HETEROCYCLES

■ Contents

■ Non-Planar Polycyclic Aromatic Molecules Including Heterole Units

Koki Kise and Takayuki Tanaka*

*Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan

Abstract

Recent developments in non-planar polycyclic aromatic molecules bearing heterole units have been reviewed, including internally and externally heteroatom doped corannulenes, rim and benzylic heteroatom doped sumanenes, hexapyrrolohexaazacoronenes, and hetero[n]circulenes.

■ Microwave-Assisted Approach to Nitroaniline/Aminopyridine and Its Inhibition Activity of Seed Germination

Zhi-you Huang,* Wen-sheng Li, Bo He, Ning Zhang, Zi-Ying Guo, Xiao-Hong Li, and Xian-Jun Yang

*College of Urban and Rural Construction, Shaoyang university, hunan province, China

Abstract

An efficient approach to nitroaniline/aminopyridine was developed under microwave irradiation. The sulphamide and halogenated nitrobenzene/pyridine were used as starting materials. With low consumption, environment friendly, gram-scale synthesis, good substrate scope and excellent product yields, this methodology is superior to the existing approach. Additionally, these compounds 3a-3s could inhibit soybean seed germination at the concentration of 50 µM. Especially, the inhibition rate of compound 3m was higher than 90%.

■ Briarane-Type Diterpenoids from the Cultured Octocoral Briareum stechei (Kükenthal, 1908)

You-Ying Chen, San-Nan Yang, Zhi-Hong Wen, Su-Ying Chien, Jih-Jung Chen, Jui-Hsin Su, Chia-Ching Liaw, Yu-Chi Tsai,* and Ping-Jyun Sung*

*Department of Planning and Research, National Museum of Marine Biology and Aquarium, 2 Houwan Road, Checheng, Pingtung, Taiwan 944, Taiwan

Abstract

A known briarane, excavatolide E (1), along with three previously unreported briaranes, briastecholides D–F (2–4), were purified from an aquacultured form of octocoral Briareum stechei. Spectroscopic approaches were first used to reveal the structures of newly-identified briaranes 2–4; single-crystal X-ray analysis was then performed to identify the absolute configuration of 1. To characterize their biological functions, an anti-inflammatory assay using macrophage cell line RAW264.7 as an in vitro model was employed. The results of the assay showed that briarane 1 prevented the protein production of pro-inflammatory inducible nitric oxide synthase (iNOS) in macrophages caused by lipopolysaccharide stimulation.

■ NH4I-Catalyzed Formal [4+2] Cycloaddition of α,β-Unsaturated O-Acetyl Oxime with Alkyl Pyruvate for Rapid Substituted Pyridine Formation

Dong Cheng, Xiangzhen Meng,* Shuailu Wang, Xuan Zhao, and Jingwen Chen

*School of Chemical Engineering and Life Science, Chaohu College, Chaohu Anhui, Peoples 238000, China

Abstract

A facile synthetic method to substituted pyridines has been developed via the NH4I-catalyzed [4+2] cycloaddition from readily available oxime acetates with alkyl pyruvate. This process involves N-O bond cleavages and C-C bond formations to furnish substituted pyridines under redox-neutral conditions. The reaction features mild conditions and high functional-groups compatibility.

■ Diversity-Oriented Synthesis of 2-Substituted Purine Nucleosides from Available Nucleosides via the Late-Stage Nitration/Derivatization

Ran Xia,* Li-Jie Liu, Chao Xia, Li-Ping Sun, and Lei-Shan Chen*

*Department of Chemistry and Chemical Engineering, Xinxiang University, East of JinSui Road, XinXiang City, Henan Province, 453003, China

Abstract

A practical synthesis of 2-substituted purine nucleosides was developed in good to excellent yields from readily available nucleosides, such as adenosine, vidarabine and 2′-deoxyadenosine, via the late-stage nitration/derivatization. The C(2)-H bonds of purines were nitrated by 2,2,2-trifluoroacetic anhydride/Bu4NNO3, followed by nucleophilic substitution or hydrogenolysis reduction converting C(2)-NO2 to C(2)-Cl, C(2)-F, C(2)-N, C(2)-O and C(2)-S bonds. This system could tolerate arabinofuranosyl, ribosyl, deoxyribosyl, -OH or -NH2 groups. The clinical drugs, Regadenoson, Cladribine and Fludarabine, and the important naturally occurring nucleosides, spongosine and crotonoside, could be obtained successfully even on 20 g scales, which made this route more attractive for industrial applications.

■ Coniferains C and D, New Eunicellin-Based Diterpenoids from Cladiella conifera

Jhao-Syuan Zeng, Tung-Ying Wu, Po-Jen Chen, Wei-Chiung Chi, Nan-Fu Chen, Yang-Chang Wu, Lee-Shing Fang, Shun-Hua Chen,* Liang-Mou Kuo,* and Ping-Jyun Sung*

*Department of Planning and Research, National Museum of Marine Biology and Aquarium, 2 Houwan Road, Checheng, Pingtung, Taiwan 944, Taiwan

Abstract

Chemical examination of Cladiella conifera, collected in the waters of Taiwan, led to the isolation of two new eunicellin-based diterpenoids, coniferains C (1) and D (2). The structures of 1 and 2 were established by spectroscopic methods. Eunicellins 1 and 2 were found to promote cell viability in DLD-1 cells at a concentration of 20 μM.

■ New Bioactive Sesquiterpenoid from Malaysian Soft Coral Genus Lemnalia

Kazuki Tani, Takashi Kamada, Chin-Soon Phan, and Charles S. Vairappan*

*Laboratory of Natural Products Chemistry, Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Malaysia

Abstract

One new sesquiterpenoid, parathyrsoidin K (1) along with seven known related secondary metabolites, parathyrsoidin J (2), lemnal-1(10)-ene-7β,12ζ-diol (3), linardosinene C (4), paralemnolin J (5) and K (6), 1S*,4S*,5S*,10R*-4,10-guaianediol (7), and 4-acetoxy-2,8-neolemnadien-5-one (8), were isolated from the organic extracts of soft coral Lemnalia sp. Their structures were elucidated based on spectroscopic analyses and these compounds were evaluated to anti-inflammatory activity against lipopolysaccharide-stimulated RAW 264.7 macrophages and antifungal activity against seven fungal strains.

■ Chemical Structures and Cell Death Inducing Activities of Constituents Isolated from Hibiscus tiliaceus

Takahiro Kitagawa, Takahiro Matsumoto,* Daisuke Imahori, and Tetsushi Watanabe*

*Public Health, Kyoto Pharmaceutical University, Shichonocho-1, Japan

Abstract

A new coumarin glycoside hibiscuscoumarin (1) was obtained with ten known compounds including seguinoside K (7) from the stems and twigs of Hibiscus tiliaceus. The structure of hibiscuscoumarin (1) was elucidated based on the chemical/physicochemical evidence. The cell death-inducing activities of the isolated compounds with or without Adriamycin (ADR) were observed using time-lapse cell imaging. The isolated compounds did not affect the number of mitotic entry cells and dead cells. Otherwise, the treatment of cells with seguinoside K (7) significantly increased the number of dead cells induced by ADR.

■ Silver-Catalyzed Conversion of CO2 and 2-Ethynylanilines into 4-Hydroxyquinolin-2(1H)-ones in Protic Ionic Liquid at Atmospheric Pressure

Qi Feng,* Keyan Yuan, Miaoqing Zhu, Jingzon You, and Congmin Wang

*Department of Science Education, Zhejiang International Studies University, No. 299, Liuhe Road, Zhejiang International Studies University, Hangzhou, Zhejiang, China

Abstract

4-Hydroxyquinolin-2(1H)-ones are core structural subunits frequently found in many pharmacological compounds and the synthesis of this kind of compounds is highly desirable. An efficient protic ionic liquid and AgNO3 catalytic system was developed for the preparation of various 4-hydroquinolin-2(1H)-ones from CO2 and 2-ethynylanilines in moderate to excellent yields (65-94%). It was found that [HTMG][Im], a simple and easily prepared protic ionic liquid comprising a 1,1,3,3-tetramethylguanidinium cation and a imidazolide anion, could act as both the solvent and reaction promoter, and that the reaction could be efficient carried out with a mount of 2 mol% AgNO3 under atmospheric pressure of CO2 at 60 ℃. This method provides a new approach for the synthesis of 4-hydroxyquinolin-2(1H)-ones.