Metal-Free Synthesis of 2-<i>N</i>,<i>N</i>-Dialkylaminobenzoxazoles Using Tertiary Amines as the Nitrogen Source
作者:Mookda Pattarawarapan、Dolnapa Yamano、Nitaya Wiriya、Wong Phakhodee
DOI:10.1021/acs.joc.9b00797
日期:2019.5.17
The unprecedented reaction of tertiary amines with 2(3H)-benzoxazolones has been investigated. In the presence of the Ph3P–I2 reagent system, the reaction of both acyclic and cyclic aliphatic tertiary amines led to the formation of 2-N,N-dialkylaminobenzoxazoles with the selective cleavage of an alkyl group. Especially, N-(2-iodoethyl)piperazinyl derivatives were rapidly produced in good yields when
已研究了叔胺与2(3 H)-苯并恶唑酮的空前反应。在Ph 3 P–I 2试剂体系的存在下,无环和环状脂族叔胺的反应均导致2- N,N-二烷基氨基苯并恶唑的形成,并选择性地裂解了烷基。特别地,当使用DABCO作为氮源时,N-(2-碘乙基)哌嗪基衍生物以高收率快速生产。仅在底物的亲核性超过胺的亲核性的情况下,苯并恶唑酮的竞争性自缩合才优先进行。31 P 11 H-NMR研究表明涉及芳氧基phosph中间体和/或可能的2-碘苯并恶唑,其激活苯并恶唑酮的C-2位朝亲核芳族取代。