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. 6, 1990
Published online:
■ Enzymatic Cyclization Involving Intramolecular Michael Addition by Catalase: Formation of 2-Methylbenzimidazoles
Ahmed Kamal* and Riaz Hashim
*Organic Chemistry Division III, Indian Institute of Chemical Technology, Hyderabad 500 007, India
Abstract
Catalase-mediated intramolecular cyclization of ethyl β-2-aminoanilinocrotonates gives 2-methylbenzimidazoles in good yields
Published online:
■ The Birch Reduction/Alkylation of Phthalides. The Synthesis of Some Substituted Bicyclo[3.2.1]octanes
Vernon G. S. Box* and George P. Yiannikouros
*Department of Chemistry, The City College of the City University of New York, Convent Avenue @ 138th Street, New York, NY 10031, U.S.A.
Abstract
The first successful reductions of the aromatic rings of phthalides, with the preservation of the lactone rings, are reported. The reduction/alkylation of some substituted 4-methoxyphthalides gave lactonic enol ethers, which were converted into conjugated homocyclic dienes and further into cyclohexenones. These enones were easily converted into bicyclo[3.2.1]octanes by the Bu3SnH/AIBN free radical cyclization reaction.
Published online:
■ A Novel 1,6 Cyclization of Imidazolium N-Allylides (1) : Formation of Mesomeric Betaines, 8-Oxoimidazo[1,2-a]pyridiniumides
Yoshiro Matsuda,* Hiromi Gotou, Keisuke Katou, Hiroshi Matsumoto, Makoto Yamashita, Kimitoshi Takahashi, and Shizuki Ide
*School of Pharmaceutical Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan
Abstract
Treatment of imidazolium N-allylides (3a,b) in refluxing xylene resulted in 1,5-dipolar cyclization to give pyrroloimidazoles (4a,b), whereas heating of N-allylides (3c,d,e) in refluxing xylene gave the mesomeric betaines, 8-oxoimidazo[1,2-a]pyridiniumides (5a,b,c), with 1,6 cyclization. Furthermore, treatment of the N-aminoimidazolium salt (9) and ketene dithioacetal (2c) with potassium carbonate in dimethyl sulfoxide (DMSO) directly afforded the mesomeric betaine, imidazo[1,2-b]pyridaziniumide (11). The benzimidazolium salt (12) and directly ethoxymethylenemalonate (2d) were treated with potassium carbonate in CHCl3 to also produce the mesomeric betaine, 4-oxobenz[b]imidazo[1,2-a]pyridiniumide (14).
Published online:
■ A New Synthesis of 2,12-Dithia[3.3](1,4)cycl[3.2.2]azinophanes
Yoshiro Matsuda,* Hiromi Gotou, Keisuke Katou, Hiroshi Matsumoto, Makoto Yamashita, Kimitoshi Takahashi, and Shizuki Ide
*School of Pharmaceutical Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan
Abstract
2,12-dithia[3.3](1,4)cycl[3.2.2]azinophanes (11, 12) which were the key intermediates for the synthesis of [2.2](1,4)cycl[3.2.2]azinophanes (1, 2) were synthesized by the reaction of bis(mercaptomethyl)cyclazine (10) and dihalogenated compounds (2,6-lutidine dibromide, 8c) with Cs2CO3 in N,N-dimethylformamide (DMF).
Published online:
■ Novel Bromolactonization Using a Dimethyl Sulfoxide-Trimethylsilyl Bromide-Amine System; Unusual cis-Addition of trans-6-Substituted 3-Cyclohexene-1-carboxylic Acids
Chuzo Iwata,* Akira Tanaka, Hiroaki Minuzo, and Kazuyki Miyashita
*Faculty of Pharmaceutical Sciences, Osaka University, Yamada-oka 1-6, Suita, Osaka 565, Japan
Abstract
A novel method for bromolactonization using a dimethyl sulfoxide-trimethylsilyl bromide-amine system and first example for halolactonization in the mode of cis-addition are described.
Published online:
■ Intramolecular Diels-Alder Reactions of 2-Vinylindoles: A New Approach to Functionalized Carbazoles
John E. Macor*
*Department of Medical Chemistry, Central Research Division, Pfizer Inc., Groton, Connecticut 06355, U.S.A.
Abstract
Intramolecular Diels-Alder reactions of 2-vinylindoles are discussed. When the dienophile is appended to C2 of the 2-vinylindole, these reactions represent a novel approach to carbazole derivatives.
Published online:
■ Synthetic Studies on Manzamine A I: Diels-Alder Reaction of 5,6-Dihydro-2-pyridinone
Masako Nakagawa,* Ziping Lai, Yasuhiro Torisawa, and Tohru Hino*
*Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
Abstract
Various hydroisoquinolines have been synthesized via the Diels-Alder reactions of 5,6-dihydro-2-pyridinones with Danishefsky diene.
Published online:
■ Furannulation Strategy. An Efficient Synthesis of Fused 3-Methylfurans
Mariko Aso, Mizue Sakamoto, Narumi Urakawa, and Ken Kanematsu*
*Institute of Synthetic Organic Chemistry, Faculty of Pharmaceutical Sciences, Kyushu University 62, Maidashi, Higashi-ku, Fukuoka 812, Japan
Abstract
A two-step synthesis of fused 3-methylfurans (furannulation) by the addition of enolate anion of cyclic 1,3-dicarbonyl compounds to allenic sulfonium salt is described.
Published online:
■ Synthesis of Isoquinoine Precursors by Photoamination of Stilbenes with Bifunctional Alkylamines
Masahide Yasuda,* Jun-ichi Kubo, and Kensuke Shima
*Department of Industrial Chemistry, Faculty of Engineering, Miyazaki University, Gakuen-Kibanadai, Miyazaki 889-21, Japan
Abstract
Irradiation of stilbenes (1) with amino alcohols or amino acetaldehyde diethyl acetal in the presence of p-dicyanobenzene gave the corresponding N-substituted 1,2-diarylethylamines (2) in good yields. The resulting benzylamino alcohols and benzylamino acetals were treated with CF3SO3H and gaseous BF3, respectively, to give isoquinolines (4, 5 and 6).
Published online:
■ Acid Degradation Products of Qinghaosu and Their Structure-Activity Relationships
Yasuhiro Imakura,* Katsutoshi Hachiya, Tomomi Ikemoto, Shinsuke Yamashita, Masaru Kihara, Shigeru Kobayashi, Tetsuro Shingu, Wilbur K. Milhous, and Kuo-Hsiung Lee
*Faculty of Sciences, Naruto University of Education, Takashima, Naruto-shi, Tokushima 772- , Japan
Abstract
Treatment of qinghaosu (1) with acid yielded 1’,2’,4’-trioxanes (5 and 8), endoperoxides (6 and 9), and diketones (7 and 10). Structures of 5, 6, 7, 8, 9, and 10 were assigned based on their physical and spectral data. Structure-activity correlation among these compounds indicated the steric requirement of the 1’,2’,4’-trioxane ring system as found in 1 for potent antimalarial activity.
Published online:
■ An Asymmetric Synthesis of a Quaternary Chiral Building Block from Ethylmalonic Acid: A Preparation of Key Synthetic Intermediates of Hunteria- and Aspidosperma-type Indole Alkaloids
Masataka Ihara, Ken Yasui, Nobuaki Takayanagi, and Keiichiro Fukumoto*
*Faculty of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba-ku, sendai 980-8578, Japan
Abstract
The major product, obtainted by allylation of the (-)-phenylmethyl half ester (4) of ethylmalonic acid, was converted into two lactones (11) and (16), the key intermediates for indole alkaloids of Hunteria- and Aspidosperma-type.
Published online:
■ Mass Spectral Fragmentation Patterns of 3,6-Dihydro-1,2-oxazines
Kenryk Labaziewicz,* Robert E. Kohrman, and Bob A. Howell
*Department of Chemistry, Central Michigan University, Mt. Pleaasant, MI 48859, U.S.A.
Abstract
Electron impact induced fragmentation of twenty-nine, 3,6-dihydro-1,2-oxazines occurs via two competitive pathways. The first is the formation of a pyrrole system by loss of water from the molecular ion. The second pathway involves a retro Diels-Alder reaction to generate the butadienyl system as the most stable fargmentation product. The spectra contain low intensity peaks corresponding to the nitroso component of the retro cycloaddition process.
Published online:
■ An Improved Synthesis of 6-Hydroxy-4-[2-(di-n-propyramino)ethyl]indole
John P. Mayer, John M. Cassady, and David E. Nichols*
*Department of Medicinal Chemistry and Molecular Pharmacognosy, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette IN 47907, U.S.A.
Abstract
An efficient synthesis is reported for the putative 6-hydroxy metabolite of 4-[2-(di-n-propylamino)ethyl]indole (DPAI), a potent dopaminergic agent.
Published online:
■ A Convenient Synthesis of 3,5’-Bipyrazolyl Derivatives via Hydrazonyl Halides
Hamdi M. Hassaneen,* Ahmad S. Shawali, and Nehal M. Elwan
*Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt
Abstract
Cycloaddition of N-phenyl-C-cinnamonitrilimine 3 with enolates of various active methylene compounds afforded the 3-styrylpyrazole derivatives 6-10 in high yields. 3-Styrylpyrazoles 6-13 reacted with diphenylnitrilimine 20 to give the correspondign 3,5’-bipyrazolyl derivatives 21-28, respectively.
Published online:
■ The Reaction of β-Aminoenones with α-Amino Derivatives. Synthesis of 2-Functionalized Pyrroles
Angel Alberola,* José M. Andrés, Alfonso González, Rafael Pedrosa, and Martina Vicente
*Deparamento de Química Orgánica, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid, Spain
Abstract
β-Aminoenones react with ethyl glycinate, α-aminoacetonitrile and α-aminoacetamide hydrochlorides leading to 2-functionalized pyrroles. Although the transamination is a high-yield process, the transformation of the intermediate, in both basic or thermally induced conditions, affords the corresponding pyrroles in poor to moderate yields.
Published online:
■ Nucleophilic Aromatic Substitution of a Methoxy Group by an Alkylthio Group in the Case of 10-Substituted 2-Methoxy-9-thioacridinones
Djeridi Dhif, Jean-Pierre Galy,* Jacques Barbe, and José Elguero
*Laboratoire de Chimie Organique, Faculté de Pharmacie, Université de la Méditerranée, 27, Boulevard Jean Moulin, 13385 Marseille Cedex 05, France
Abstract
The synthesis and nmr study (1H and 13C) of eleven acridine derivatives are reported. 13C chemical shifts are very sensitive to the oxygen or sulfur nature of the substituents at positions 2 (alkoxy vs thioalkoxy) and 9 (acridinones vs thioacridinones). The rather unusual replacement of an alkoxy group by a thioalkoxy group in thioacridinones, when treated by alkyl mercaptans in the presence of aluminium chloride, is described.
Published online:
■ Regioselective Cleavage Reaction of the Methylenedioxy Ring in Aromatic Compounds Containing Electron-withdrawing Groups with Sodium Alkoxides-Alcohols in Dimethyl Sulfoxide
Yasuhiro Imakura,* Kazuto Okimoto, Chizuru Gorohata, Shigeru Kobayashi, Masaru Kihara, and Shinsuke Yamashita
*Faculty of Sciences, Naruto University of Education, Takashima, Naruto-shi, Tokushima 772- , Japan
Abstract
The reaction of 6-bromopiperonal (1) with sodium alkoxides (MeONa or PhCH2ONa)-alcohols (MeOH or PhCH2OH), and sodium alkoxides (MeONa, PhCH2Na or PhONa)-phenol (PhOH) in dimethyl sulfoxide gave 3-hydroxybenzene derivatives (3, 5 and 6) and 4-hydroxybenzene derivative (4), respectively. The reactivity and formational mechanism of various nucleophilic reagents (alkoxide anions) formed from the alcohols and phenol by sodium alkoxides in the regioselective cleavage reactions are discussed.
Published online:
■ N-Methylsecoglaucine, a New Phenanthrene Alkaloid from Fumariaceae
Olga Blanco, Luis Castedo,* Magdalena Cid, Julio A. Seijas, and Carmen Villaverde
*Departamento de Química Orgánica, Facultad de Farmacia, Universidad de Santiago de Compostela, E-15706, Santiago de Compostela, Spain
Abstract
The isolation and its total synthesis of the new phenanthrene alkaloid N-methylsecoglaucine (1) from Platycapnos spicata are reported.
Published online:
■ Studies on Aconitum Species. XIII. Two New Diterpenoid Alkaloids from Aconitum yesonese var. Macroyesoense (Nakai) Tamura. VI.
Koji Wada, Hideo Bando, and Norio Kawahara*
*Hokkaido Institute of Pharmaceutical Sciences, 7-1 Katsuraoka-cho, Otaru 047-02, Japan
Abstract
A new C20-diterpenoid alkaloid, yesodine (1), a new C19-diterpenoid alkaloid, yesodine (2), and two known alkaloids, macrocentridine (3) and subcusine (4), were isolated from aconitum yesoense var. macroyesoense (Nakai) Tamura. Structures of those new alkaloids were determined on the basis of their spectra and chemical correlation with known alkaloids.
Published online:
■ Synthesis of N,N’-[Bis(adenosin-8-yl)]diaminoalkanes and -piperazine
Yuris A. Maurinsh, Keiko Sujino, Hideo Togo, and Masataka Yokoyama*
*Department of Chemistry, Faculty of Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
Abstract
Several N,N’-[bis(adenosin-8-yl)]diaminoalkanes and -piperazine were prepared by the following procedure; 8-bromoadenosine reacted with diamines to give the corresponding N-(adenosin-8-yl)diaminoalkanes and -piperazine, which were then converted into the title compounds by treatment with another 8-bromoadenosine.
Published online:
■ Selectivity of Nucleophilic Substitution on 3-Substituted 2,6-Dichloropyridines with Alkoxide. Pyridinophane Preparation
Toshio Kawato* and George R. Newkome
*Laboratory of Chemistry, College of General Education, Kyushu University, Ropponmatsu, Chuo-ku, Fukuoka 812-8582, Japan
Abstract
Electron withdrawing groups at the 3-position of 2,6-dichloropyridines were found to assist nucleophilic displacement of the 2-chloro group with alkoxide. Pyridinophanes were prepared via stepwise substitution.
Published online:
■ Direct Synthesis of 2-Substituted 5-Formylpyrimidines and Ring Transformation of Their Phenylhydrazones into 4-Formyl-1-phenylpyrazole
Kaname Takagi, Abdelilah Bajnati, and Michel Hubert-Habart*
*Section de Physique et Chimie, Institut Curie, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France
Abstract
Triformylmethane (1) reacted with benzamidine, guanidine and 5-methylisothiourea to give 2-substituted 5-formylpyrimidines (2a-c), whose phenylhydrazones (3a-c) readily underwent ring transformation into 4-formyl-1-phenylpyrazole (4) on heating in acidic methanol.
Published online:
■ Ratibinolide, a New Sesquiterpene Lactone from Ratibida latipalearis
Rachel Mata,* Alejandra Rojas, Manuel Soriano, Rene Villena, Robert Bye, and Edelmira Linares
*Instituto de Química, Universidad Nacional Autónama de México, Circuito Exterior, Ciudad Universitaria, Coyoacán 04510, Mexico
Abstract
Ratibinolide 1, a new sesquiterpene lactone has been isolated, using brine shrimp lethality for activity guided fractionation from Ratibida latipalearis. Its structure was established through spectral and X-ray crystallographic analyses.
Published online:
■ On the Reactivity of Halo-1,3-azoles and Related Compounds toward Aromatic SN2 Substitution
Hiroshi Yamanaka,* Setsuya Ohba, and Takao Sakamoto
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
Nucleophilic addition-elimination reactions of 2-methylsulfonyl-1,3-azoles with active methylene compounds were investigated in order to compare the reactivity of substrates. The order of oxazole > thiazole >> N-methylimidazole in the reactivity was exhibited clearly. Furthermore, in oxazole and thiazole series, the predominant reactivity of the 2-position over the 4- and 5-positions was indicated on the reaction with the carbanions generated from active methylene compounds.
Published online:
■ Synthesis of Novel 1,3-Thiazolidines and 1,3,4-Thiadiazolines from Thiocarbohydrazines
Shigeru Kabashima, Tadashi Okawara, Tetsuo Yamasaki, and Mitsuru Furukawa*
*Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-hon-machi, Kumamoto 862-0973, Japan
Abstract
The reaction of thiocarbohydrazide (1) with α-bromo-γ-butyrolactone (2) provided the novel 1,3-thiazolidine (3). Alkylidenethiocarbohydrazides (8 and 13) were allowed to react with cyanogen bromide and acetyl chloride to give 4,5-dihydro-1,3,4-thiadiazoles (9 and 14).
Published online:
■ A New Entry to Pyrazolo[1,5-a]pyrido[3,4-e]pyrimidine Derivatives
Fabrizio Bruni,* Stefano Chimichi,* Barbara Cosimelli, Annarella Costanzo, Gabriella Guerrini, and Silvia Selleri
*Dipartimento di Scienze Farmaceutiche, Via Gino Capponi 9, 50121 Firenze, Italy
Abstract
Treatment of 3-aminopyrazoles (1a-e) with 3-ehoxymethylenpentane-2,4-dione afforded in the new pyrazolo[1,5-a]pyrimidines (2a-e) which were then converted into the enamines (3a-e) by reaction with dimethylformamide dimethyl acetal; ring closure of these latter compounds led to pyraozolo[1,5-a]pyrido[3,4-e]pyrimidines (5a-e).
Published online:
■ A Radical Approach to Bharatamine, a Unique Protoberberine Alkaloid from Alangium lamarckii
Seiichi Takano,* Mahito Suzuki, and Kunio Ogasawara
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
Bharatamine, a unique racemic protoberberine alkaloid from Alangium lamarckii, has been synthesized via aryl radical-inithiated 1,6-cyclization as the key step.
Published online:
■ The Role of Lone Pair Interactions in the Chemistry of the Monosaccharides. The Anomeric Effects
Vernon G. S. Box
*Department of Chemistry, The City College of the City University of New York, Convent Avenue @ 138th Street, New York, NY 10031, U.S.A.
Abstract
The electronic factors which contribute to the anomeric effects have been attributed to the destabilizing n-n (lone pair - lone pair), or/and the stabilizing n-σ*, interactions of the non-bonded electron pairs of geminal heteroatoms. Predictions of the chemistry of the simple monosaccharide acetals, based on a n-σ* hypothesis, are not consistent with the experimentally observed chemistry. Thus, the n-σ* hypothesis is not a useful model for rationalizing the chemical reactivity of acetals, or the closely related anomeric effects. A study of the X-ray crystallographic data of some monosaccharides also casts considerable doubt on the validity of the bond length and bond angle criteria that have beenused to assert the importance of the n-σ* hypothesis. A hypothesis based on dominant n-n interactions, with a minor contribution from the n-σ* interactions, is a better model for rationalizing the chemistry of the simple acetals. This combination of electronic factors illuminates both the anomeric effects and the chemistry of the acetals.