HETEROCYCLES

■ Contents

■ Phthalocyanines and Related Compounds with Chalcogen Functional Groups

Takeshi Kimura*

*Center for Instrumental Analysis, Iwate University, 4-3-5 Ueda, Morioka, Iwate 020-8551, Japan

Abstract

5,6-Dibromo-4,7-diethylbenzo[1,2,3]trichalcogenoles could be used as starting compounds for phthalocyanines with sulfur or selenium functional groups at β-positions and alkyl groups at α-positions. Phthalocyanines with dithiastannole rings, trithiole rings, and TTF units, phthalocyanines axially linked with 1,2-benzenedithiols, tetraazaporphyrin fused with four thiophene rings, and related derivatives are described in this review.

■ Development of Carbazole Dyes for Efficient Molecular Photovoltaics

Nagatoshi Koumura* and Kohjiro Hara

*Research Center for Photovoltaic Technologies, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, Higashi 1-1-1, Tsukuba, Ibaraki, Japan

Abstract

Dye-Sensitized Solar Cells (DSSCs), which are one of the promising molecular photovoltaics, have been attracting considerable attention because the electrochemical solar cells exhibit high performance and potential for low-cost production. Dyes as photosensitizers are one of the most important components influencing the photovoltaic performances of DSSCs, because a photo-sensitizer determines the photoresponse range of the DSSC and initiates the primary steps of the photon absorption and the subsequent electron transfer process. Generally, Ru-polypyridyl-complex sensitizers, developed by Prof. Grätzel and coworkers, have been employed for efficient DSSCs. In addition to conventional Ru-complex sensitizers, metal-free organic dyes have also been utilized as sensitizers in DSSCs, and the photovoltaic performance of DSSCs based on organic-dye sensitizers has been improved relative to earlier studies of DSSCs with organic dyes. We have designed and synthesized alkyl-functionalized carbazole dyes to improve both solar-cell performance and long-term stability of the solar cells. Here, we report detailed syntheses of several sensitizers based on carbazole and carbazole derivatives donor part, and photovoltaic performances of DSSCs with these dyes.

■ Synthesis of Novel Thiophene-Fused 1,1’-Biazulene Derivative by the Reaction of Azuleno[1,2-b]thiophene with N-Iodosuccinimide

Taku Shoji,* Erika Shimomura, Yuta Inoue, Mitsuhisa Maruyama, Atsuyo Yamamoto, Kunihide Fujimori, Shunji Ito, Masafumi Yasunami, and Noboru Morita

*Department of Chemistry, Faculty of Science, Shinshu University, Asahi, Matsumoto 390-8621, Japan

Abstract

Novel thiophene-fused 1,1’-biazulene derivative was prepared by the reaction of azuleno[1,2-b]thiophene with N-iodosuccinimide. The electronic properties of the new 1,1’-biazulene derivative obtained by the reaction were characterized by CV, DPV, and UV/Vis spectroscopy.

■ Glycosylated Methoxy-Macrolactins from a Marine Sediment Bacterium Bacillus subtilis

Hee Jae Shin,* Fakir Shahidullah Tareq, Ji Hye Kim, Min Ah Lee, Hyi-Seung Lee, Yeon-Ju Lee, and Jong-Seok Lee

*Marine Natural Products Chemistry Laboratory, Korea Institute of Ocean Science & Technology, 787, Haeanro, Ansan 426-744, Korea

Abstract

Fermentation of a bacterium Bacillus subtilis isolated from the marine sediment sample collected at Gageocho, Republic of Korea in sea water based modified Bennett’s medium followed by double ethyl acetate (EA) extraction of the supernatant, sequential fractionations and purifications afforded three new glycosylated methoxy−macrolactins (1−3). The characterization of these compounds was achieved by various spectroscopic techniques including HRESIMS and extensive 1D and 2D NMR data analyses. The stereoconfiguration was assigned based on the chemical derivatization studies and literature data reviews. Methoxy−macrolactins were found to exhibit good antimicrobial properties when tested against bacteria and fungi. But, these compounds did not display any antiplasmodial activity against Plasmodium falciparum (D10).

■ Role of CH/O and CH/π Interactions in Structural Stability. Effect on Endo Selectivity in 1,3-Dipolar Reaction of Electron-Deficient 4-Oxo-4H-pyrazole 1,2-Dioxide with N-Substituted Maleimides

Koki Yamaguchi, Kazunobu Harano, and Masashi Eto*

*Faculty of Pharmaceutical Sciences, Sojo University, 4-22-1, Ikeda, Kumamoto-shi, 860-0082, Japan

Abstract

The molecular structure of the 1:2 cycloadduct derived from 1,3-dipolar reaction of 3,5-bis(methoxycarbonyl)-4-oxo-4H-pyrazole 1,2-dioxide (1a) with N-phenyl maleimide (2a) was established to be an anti-endo-endo form by the single crystal X-ray analysis. The weak attractive CH/O interaction between 1a and 2a is conjectured to play an important role in the preferential formation of the endo transition-state. The formation mechanism of the adduct is discussed on the basis of transition-state structures optimized at the B3LYP/6-31G(d) level of theory.

■ Kinetic Resolution of Secondary Alcohols by Chiral DMAP Derivatives Prepared by the Ugi Multicomponent Reaction

Hiroki Mandai,* Shunsuke Irie, Masaru Akehi, Kazunobu Yuri, Masaaki Yoden, Koichi Mitsudo, and Seiji Suga*

*Division of Chemistry and Biotechnology, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan

Abstract

The kinetic resolution of secondary alcohols was examined by new chiral DMAP derivatives, which can readily be prepared by the Ugi multicomponent reaction in a one-pot operation. The initial screening of DMAP derivatives indicated that the catalyst bearing L-valine with an S configuration at the α-position of amide showed the best stereoselectivity factor. After the reaction conditions were optimized with (S,S)-4a in the kinetic resolution of secondary alcohols, various acyclic and cyclic secondary alcohols could be resolved with an s-factor of up to 12.

■ Synthetic Utility of Ethylidenethiosemicarbazide: Synthesis and Anticancer Activity of 1,3-Thiazines and Thiazoles with Imidazole Moiety

Sobhi M. Gomha, Sayed M. Riyadh,* Ikhlass M. Abbas, and Mohammed A. Bauomi

*Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt

Abstract

Reactions of ethylidenethiosemicarbazide 3 with DMAD 4 or substituted methylenemalononitriles 8 gave thiazolidin-4-one 6 or 1,3-thiazine derivatives (10, 11), respectively. Also, treatment of 3 with hydrazonoyl halides 12a-i, α-haloketones 15a-d, and chloroacetic acid 18 afforded the corresponding arylazothiazoles 14a-i, thiazoles 17a-d, and thiazolin-4-one derivative 20, respectively. The structures of the synthesized products were confirmed by IR, 1H NMR, 13C NMR and mass spectral techniques. The anticancer activity of the selected products against the colon carcinoma cell line (HCT-116) was determined and the results revealed promising activity of compound 6.

■ First Total Syntheses of 1,3-Disubstituted β-Carboline Alkaloids, Dichotomide I and Marinacarbolines A-D

Shinji Tagawa, Tominari Choshi,* Asuka Okamoto, Takashi Nishiyama, Shiroh Watanabe, Noriyuki Hatae, and Satoshi Hibino*

*Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan

Abstract

The first total syntheses of dichotomide I (1), and marinacarbolines A-D (3-6) were achieved in four steps from methyl 1-chloro-β-carboline-3-carboxlyate (9), which was previously used as a synthetic intermediate of dichotomine C. The required compound 9 was prepared in a six-step sequence including a microwave-assisted thermal electrocyclic reaction of a 1-azahexatriene system.

■ Synthesis of Some Novel Binuclear Heterocyclic Compounds from 6-Ethyl-3-nitropyrano[3,2-c]quinoline-4,5(6H)-dione

Hany M. Hassanin* and Dalia Abdel-Kader

*Department of Chemistry, Faculty of Education, Ain Shams University, Roxy, Cairo 11711, Egypt

Abstract

6-Ethyl-3-nitropyrano[3,2-c]quinoline-4,5(6H)-dione (4) was synthesized and its reactivity towards some 1,2-, 1,3-, and 1,4-binucleophiles was investigated. Ring transformation via opening of the γ-pyrone ring and heterocyclizations through out these reactions led to certain interesting five, six, and seven-membered heterocyclic substituents, viz. pyrazolyl, pyridyl, pyrimidyl, diazepinyl, and thiazepinyl at position-3 of quinolin-2-one moiety.

■ A Unique and Simple Preparative Method for α-Arylpipecolinic Acid Esters via Base-Induced Sommelet–Hauser Rearrangement

Eiji Tayama,* Ryota Sato, Motoshi Ito, Hajime Iwamoto, and Eietsu Hasegawa

*Department of Chemistry, Faculty of Sciences, Niigata University, Ikarasi 2-8050, Niigata 950-2181, Japan

Abstract

A unique and simple preparative method for N-cyano-α-arylpipecolinic acid esters via base-induced Sommelet–Hauser rearrangement, the von Braun reaction, and intramolecular α-alkylation is reported. The removal of the N-cyano substituent was achieved by hydrogenation and hydride reduction.

■ Synthesis of 3,4-Dihydroisoquinolines by Cyclization of 1-Bromo-2-(2-isocyanoalkyl)benzenes with Butyllithium

Kazuhiro Kobayashi,* Naoki Matsumoto, and Kota Matsumoto

*Division of Applied Chemistry, Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan

Abstract

A new and convenient method for the preparation of 3,3-disubstituted 3,4-dihydroisoquinolines has been developed. Thus, the reaction of 1-bromo-2-(bromomethyl)benzenes with (1-isocyano-1-lithioalkyl)benzenes, generated by the treatment of (1-isocyanoalkyl)benzenes with butyllithium, in THF at –78 ˚C gave the corresponding 1-(2-aryl-2-isocyanoalkyl)-2-bromobenzenes, which in turn were transformed into the desired products on treatment with butyllithium in THF at –78 ˚C.

■ Zirconium Catalyzed Chemoselective Synthesis of New Amido-Substituted Benzo[b]furans via a One-Pot Reaction

Bahador Karami,* Saeed Khodabakhshi, and Hamid Reza Vahabinia

*Department of Chemistry, Yasouj University, P.O.Box 353, Yasouj 75918-74831, Iran

Abstract

A one-pot, three-component reaction of arylglyoxals, benzamide and phenols using catalytic amounts of zirconium oxychloride octahydrate under solvent-free conditions produce new amido-substituted benzo[b]furans. The reactions showed chemoselectivity towards benzofuran instead of oxazols which this claim has been confirmed by nuclear magnetic resonance (NMR) and infrared spectroscopy (IR).

■ Microwave-Assisted Synthesis and Crystal Structure of Novel 2-Dichloromethyl-1,3-dioxolanes

Fei Ye, Ying Li, Ying Fu,* Shuang Gao, and Li-Xia Zhao

*Department of Applied Chemistry, College of Sciences, Northwest Agricultural University, Harbin 150030, Heilongjiang, China

Abstract

An efficient synthesis of 2-dichloromethyl-1,3-dioxolane derivatives with microwave-assisted addition reaction was developed. The intermediate 1,3-dioxolanes 2 were obtained by exposing to microwave radiation with glycol at the present of anhydrous CuSO4. A series of novel 2-dichloromethyl-1,3-dioxolane derivatives 3 were synthesized by carbenes insertion of dioxolanes 2 and chloroform with TEBA used as phase transfer catalyst. The structures of the compounds were characterized by IR, 1H-NMR, 13C-NMR spectroscopy, and elemental analysis. The configuration of 3f was determined by X-ray crystallography.

■ Melanogenesis-Modulating Diketopiperazine Derivatives from Hypocrea spp.

Tetsuro Kawabata,* Chiaki Uchida, Hikaru Kato, Tomoyuki Tsubata, Fumihide Takano, and Tomihisa Ohta

*School of Pharmacy and Pharmaceutical Sciences, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan

Abstract

A new dioxopiperazine derivative, hypocreasin (1), and five known (2–6) compounds were isolated from the fungus Hypocrea spp. The structure of 1 was determined by 1D/2D NMR and MS spectroscopic analyses. Compound 2 increased melanogenesis but 3 inhibited it in cultured murine melanoma B16F1 cells.

■ A Practical Synthesis of a Hydroxylated Sesquiterpene Coumarin 10’R-Acetoxy-11’-hydroxyumbelliprenin by Regioselective Dihydroxylation

Yasunao Hattori, Genki Kinami, Kenta Teruya, Kazuto Nosaka, Kazuya Kobayashi, and Kenichi Akaji*

*Department of Medicinal Chemistry, Pharmacetuical Chemistry, Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8412, Japan

Abstract

A practical synthesis of 10’R-acetoxy-11’-hydroxyumbelliprenin was achieved using regioselective Sharpless asymmetric dihydroxylation as a key reaction, in which the regioselectivity was achieved by using (DHQD)2AQN as a ligand instead of the conventional (DHQD)2PHAL. 10’R-Acetoxy-11’-hydroxyumbelliprenin was synthesized by the coupling of a coumarin unit (umbelliferone) and sesquiterpene unit in 11% overall yield through 5 steps.