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. 75, No. 12, 2008
Published online: 24th July, 2008
■ Reaction of Hydrazines and Hydroxylamine with Trifluoromethyl-β-diketones: Synthesis of Trifluoromethylpyrazole and Isoxazole Derivatives
Vinod Kumar, Ranjana Aggarwal, and Shiv P. Singh*
*Department of Chemistry, Kurukshetra University, Kurukshetra -136 119, India
Abstract
The reaction of trifluoromethyl-β-diketones with hydrazines and hydroxylamine finds interesting application in the synthesis of trifluoromethylpyrazole and isoxazole derivatives. The review covers the literature of the reactions mentioned up to 2007. Mechanistic aspects leading to the formation of these heterocycles and their NMR spectral characteristics are also described.
Published online: 11th August, 2008
■ Rhodium-catalyzed Arylation of 2-Azabicyclo[2.2.1]hept- 5-en-3-one with Arylboronic Acids under Microwave Irradiation
Takumi Abe, Hiroyuki Takeda, Yumi Takahashi, Yoshihisa Miwa, Koji Yamada, and Minoru Ishikura*
*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan
Abstract
Rhodium-catalyzed arylation of 2-azabicyclo[2.2.1]hept-5-en-3-one was successfully performed by applying microwave irradiation.
Published online: 10th July, 2008
■ Synthesis and Antimicrobial Evaluation of Some Bis(thioxopyridine), Bis(pyrazolo[3,4-b]pyridine), Bis(thieno[2,3-b]pyridine), Bis(1,3,4-Thiadiazole) and Bisthiophene Derivatives
Nabila A. Kheder, Yahia N. Mabkhot, and Ahmad M. Farag*
*Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt
Abstract
Condensation of the N,N’-(ethane-1,2-diyl)bis(cyanoacetamide) (1) with aromatic aldehydes gave the corresponding N,N’-ethane-1,2-diyl)- bis(2-cyano- 3-phenylacrylamide) derivatives 2a-c. The latter products react with 2-cyanothioacetamide to afford 1,2-bis(4-aryl-3,5-dicyano-6-mercapto-2-oxo-1,2- dihydropyridin-1-yl)ethane derivatives 5a-c. Treatment of 1,2-bis(3,5-dicyano- 6-mercapto-2-oxo-4-phenyl-1,2-dihydropyridin-1-yl)ethane (5a) or its S-methyl derivative 6 with hydrazine hydrate afforded 1,2-bis(3-amino-5-cyano-6,7- dihydro-7-methyl-6-oxo-4-phenyl-1H-pyrazolo[3,4-b]pyridin-1-yl)ethane (7). Reaction of bis(6-mercaptopyridine) 5b with chloroacetone gave the 1,2- bis[2-acetyl-3-amino-6,7-dihydro-5-cyano-4-(4-methoxyphenyl)-6-oxothieno[2,3-b]pyridine-7-yl]ethane (9). Treatment of the bis(cyanoacetamide) 1 with phenyl isothiocyanate afforded N,N’-(ethane-1,2-diyl)bis[2-cyano-3-mercapto-3-(phenyl amino)acrylamide] (11) which reacts with hydrazonoyl halides 12a,b or haloketones 15a-c to give the corresponding N,N’-(ethane-1,2-diyl)bis[2-cyano- 2-(3,5-disubstituted-2(3H)-1,3,4-thiadiazolylidene)acetamides] 14a,b or N,N’-(ethane-1,2-diyl)bis[4-amino-5-substituted-2-(phenylamino)thiophene-3-carboxamide] 16a-c derivatives, respectively. Antimicrobial evaluation of selected example of the newly synthesized compounds was carried out.
Published online: 10th July, 2008
■ A New Approach to the Benzopyridoxepine Core by Metal Mediated Intramolecular Biaryl Ether Formation
Georgeta Serban,* Hitoshi Abe, Yasuo Takeuchi, and Takashi Harayama*
*Faculty of Medicine and Pharmacy, Oradea University, Oradea 410028, Romania
Abstract
This paper presents a concise synthesis of the novel [1,3]dioxo[d]benzoxepino[2,3-c]-6-bromopyridine 1. The benzopyridoxepine core has been obtained by intramolecular coupling of a benzopyridylethene that is in turn obtained from the Wittig reaction. Thus, the synthesis was accomplished in a very good yield by implementation of an intramolecular palladium-catalyzed biaryl ether formation (Buchwald-Hartwig type reaction). An alternative approach based on the copper-mediated C-O bond formation (intramolecular Ullmann reaction) was not successful.
Published online: 17th July, 2008
■ Efficient Formation of a Triazole Ring via Novel Ring-opening Reaction of (Z)-2-Methyl-4-arylmethylene-5(4H)-oxazolones with Hydrazides
Kei Maekawa, Atsushi Tomoda, Tetsutaro Igarashi, and Tadamitsu Sakurai*
*Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, Kanagawa-ku, Yokohama 221-8686, Japan
Abstract
The ring-opening mode of the title oxazolones with hydrazide nucleophiles was investigated from both synthetic and mechanistic points of view. It was found that the novel ring-opening reaction proceeded to give (Z)-2-(3-methyl-5-substituted 1,2,4-triazol-4-yl)-3-aryl-2-propenoic acids [1,2,4-triazole-substituted (Z)-α-dehydroarylalanines] as major products, along with minor or negligible amounts of their isomers. Substituent and solvent effects on the relative composition of these two isomers confirmed that this composition was dependent on steric and electronic factors of the aryl (in the oxazolones) and acyl (in the hydrazide nucleophiles) substituents as well as on solvent polarity. MM2 and PM5 calculations provided a strong piece of evidence in support of the mechanism in which the triazole ring is constructed via the preferential nucleophilic addition of the hydrazino nitrogen to the C=N double bond in the oxazolone ring.
Published online: 17th July, 2008
■ A Simple and Practical Synthesis of Methyl Benzo[b]furan-3-carboxylates
Ferdinand S. Melkonyan, Nikita E. Golantsov, and Alexander V. Karchava*
*Department of Chemistry, M. V. Lomonosov Moscow State University, Moscow 119992, Russia
Abstract
A simple and practical two-step procedure for the preparation of 2-unsubstituted 1-benzo[b]furan-3-carboxylic acid methyl esters is described. The procedure uses the copper-catalyzed intramolecular C-O bond formation and provides an efficient route to the title compounds in good to excellent yields.
Published online: 17th July, 2008
■ Rearrangement of Dialkyl-2-(azetidin-3-yl)propane-1,3-dioates - A Structural Revision
Mark R. Faust, Cornelia E. Hoesl, and Klaus T. Wanner*
*Department of Pharmacy - Center for Drug Research, LMU Munich, Butenandtstr. 5-13, D-81377 Munich, Germany
Abstract
The rearrangement reaction of dialkyl 2-[1-diphenylmethyl)azetidin-3-yl]propane-1,3-dioates during saponification was studied. Contrary to a previous report postulating the formation of a 4-(hydroxy-methyl)-2-oxo-pyrrolidine-3-carboxylic acid derivative, our analytical data showed that the rearrangement reaction led to a lactone ring. This structural revision is based on elemental analysis, IR and two-dimensional NMR studies.
Published online: 10th July, 2008
■ Facile Synthesis of Model Indazolo[2,1-c][1,3,4]benzotriazepin-5,13-diones
Jalal A. Zahra, Mustafa M. El-Abadelah,* Bassam A. Abu Thaher, Stefan Laufer, and Roland Boes
*Chemistry Department, Faculty of Science, University of Jordan, Amman, Jordan
Abstract
In basic media, 2-aminobenzoic acids (5) react with 2-[N-(1-carboxyphenyl)]hydrazonoyl chlorides (6, 7) (precursors of the reactive nitrile imine 1,3-dipolar species) to afford good yields of the corresponding 2-[N’-(1-carboxyphenyl-2-amino)hydrazino]benzoic acids (8a-d, 9a). The latter acyclic adducts, in the presence of 1,1‘-carbonyldiimidazole (CDI), undergo two consecutive lactamizations involving both activated carboxyl groups and the suitably located hydrazino-NH partners, to deliver the respective indazolo[2,1-c]- [1,3,4]benzotriazepin- 5,13-diones (10a-d, 11a). Structural assignments for these novel tetracyclic products are based on analytical and spectral (IR, MS, NMR) data, and confirmed by single crystal X-ray structure determination for 10a.
Published online: 4th August, 2008
■ Synthesis and Antimicrobial Evaluation of Novel Pyrazolo[1,5-a]pyrimidine, Pyrimido[1,2-a]benzimidazole, Triazolo[4,3-a]pyrimidine and Pyrido[1,2-a]benzimidazole Derivatives Incorporated Phenylsulfonyl Moiety
Mohamed R. Shaaban*
*Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt
Abstract
Phenylsulfonylacetonitrile (1) reacts with dimethylformamide dimethyl acetal (DMF-DMA) to afford 3-(dimethylamino)-2-(phenylsulfonyl)acrylonitrile (2). Enaminonitrile 2 reacts with 5-aminopyrazole derivatives 3a-e, 2-amino-1,2,4-triazole (7) and 2-aminobenzimidazole (11) to afford new pyrazolo[1,5-a]pyrimidine, triazolo[4,3-a]pyrimidine and pyrimido[1,2-a]benzimidazole derivatives 4a-e, 9 and 12, respectively. Also, 3-(dimethylamino)-2-(phenylsulfonyl)acrylonitrile (2) reacts with 2-(1H-benzimidazol-2-yl)acetonitrile (13) to give the corresponding pyrido[1,2-a]benzimidazole derivative 15. Some of the newly synthesized compounds were tested in vitro for their antibacterial and antifungal activities, and showed promising results.
Published online: 28th July, 2008
■ Novel and Efficient Access to Thieno[3,4-c]cinnolines
Karine Gehanne, Jean-Charles Lancelot, Stéphane Lemaître, Hussein El-Kashef, and Sylvain Rault*
*Centre d’Etudes et de Recherche sur le Médicament de Normandie UPRES EA 4258 PR CNRS INC3M - Université de Caen Basse-Normandie, U.F.R. des Sciences Pharmaceutiques, 5, rue Vaubénard - 14032 Caen, France
Abstract
New substituted methyl thieno[3,4-c]cinnoline-3-carboxylate compounds were synthesized from the corresponding methyl 3-aminothiophene-2-carboxylate precursors by a new route using a modified Sandmeyer reaction. Under proper conditions, Sandmeyer reaction led to the formation of thieno[3,4-c] cinnoline compounds by a regioselective intramolecular cyclization, instead of the expected substitution of the amino group by a bromine atom.
Published online: 31st July, 2008
■ Synthesis of 1-Iminoisothiochroman Derivatives Based on Reactions of 2-Lithio-β-methoxystyrene Derivatives with Isothiocyanates Followed by Acid-mediated Cyclization
Kazuhiro Kobayashi,* Daisuke Nakai, Kazutaka Hayashi, and Hisatoshi Konishi
*Division of Applied Chemistry, Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan
Abstract
The reaction of 2-lithio-β-methoxystyrene derivatives with isothiocyanates yields the corresponding 2-(2-methoxyvinyl)thiobenzamide derivatives. Treatment of these thiobenzamides with concentrated hydriodic acid affords 1-imino-3-methoxyisothiochroman (1-imino-3-methoxy-3,4-dihydro-1H- 2-benzothiopyran) derivatives.
Published online: 18th August, 2008
■ Furanoeremophilanes and Other Constituents of Pittocaulon bombycophole
Jhon Ironzi Maldonado R., Amira Arciniegas, Ana-L. Pérez Castorena, José Luis Villaseñor, and Alfonso Romo de Vivar*
*Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, CoyoacÁn 04510, D.F. México
Abstract
Three new eremophilanes (1-3) and a new oplopane (4) were isolated from Pittocaulon bombycophole. Additionally, three known sesquiterpenes (5-7) and the alkaloid 7-angeloylplatynecine (8) were isolated. The structures of the new compounds were elucidated by spectroscopic methods.
Published online: 22nd July, 2008
■ Grayanane Diterpenoids from the Barks of Craibiodendron henryi
Xiang-zhong Huang,* Rong Huang, Gang Du, Yan Yin, Yun Dai, and Ming-qian Yu
*School of Chemistry and Biotechnology, Yunnan Nationalities University, Kunming 650031, People’s Republic of China
Abstract
Three new grayanane diterpenoids, 14β-O-(2S,3R-nilyl)rhodomollein XVIII (1), 14β-O-(2S,3R-nilyl)rhodomollein I (2) and 14β-O-(2S,3R-nilyl) rhodojaponin III (3) have been isolated from the barks of Craibiodendron henryi. Their structures were determined on the basis of chemical and spectral methods. Vasodilator effects of these compounds were assessed.
Published online: 10th July, 2008
■ Singaporentine A: A New Indole Alkaloid from Kopsia singapurensis Ridl.
Khalijah Awang,* Kartini Ahmad, Noel F. Thomas, Yusuke Hirasawa, Koichi Takeya, Mat Ropi Mukhtar, Khalit Mohamad, and Hiroshi Morita
*Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
Abstract
Study on chemical constituents from the leaves of Kopsia singapurensis (Apocynaceae) yielded a new indole alkaloid, singaporentine A (1) together with two known alkaloids, kopsifoline A (2) and kopsininic acid (3). The structure of 1 was elucidated by combination of various spectroscopic methods such as MS, UV, IR, 1D and 2D NMR. Singaporentine A exhibited cytotoxic activity against P388 murine leukemia cells.
Published online: 4th August, 2008
■ Coumarins and Flavones from Casimiroa pringlei
Emma Maldonado, Imelda Márquez, Fernando Chiang, and Alfredo Ortega*
*Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Coyoacán, 04510, D. F., México
Abstract
A chemical study of the leaves of Casimiroa pringlei led to the isolation of six coumarins, six flavones and the sesquiterpene, cryptomeridiol. Four of these compounds are new natural products which, on the basis of spectroscopic analyses, were characterized as (Z)-trichoclin acetate, 5,3’,5’-trimethoxyflavone, 5,2’,3’,4’-tetramethoxyflavone, and 5,2’,3’,4’,5’,6’-hexamethoxyflavone. Although 5,2’,3’,4’-tetramethoxyflavone has been obtained by synthesis, this is the first report of its isolation from a natural source.
Published online: 10th July, 2008
■ An Alternative Preparation of Pyrazolo-pyridine Derivatives in Ionic Liquid and Comparison Study on the Reactivity of Thioamide and Amide Group
Xin-Ying Zhang, Xiao-Yan Li, Xue-Sen Fan,* Xia Wang, Gui-Rong Qu,* and Jian-Ji Wang
*School of Chemical and Environmental Sciences, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, Henan 453007, P. R. China
Abstract
A novel and efficient preparation of pyrazolo[3,4-b]pyridine (5) and pyrazolo[3,4-b]pyridin-6-one (8) derivatives from the condensation of arylidenecyanothioacetamide (1) or arylidenecyanoacetamide (7) with 5-amino- 3-methyl-1-phenylpyrazole (4) in [bmim]BF4 is reported for the first time. The mechanism for the formation of 5 from 1 and 4, or 8 from 7 and 4, and the comparison between the reactivity of thioamide group versus amide group are briefly discussed.
Published online: 18th August, 2008
■ Efficient Synthesis of 1,8-Dioxo-octahydroxanthenes Using HClO4/SiO2 as Catalyst
Gholam Hossein Mahdavinia, Mohammad A. Bigdeli,* Yaser Saeidi Hayeniaz, and Firouzeh Nemati
*Faculty of Chemistry, Tarbiat Moalem University, 49 Mofateh St., Tehran, Iran
Abstract
Silica supported perchloric acid (HClO4/SiO2) is found to be a heterogeneous recyclable catalyst for rapid and efficient synthesis of 1,8-dioxo-octahydroxanthenes with good to excellent yields in solvent free conditions. The catalyst is easily prepared, stable, reusable and efficiently used under reaction condition.
Published online: 17th July, 2008
■ Studies of the Egyptian Traditional Folk Medicines. IV. New Isoflavonoid Isolated from Egyptian Licorice
Masaki Baba,* Sakiko Sumi, Noriaki Iwasaki, Hisahiro Kai, Masami Sakano (nee Komiya), Yoshihito Okada, and Toru Okuyama
*Natural Medicine and Phytochemistry, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588 Japan
Abstract
A new isoflavonoid, 2′,4′-dihydroxy[6″,6″-dimethylpyrano (2″,3″:7,8)]isoflavone, named isoglabrone, was isolated from the ethyl acetate extract of Egyptian licorice, Glycyrrhiza glabra, together with 10 known phenolic compounds. The structure was elucidated on the basis of spectrometric evidence.
Published online: 17th July, 2008
■ A Mild and Efficient Synthesis of New 3-Phenylthienotriazolopyrimidine Derivatives Using Iodobenzene Diacetate
Byeoung Sun Joe, Hoon Young Son, and Yang-Heon Song*
*Department of Chemistry, Mokwon University, Daejeon 302-729, Republic of Korea
Abstract
New 3-phenylthieno[3,2-e][1,2,4]triazolo[4,3-c]pyrimidine 9a-i and 3-phenylthieno[2,3-e][1,2,4]triazolo[4,3-c]pyrimidine 10a-i derivatives were easily synthesized at rt in high yield by the oxidative cyclization of thienopyrimidinyl hydrazones using iodobenzene diacetate.