Study on One-pot Preparation of Pyrazoles, Thiazoles, and Tetrazoles from Arenes

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05118
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 33020:Synthetic organic chemistry-related
• Research Institution: Chiba University
• Principal Investigator: Togo Hideo 千葉大学, 大学院理学研究院, 教授 (60217461)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: ピラゾール / イソキサゾール / チアゾール / イミダゾール / キノリン / テトラゾール / フェナンスリジン / ワンポット合成

Outline of Final Research Achievements

Treatment of arenes with α-bromoacetyl chloride and AlCl3, followed by the reaction with thioamides and amidines gave the corresponding 4-arylthiazoles and 4-arylimidazoles in good yields, treatment of alkylarenes with NBS, followed by the reaction with thioureas provided the corresponding 2-amino-4-arylthiazoles in good to moderate yields, and successive treatment of arenes with β-bromopropionyl chloride and AlCl3, followed by the reactions with hydrazines and Na2CO3 gave the corresponding 3-arylpyrazoles in good to moderate yields. Moreover, successive treatment of arenes with acyl chlorides and AlCl3, the addition of water and removal of solvent, the reaction with NH2OH-HCl and K2CO3, and the reaction with DPPA and DBU under warming conditions gave the corresponding 5-alkyl-1-aryltetrazoles in good to moderate yields. All those reactions for the preparation of nitrogen-containing heteroaromatics were carried out in one pot under transition-metal-free conditions.

Free Research Field

有機化学

Academic Significance and Societal Importance of the Research Achievements

千葉県が世界的なヨウ素生産拠点であること、及びヨウ素が環境負荷の少ない元素であることから、ヨウ素及び関連ヨウ素試剤を用いた含窒素芳香族複素環の新規ワンポット合成反応開発、及びそれらの手法を用いた含窒素芳香族複素環骨格を有する生物活性・薬理活性化合物合成への応用を展開することにより、ヨウ素化学への学問的貢献ばかりでなく、地元ヨウ素生産メーカーへの貢献も大きい。これらのことから、本研究で得られる成果は非常に意義深いと判断される。