HETEROCYCLES

■ Contents

■ Synthetic Methods of 1,3,2-Diazaphosphinine Systems

Tarik E. Ali,* Mohammed A. Assiri, Ahmed M. Fouda, Mohamed M. Hassan, and Noha M. Hassanin

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

Abstract

The present review considers all the literature data on methods developed for the synthesis of 1,3,2-diazaphosphinine systems starting from their appearance up to end 2018. The described main methods depended on the cyclization of 1,3-diamines, 1,2-aminoamide (β-aminoamide) and 1,2-aminonitrile (β-aminonitrile) compounds with phosphorus halides and sulfides.

■ Total Synthesis of Thermoactinoamide A and Its Analogue

Yueguang Sun, Hang-bin Li, Rong Zhou, Hailin Wang, Pengju Feng,* and Shihai Xu*

*Department of Chemistry, Jinan University, Guangzhou City, 510632, China

Abstract

Thermoactinoamide A, showing remarkable antibacterial properties, is a novel cyclic hexapeptide which was originally isolated from thermophilic bacterium. We disclosed here the first total synthesis of thermoactinoamide A and its analogue, anti-thermoactinoamide A, by the Fmoc solid-phase peptide synthesis and subsequent efficient macrolactamization. Thermoactinoamide A and its analogue can be obtained in 74% and 46% overall yield respectively without any isomerization under the developed methodology.

■ Total Synthesis of Proposed Structure of Azepinobisindole Alkaloid Rhodozepinone

Tomoki Itoh and Takumi Abe*

*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan

Abstract

Total synthesis of the proposed structure of azepinobisindole alkaloid rhodozepinone has been accomplished from simple starting materials in 4 steps for the first time.

■ Uncariagambiriines B and C, Alkaloid-Catechin Hybrids from Uncaria gambir Leaves

Mutsumi Oshima, Hiroe Aoyama, Yuuki Shimozu, Shoko Taniguchi, Takanori Miura, and Tsutomu Hatano*

*Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan

Abstract

Gambiers, aqueous extracts from the leaves and twigs of Uncaria gambir, are used medicinally in Asian countries. Previously, we reported the isolation of uncariagambiriine (1) from U. gambir leaves, and its unique structure regarded as a catechin-alkaloid hybrid. Our continuing studies led to the isolation of two previously undescribed compounds named uncariagambiriines B (2) and C (3), in addition to the flavonoid glycosides, hyperoside and isoquercitrin. The structures of 2 and 3, isomeric to 1, were elucidated based on their spectral data.

■ Synthesis and Optical Properties of Polyarylimidazole Derivatives Containing Naphthyl Groups In the 4,5-Positions for Coated and Non-Doped OLED Materials

Keiji Mizuki,* Daiki Sakai, Yuri Hatashima, and Taizo Hatta

*Department of Nanoscience, Faculty of Engineering, Sojo University, 4-22-1, Ikeda, Kumamoto-shi, 860-0082, Japan

Abstract

In this study, we describe the development of an imidazole emitting material, characterized by low concentration quenching via a bulky substituent group, for coated and non-doped OLEDs. Specifically, we synthesized novel 1,2,4,5-tetraarylimidazoles that have naphthyl groups replacing the bulky aryl groups at the 4,5-positions and investigated their optical, concentration quenching, thermal, and coating properties. We observe that the emitting materials had low concentration quenching properties and fluorescence occurred even in the film coating state.

■ Synthesis of Steroidal [1,2,4]Triazolo[1,5-a]pyrimidines and Their Antiproliferative Activities

Ning-Juan Fan, Jiang-Jiang Tang, Yuan-Feng Li, Yu-Bin Bai, and Xiao-Min Zhao*

*College of Veterinary Medicine, Northwest A＆F University, Yangling, Shaanxi 712100, China

Abstract

A facile strategy for the synthesis of steroidal [1,2,4]triazolo[1,5-a]pyrimidines 5a-g and 6a-g has been accomplished via a one-pot reaction of steroidal ketones, aromatic aldehydes and 3-amino-1,2,4-triazole in the presence of potassium tert-butoxide in refluxing tert-butanol. All the synthesized heterosteroids were evaluated for in vitro antiproliferative activity against human cancer cells by sulforhodamine B (SRB) assays. The preliminary results showed that compounds 6a and 6e possessed potent antiproliferative activities.

■ Thymidine, 2-Thiothymidine, and 2-Selenothymidine: Comparison of Mismatch Discriminations

Takaki Habuchi, Takao Yamaguchi, and Satoshi Obika*

*Pharmaceutical Science, Osaka University, 1-6 Yamadaoka, Suita, Osaka 560-0871, Japan

Abstract

Oligonucleotides modified using 2-thiothymidine (S2T) or 2-selenothymidine (Se2T), which are thymidine analogs bearing either sulfur or selenium atoms, respectively, have been independently shown to suppress the formation of mismatched wobble base pairs with guanine when forming a duplex with single stranded DNA. However, limited data comparing the base discriminations of S2T- and Se2T-modified oligonucleotides, especially toward single stranded RNA, are available. Here, we report a comprehensive data set of the base discriminations of S2T- and Se2T-modified oligonucleotides toward both single stranded DNA and RNA. Our results demonstrate that S2T- and Se2T-modified oligonucleotides have similar base discrimination abilities. An important feature observed in both the S2T- and Se2T-modified oligonucleotides is their extremely high base discrimination toward single stranded RNA. Thus, S2T and Se2T modifications may be useful for therapeutic oligonucleotides targeting single stranded RNAs.

■ A Mild and Efficient Ga(OTf)3-Catalysed Friedländer Reaction for the Synthesis of Quinolines

Hani Mutlak A. Hassan* and Iuliana Denetiu

*King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589 80216, Saudi Arabia

Abstract

The application of gallium triflate [Ga(OTf)3] for the synthesis of quinolines via the Friedländer reaction is described. This mild and straightforward method employed only 1 mol% of Ga(OTf)3 to deliver the quinoline products in excellent yields, demonstrating the high catalytic activity of this rare earth metal triflate.

■ An Efficient Three-Component Synthesis of Novel Spiro[pyrazole-4,2’-quinazoline] Derivatives

Hayate Nagabuchi, Eiichi Masumoto, Fumi Okabe-Nakahara, and Hiroshi Maruoka*

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

Abstract

A simple, efficient, and three-component procedure has been developed for the synthesis of a series of spiropyrazol-3-one derivatives containing dihydroquinazoline moiety by the reaction of 1H-pyrazole-4,5-diones, 2-aminobenzophenones, and ammonium acetate in moderate to good yields. This method provides several advantages such as operational simplicity, shorter reaction time, and higher yields. All the synthesized compounds were characterized by spectroscopic analysis.