HETEROCYCLES

■ Contents

■ Air-Stable and High-Mobility Organic Semiconductors Based on Heteroarenes for Field-Effect Transistors

Shoji Shinamura, Itaru Osaka, Eigo Miyazaki, and Kazuo Takimiya*

*Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan

Abstract

Recent developments on heteroarene-based organic semiconductors applicable to high-performance, air-stable thin-film p-channel transistors are described. For the development of these new materials, including benzo[1,2-b:4,5-b']dichalcogenophenes (BDXs), [1]benzochalcogenopheno[3,2-b][1]benzochalcogenophenes (BXBXs), and dinaphtho[2,3-b:2',3'-f]chalcogenopheno[3,2-b]chalcogenophenes (DNXXs), new efficient synthetic methods are established. These materials are then evaluated as active layers in organic field-effect transistors (OFETs) fabricated by vacuum or solution processes. In the present work, molecular factors (molecular structures, energy levels and shapes of highest occupied molecular orbitals, molecular arrangements in the thin film) and the device performances are correlated and discussed to understand a structure-properties relationship. As a consequence of this approach, several air-stable and high-performance semiconductors for the OTFTs are successfully developed. For example, vapor-processable DNTT and solution-processable alkylated-BTBTs showing field-effect mobility as high as 3.0 cm2 V–1 s–1 and with 2.8 cm2 V–1 s–1, respectively, are among the best for recently developed new materials.

■ Synthetic Studies on Nitrogen-Containing Fused-Heterocyclic Compounds Based on Thermal Electrocyclic Reactions of 6π-Electron and Aza 6π-Electron Systems

Tominari Choshi and Satoshi Hibino*

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

Abstract

Syntheses of carbazole alkaloids and indoles by an allene-mediated electrocyclic reaction of a 6π-electron system (II) through a tautomeric process, and syntheses of several fused pyridine ring systems including alkaloids by a thermal electrocyclic reaction of an aza 6π-electron system having an oxime or isocyanate (III) through either the elimination of a small molecule or a tautomeric process are described.

■ Survey of Briarane-Type Diterpenoids – Part IV

Ping-Jyun Sung,* Jui-Hsin Su, Wei-Hsien Wang, Jyh-Horng Sheu, Lee-Shing Fang, Yang-Chang Wu, Yung-Husan Chen, Hsu-Ming Chung, Yin-Di Su, and Yu-Chia Chang

* , National Museum of Marine Biology and Aquarium, 2 Houwan Road, Checheng, Pingtung, Taiwan 944, Taiwan, R.O.C.

Abstract

The structures, names, bioactivities, and references of 90 briarane-type diterpenoids, including 59 new compounds, are described in this review. All the briarane-type compounds mentioned in this review article were obtained from various octocorals including Briareum, Dichotella, Ellisella, Junceella, Menella, Verrucella, and Ptilosarcus. Some of these compounds showed potential bioactivities.

■ Steric Effect on the Formation of 3H-Azepine Derivatives from o-Alkylphenylnitrene and Alcohol as a Nucleophilic Media

Siti Mariyah Ulfa, Hideki Okamoto, and Kyosuke Satake*

*Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan

Abstract

The cause of regioselectivity for the formation of 3-alkyl- and/or 7-alkyl-3H-azepine derivatives via the intramolecular insertion reaction of o-alkylphenylnitrene, which is generated by an action of Bu3P on o-alkylnitrobenzene, in the presence of alcohol found to be elucidated by the steric effects of an alcohol adduct on the dehydroazepine intermediate. Observed selectivity is confirmed both by changing the bulkiness of the o-alkyl group of phenylnitrene and that of alcohol as a nucleophile.

■ Regioselective One-Pot Synthesis of 2-Aryl-6-bromobenzothiazole from Arylaldehyde and 2-Aminothiophenol with Phenyltrimethylammonium Tribromide in the Presence of a Catalytic Amount of Antimony(III) Bromide

Shinsei Sayama*

*Department of Chemistry, Fukushima Medical University, Hikarigaoka, Fukushima, 960-1295, Japan

Abstract

Various 2-aryl-6-bromo-1,3-benzothiazoles were regioselectively afforded in good yields by the reaction of arylaldehydes and 2-aminothiophenol with phenyltrimethylammonium tribromide in the presence of a catalytic amount of SbBr3 in CH2Cl2 at room temperature.

■ Synthesis, Structure, and Theoretical Calculations of 1H-3,7-Difurylcyclopenta[3,4-d]pyridazine

Chad A. Snyder,* Nathan C. Tice, Jeremy B. Maddox, Sean Parkin, Aaron W. Daniel, and Jaron M. Thomas

*Department of Chemistry, Western Kentucky University , Bowling Green, Kentucky 42101-1079, U.S.A.

Abstract

Treating [M{η5-1,2-C5H3(COC4H3O)2}(CO)3] (3) (M = Mn, 3A, M = Re, 3B) with excess hydrazine hydrate in methanol afforded the desired 5,6-fused ring pyridazine complexes, [M(CO)3{η5-1,2-C5H3(CC4H3ON)(CC4H3ON)}] (4) (M = Mn, 4A, M = Re, 4B), in high yield (76%). However, when X-ray crystallographic analysis of the pyridazyl complexes 4A and 4B was attempted, all recrystallization trials led to ligand loss to the 1,2-difurylpyridazine, 1,2-C5H3(CC4H3ONH)(CC4H3ON) (5). Compound 5 was observed to have a coplanar stacking arrangement in the solid state along the crystallographic b axis. Theoretical calculations performed on compound 5 indicate a high degree of intramolecular electronic delocalization as well intermolecular orbital interaction.

■ Xanthones in Heterocyclic Synthesis. An Efficient and General Route for the Synthesis of Regioselectively Substituted Phthalazines

Yiannis Gardikis, Petros G. Tsoungas,* Constantinos Potamitis, George Pairas, Maria Zervou, and Paul Cordopatis*

*Research & Technology, Ministry of Education, 14-18 Messogeion Ave., Athens, GR-115 10, Greece

Abstract

Xanthone undergoes regioselective substitution and nucleophically - triggered ring opening to the corresponding ketone. Hydrazone of the latter oxidatively rearranges to ortho-diacylarenes, which, then, with hydrazine gives regioselectively substituted phthalazines. Molecular modeling analysis and 1H NMR spectra indicate and intramolecular H-bonding engaging phenol OH and phthalazine N-3 atom.

■ Synthesis of 3,1-Benzothiazines from 2-Alkenyl- and 2-Alkynylanilides and Lawesson Reagent

Kentaro Okuma,* Saori Ozaki, Noriyoshi Nagahora, and Kosei Shioji

*Department of Chemistry, Faculty of Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan

Abstract

Reaction of 2-vinylacetanilide with P4S10 gave 2-vinylthioacetanilide, whereas reaction of 2-vinylacetanilide with Lawesson reagent (LR) afforded 2,4-dimethyl-4H-3,1-benzothiazine in 62% yield. Reaction of 2-alkynylanilides with LR gave 4-exomethylene-4H-3,1-benzothiazines in good yields.

■ Polycyclic N-Heterocyclic Compounds. Part 70: Synthesis of 5-Amino-1,2-dihydrofuro[2,3-b]pyrido[3’,2’:4,5]thieno[3,2-d]pyridines and Related Compounds. Evaluation of Effects on Lipoprotein Lipase mRNA Expression

Kensuke Okuda,* Hideyasu Takechi, Takashi Hirota, and Kenji Sasaki

*Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan

Abstract

Reaction of 3-(3-cyanopropoxy)thieno[2,3-b]pyridine-2-carbonitriles with potassium tert-butoxide gave 5-amino-1,2-dihydrofuro[2,3-b]pyrido[3’,2’:4,5]thieno[3,2-d]pyridines via a Truce-Smiles rearrangement. The 5-amino group was transformed to the chloro derivatives which were allowed to react with various nucleophiles. Effects of the newly synthesized compounds on lipoprotein lipase mRNA expression were also evaluated. The previously unreported parent compound, furo[2,3-b]pyrido[3’,2’:4,5]thieno[3,2-d]pyridine, was also synthesized.

■ Asymmetric Cyclization Reactions of N-Benzoyl-α-dehydroarylalanine Alkyl Esters via Photoinduced Electron Transfer from Achiral and Chiral Amines

Yuji Sasaki, Haruo Watanabe, Tetsutaro Igarashi, and Tadamitsu Sakurai*

*Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan

Abstract

Irradiation of the title compounds [(Z)-1] having (S)-(+)-sec-butyl, (–)-menthyl, and related chiral auxiliaries in methanol and 1,2-dichloroethane containing 2-(diethylamino)ethanol afforded chiral auxiliary-substituted (4S,5S)-, (4R,5R)-, (4R,5S)-, and (4S,5R)-4,5-dihydrooxazole derivatives (2) along with (E)-1. It was found that the photoinduced electron transfer-initiated cyclization of (Z)-1 gives either of the two diastereomers for cis-2 and trans-2 in diastereomeric excess whose value varies from 8 to 81% depending on the property of solvent as well as on the steric bulkiness of chiral auxiliary. On the other hand, the asymmetric photocyclization of chiral auxiliary-unsubstituted (Z)-1 in 1,2-dichloroethane proceeded cleanly in the presence of the chiral amine, (S)-(–)-1-methylpyrrolidine-2-methanol, to give (4R,5R)-2 and (4R,5S)-2 in enantiomeric excess of 17–38% and 20–33%, respectively, depending on the steric bulkiness of the aryl substituent. A mechanistic consideration of these diastereoselective and enantioselective photocyclization reactions enabled us to propose major factors controlling the extent of asymmetric photoinduction.

■ Convenient One-Pot Synthesis of 3-Aryl-2H-chromene-4-carbonitriles via a Tandem O-Alkylation-Knoevenagel Condensatioin

Yanhong Chen, Haoyue Xiang, Yuyuan Xie, and Chunhao Yang*

*State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, SIBS, Chinese Academy of Science, 555 Zu Chong Zhi Road, Shanghai 201203, China

Abstract

3-Aryl-2H-chromene-4-carbonitriles were synthesized through one-pot tandem reaction of easily available 2-(2-hydroxyphenyl)acetonitrile (1) and 2-bromo-1-arylethanones (2) under the condition of K2CO3/dioxane. These functionalized chromenes could be useful building-blocks for estrogen receptor ligands and other related heterocycles.

■ Reactions of 3,6-Bis(3,5-dimethyl-4-R-pyrazol-1-yl)-1,2,4,5-tetrazines with Indole and 1,3,3-Trimethyl-2-methyleneindoline

Rashida I. Ishmetova, Nina K. Ignatenko, Ilya N. Ganebnykh, Svetlana G. Tolshchina, Pavel A. Slepukhin, and Gennady L. Rusinov*

*I. Ya. Postovsky Institute of Organic Synthesis of RAS, 620990, S. Kovalevskoy st, 22, Yekaterinburg, Russia

Abstract

It has been found that 3,6-bis(3,5-dimethyl-4-R-pyrazol-1-yl)-1,2,4,5-tetrazines react with indole and 1,3,3-trimethyl-2-methyleneindoline to give pyridazines as [4+2]cycloaddition products. 1,3,3-Trimethyl-2-methyleneindoline has been shown to act as C-nucleophile in the substitution of pyrazolyl group as well as in the reactions of tetrazine ring expansion in [1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine derivatives.

■ An Efficient Arylation of Benzoazoles with Aryl Bromides by a Practical Palladium-Copper Cocatalytic System

Xue-Ming Yan, Xue-Rong Mao, and Zhi-Zhen Huang*

*School of Chemistry and Chemical Engineering , Nanjing University, Nanjing 210093, China

Abstract

A practical, efficient Pd(OAc)2/Cu(II)/PPh3 cocatalytic system has been developed. With only 1 mol% Pd(OAc)2, 20 mol% copper(II) salt, and 0.5 equiv of inexpensive PPh3 as ligand, the direct arylation of benzoazoles with aryl bromides could be performed smoothly in mild condition, affording the desired arylated benzoazoles in good yields (75-93%).

■ New Red Pigments from Lichen Lethariella sinensis

Ayako Tanaka, Kaoru Kinoshita, Koji Ichinose, Tadayasu Togawa, Kiyotaka Koyama, Takao Narui, Li-song Wang, and Kunio Takahashi*

*Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan

Abstract

New red pigments were isolated from a lichen thallus, Lethariella sinensis by Wei & Jiang. The structures of the red pigments, rubrosinensiquinones A (1), B (2), and C (3), were determined by spectroscopic analyses.

■ Synthesis of 1-Deoxyeldecalcitol, a Biologically Interesting Analog of 1α,25-Dihydroxy-2β-(3-hydroxypropoxy)vitamin D3 (Eldecalcitol)

Hirotaka Sasaki, Kohei Eto, Keisuke Takahashi, Jun Ishihara, Susumi Hatakeyama, and Noboru Kubodera*

*Chugai Pharmaceutical Company, Ltd., 2-1-1, Nihonbashi-Muromachi, Chuo-ku, Tokyo 103-8324, Japan

Abstract

A synthesis of biologically interesting 1-deoxyeldecalcitol, a dehydroxylated analog at the 1α-position of 1α,25-dihydroxy-2β-(3-hydroxy- propoxy)vitamin D3 (eldecalcitol), using Trost’s coupling methodology is described.

■ Formation of the 1H-Pyrrolo[3,4-c]pyridin-1-one Skeleton via Intramolecular Diels-Alder Reaction of Oxazoles

Masashi Ohba,* Kei Fukuyama, Yuko Izumi, and Masaki Inaki

*Yokohama College of Pharmacy, 601, Matano-cho, Totsuka-ku, Yokohama 245-0066, Japan

Abstract

The 1H-pyrrolo[3,4-c]pyridin-1-one derivatives (4a–c) were prepared through a route employing the intramolecular Diels–Alder reaction of the oxazole–olefins (3a–c). Conversion of the crotonamide (3a) into 4a was effectively promoted by the addition of Cu(OTf)2 as a catalyst.

■ Purinium Derivatives with Antitumor Activities from Heterostemma alatum Wight

Wen-Wei Fu, Chang-Heng Tan,* Peng-Yu Zhuang, Shu-Min Yang, Hong-Feng Luo, Jun-Jie Tan, Ping Liu, and Da-Yuan Zhu

*Department of Natural Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China

Abstract

Heteromine I (1), a new purinium derivative, together with six known compounds, were isolated from the aerial parts of Heterostemma alatum Wight. The structure of 1 has been established as 2-methylamino-6-methoxy-7,9-dimethyl-8-purinone by means of spectroscopic analysis. Two puriniums, heteromines J (2) and K (3) were isolated as natural products for the first time. Heteromine D (4) showed strong cytotoxicity against HL-60 cell line with IC50 of 4.04 nmol/mL.

■ Synthesis of 12,12a-Dihydro-7,12a-diazacyclohepta[cd]benz[g]azulen-12-one (Cyclohepta[mn]pyrrolo[1,2-c][1,4]benzodiazepin-12-one) and Evaluation of Cytotoxic Activity against HeLa S3 Cells

Eiko Yoshioka, Hiroyuki Fujii, Toshihiro Murafuji, Reiko Ikeda, Takeo Konakahara, Takahiro Gunji, and Noritaka Abe*

*Department of Industrial Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan

Abstract

12,12a-dihydro-7,12a-diazacyclohepta[cd]benz[g]azulen-12-one (cyclohepta[mn]pyrrolo[2,1-c][1,4]benzodiazepin-12-one) derivative (7) was synthesized by the intramolecular cyclization of methyl 2-(3-phenyl-1-azaazulen-8-yl)aminobenzoate. Compound (7) showed extremely strong cytotoxic activity against HeLa S3 cells (IC50=0.543±0.063 μM).