Murata Yuki, Kawakubo Masato, Maruyama Ayumi, Matsumura Mio, Yasuike Shuji
School of Pharmaceutical Sciences, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan.
Molecules. 2025 Jan 15;30(2):319. doi: 10.3390/molecules30020319.
Oxazole, a versatile and significant heteroarene, serves as a bridge between synthetic organic chemistry and applications in the medicinal, pharmaceutical, and industrial fields. Polycyclic aromatic compounds with amino groups substituted at the 2-position of an oxazole, such as 2-aminonaphthoxazoles, are expected to be functional probes, but their synthetic methods are extremely limited. Herein, we describe electrochemical reactions of 3-amino-2-naphthol or 3-amino-2-anthracenol and isothiocyanates in DMSO, using a graphite electrode as an anode and a platinum electrode as a cathode in the presence of potassium iodide (KI), which afford -arylnaphtho- and -arylanthra[2,3-]oxazol-2-amines via cyclodesulfurization. This reaction is the first example of synthesis of 2-aminoxazole-based polycyclic compounds using an electrochemical reaction. An examination of the spectroscopic properties of polycyclic oxazoles revealed that the λ value of the tetracyclic oxazoles was redshifted relative to that of the tricyclic oxazoles. Moreover, synthesized naphthalene/anthracene-fused tricyclic and tetracyclic oxazoles exhibited extended π-conjugated skeletons and fluoresced in the 340-430 nm region in chloroform.
恶唑是一种用途广泛且重要的杂芳烃，它在合成有机化学与医药、制药及工业领域的应用之间架起了一座桥梁。在恶唑的2位上被氨基取代的多环芳香化合物，如2-氨基萘并恶唑，有望成为功能性探针，但其合成方法极为有限。在此，我们描述了在二甲基亚砜（DMSO）中，以石墨电极为阳极、铂电极为阴极，在碘化钾（KI）存在的条件下，3-氨基-2-萘酚或3-氨基-2-蒽酚与异硫氰酸酯的电化学反应，该反应通过环脱硫反应生成 -芳基萘并恶唑和 -芳基蒽并[2,3-]恶唑-2-胺。此反应是利用电化学反应合成基于2-氨基恶唑的多环化合物的首例。对多环恶唑光谱性质的研究表明，四环恶唑的λ值相对于三环恶唑发生了红移。此外，合成的萘/蒽稠合三环和四环恶唑展现出扩展的π共轭骨架，并在氯仿中于340 - 430 nm区域发出荧光。
