HETEROCYCLES

■ Contents

■ Synthesis of Functionalized Cyclic Molecules by Palladium-Catalyzed Cyclization of Propargylic Esters with Bis-nucleophiles

Masahiro Yoshida*

*Graduate School of Pharmaceutical Sciences, The University of Tokushima, Sho-machi, Tokushima 770-8505, Japan

Abstract

It is known that propargylic esters react with palladium complex leading to π-propargylpalladium complexes, which further cause various transformations in the presence of soft nucleophiles to produce the corresponding products. Among them, palladium-catalyzed cyclization of propargylic esters with bis-nucleophiles is one of the useful methodologies for the construction of functionalized cyclic molecules in one step. Since the pioneering work reported by Tsuji in 1985, a considerable number of reactions have been reported by the use of various bis-nucleophiles. In this review, a comprehensive overview of the studies on palladium-catalyzed reactions of propargylic esters with bis-nucleophiles is described, in which various functionalized cyclic molecules can be synthesized in a regio- and stereoselective manner.

■ NOVEL NITENPYRAM ANALOGUES WITH TETRAHYDROPYRIDONE-FIXED CIS-CONFIGURATION: SYNTHESIS, INSECTICIDAL ACTIVITIES, AND MOLECULAR DOCKING STUDIES

Chuan-Wen Sun,* Jing Wang, Ying Wu, Shi-Bin Nan, and Wang-Geng Zhang

*College of Life and Environmental Science, Shanghai Normal University , No. 100 Guilin road, Shanghai 200234, China

Abstract

To make further researches on the diversity of nitenpyram analogues with a cis-nitromethylene configuration, a series of cis-nitenpyram analogues (3a-q) with tetrahydropyridone fixed cis-configuration were designed and synthesized. Preliminary bioassays showed that most of the designed nitenpyram analogues exhibited good insecticidal activity at 100 mg/L against Nilaparvata lugens and Myzus persicae, while analogues 3n afforded the best in vitro activity. Modeling the ligand-receptor complexes by molecular docking study revealed the analogues 3 with various substituents on phenyl show their different binding affinities to the insect nAChR, which also explained the structure-activity relationships observed in vitro.

■ A CONVENIENT SYNTHESIS OF 2-MERCAPTO-OXAZOLES VIA β-KETOAZIDE AND ITS APPLICATION TO A KEY INTERMEDIATE OF PI3Kγ INHIBITORS

Yusuke Oka,* Tetsuya Yabuuchi, and Yoshinori Sekiguchi

*Medicinal Chemistry Laboratories, Taisho Pharmaceutical Co., Ltd., 1-403 Yoshino-Cho, Kita-ku, Saitama-city, Saitama 331-9530, Japan

Abstract

A convenient synthesis of 2-mercapto-oxazoles via the reaction of β-ketoazide with triphenylphosphine (TPP) and carbon disulfide and its application to the synthesis of a key intermediate of phosphoinositide 3-kinase γ (PI3Kγ) inhibitors are described.

■ A Metal-Free Oxidation of Benzo[c]chromen to Benzo[c]chromen-6-ones by t-Butyl Hydroperoxide in the Presence of Potassium Iodide

Jing Zhou, Pan Han, Ying-Meng Xu, Tao Zhang, and Zhen-Ting Du*

*College of Science, Northwest A＆F University, Yangling 712100, Shaanxi Province, China

Abstract

An effective and eco-friendly oxidation method for the synthesis of benzo[c]chromen-6-ones is described. The condition constitutes 6 molar ratio TBHP, catalytic KI and pyridine in acetonitrile as the solvent. Altogether, 16 structurally diverse substituted benzo[c]chromen-6-ones were prepared through this protocol from corresponding benzo[c]chromenes in excellent yields.

■ NAPHTHOQUINONES AND PHENALENONE DERIVATIVES FROM THE CULTURED LICHEN MYCOBIONTS OF TRYPETHELIUM SP.

Yukiko Takenaka, Yuki Naito, Duy Hoang Le, Nobuo Hamada, and Takao Tanahashi*

*Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada-ku, Kobe 658-8558, Japan

Abstract

Abstract – Spore-derived mycobionts of the crustose lichen Trypethelium sp. collected in Vietnam were cultivated on a malt-yeast extract medium supplemented with 10% sucrose. The investigation of their metabolites resulted in isolation of a new naphthoquinone and a new phenalenone derivative, together with (+)-trypethelone methyl ether and (+)-sclerodin. Their structures were determined by spectroscopic methods.

■ Bifunctionalized Allenes. Part X. An Electrophilic Cyclization Protocol for Convenient Highly Regioselective Synthesis of 3-Sulfonylfuran-2(5H)-ones from 2-Sulfonylallenoates

Valerij Ch. Christov,* Ivaylo K. Ivanov, and Ismail E. Ismailov

*Department of Organic Chemistry & Technology, Konstantin Preslavsky University of Shumen, 115, Universitetska str. BG-9712 Shumen, Bulgaria

Abstract

A simple and convenient protocol for the highly regioselective synthesis of 3-sulfonylfuran-2(5H)-ones by electrophilic cyclization reaction of 2-sulfonylallenecarboxylates with neighbouring ester group participation is described. However, the reaction of 2-sulfonylalka-2,3-dien-1-ones with electrophilic reagents proceeded with formation of 2-sulfonylalka-2,4-dien-1-ones by addition-elimination reaction. A possible mechanism involving the cyclization and addition-elimination reaction of 2-sulfonyl-substituted allenic esters and ketones was proposed.

■ ONE-POT SYNTHESIS OF 11,23-BIS(IMIDAZOL-1-YL)CALIX[4]ARENE DERIVATIVES BASED ON THE UPPER RIM OF BIS-AMINOCALIX[4]ARENE

Bing Zhao, Yao-Yu Ruan, Ming-jie Ma, Qi-Gang Deng,* Li-Yan Wang, Ya-Qing Feng, and Yan Gao*

*College of Chemistry and Chemical Engineering, Qiqihar University, 42 Wenhuadajie, Qiqihar, Heilongjian Shang, 161006, China

Abstract

A simple one-pot synthesis for a new 11,23-bis(imidazol-1-yl)calix[4]arene derivatives in their cone conformation was reported by the four component condensation reaction of 11,23-bis-aminocalix[4]arene, aldehyde, benzil and ammonium acetate. This work provides a simple, efficient method for the construction of 11,23-bis(imidazol-1-yl)calix[4]arene derivatives on which the substituted imidazole rings are directly linked to their upper rim.

■ Convenient Synthesis of 6-Amino-3,4-dihydro-2H-pyrimido[2,1-a]isoquinoline-7-carbonitriles and 5-Amino-2,3-dihydroimidazo[2,1-a]isoquinoline-6-carbonitriles

Kazuhiro Kobayashi,* Kosuke Ezaki, and Toshihide Komatsu

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

Abstract

An efficient method for the preparation of 6-amino-3,4-dihydro-2H-pyrimido[2,1-a]isoquinoline-7-carbonitriles and 5- amino-2,3-dihydroimidazo[2,1-a]isoquinoline-6-carbonitriles by the copper(I) iodide catalyzed reaction of 2-(2-bromophenyl)-1,4,5,6-tetrahydropyrimidines and 2-(2-bromophenyl)-4,5-dihydro-3H-imidazoles, respectively, with 1,3-propanedinitrile (malononitrile) in DMSO in the presence of excess potassium carbonate has been developed.