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Iodine/Copper(I)‐Catalyzed Direct Annulation of N ‐Benzimidazolyl Amidines with Aldehydes for the Synthesis of Ortho ‐Fused 1,3,5‐Triazines
Author(s) -
Wang Manman,
Meng Yinggao,
Wei Wei,
Wu Jie,
Yu Wenquan,
Chang Junbiao
Publication year - 2018
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201701126
Subject(s) - chemistry , annulation , amidine , catalysis , iodine , iodide , lewis acids and bases , methyl iodide , copper , combinatorial chemistry , organic chemistry , toluene , medicinal chemistry
A direct annulation reaction of N ‐benzimidazolyl amidines with aldehydes has been established and allows the synthesis of ortho ‐fused 1,3,5‐triazine derivatives. The N ‐benzimidazolyl amidine substrates are readily accessible by the addition of 2‐aminobenzimidazoles to the corresponding nitriles. In the presence of molecular iodine and copper iodide, cyclization of benzimidazolyl amidines with various aldehydes in toluene under reflux followed by oxidation with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) gives the corresponding products. In this reaction, iodine acts more as a Lewis acid catalyst than as an oxidant. This synthetic process is insensitive to air and operationally simple, and provides facile access to a variety of novel 1,3,5‐triazino[1,2‐ a ]benzimidazoles and related heterocycles.