoxygenation of 3-pyridinecarbaldehyde 1-oxide oxime was effected in 78% yield by the action of t-butyldimethylsilyl chloride-imidzole-sodium iodide-zinc followed by desilylation with tetrabutylammonium fluoride to give 3-pyridinecarbaldehyde oxime.
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■ Dimerization of Indolo[1,2-b][2,7]naphthyridine-5,12-quinone
Deborah A. Davis and Gordon W. Gribble*
*Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, U.S.A.
Abstract
Attempts to isomerize indolo[1,2-b][2,7]naphthyridine-5,12-quinone (5) to ellipticine quinone (7) with various nucleophiles (cyanide, methoxide, halide, thiophenoxide) lead instead to 6,6’-bis(indolo[1,2-b][2,7]naphthyridine-5,12-quinone) (8), the dimer of 5.
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■ Synthesis of 5,8-Quinoxalinediones and 5,8-Quinazolinediones
Yoshiyasu Kitahara, Shinsuke Nakahara, Yoshihiro Tanaka, and Akinori Kubo*
*Meiji College of Pharmacy, 1-35-23 Nozawa, Setagaya-ku, Tokyo 154, Japan
Abstract
5,8-Quinoxalinediones (3a-c, 12, 13), dibenzo[a,c]phenazine-10,13-diones (5a, b), 5,8-quinazolinediones (17, 23), and 4,5,8(3H)-quinazolinetrione (21) were prepared using oxidative demethylation of the corresponding 5,8-dimethoxy compounds with cerium (IV) ammonium nitrate.
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■ The Significance of the Bond Lengths and Bond Orders of Conjugated Unsaturated Organic Molecules. The Role of Hetero-Aromaticity in the Tertiary Structures of DNA
Vernon G. S. Box
*Department of Chemistry, City College of the City, University of New York, Convent Avenue @ 138th Street, New York, NY 10031, U.S.A.
Abstract
New criteria (based on X-ray crystallographic data) for assessing the presence of delocalization in conjugated π systems reveal that delocalization is not a widespread phenomenon in the ground states of many of these π systems. Instead, these molecules prefer to retain highly localized, independent, π systems. Thus, many explanations of the structural features and reactivities of these unsaturated organic molecules, based on their presumed delocalized ground states, must be critically reviewed. This is especially important for understanding the chemistry and properties of hetero-aromatic molecules.