作者:Kanniyappan Gopi、Brijesh Rathi、Natesan Thirupathi
DOI:10.1007/s12039-010-0017-8
日期:2010.3
A one pot reaction involving sym N,N′-diarylthiourea and the respective arylamine in the presence of aq. KOH in nitrobenzene at ≥105°C afforded sym N,N′,N″-triarylguanidine in fair to good yield and the products have been characterized. Sym N,N′,N″-tri(4-tolyl)guanidine possesses (7) anti-anti conformation, sym N,N′,N″-tri(2-tolyl)guanidine (8) and sym N,N’,N″-tris(2,4-xylyl)guanidine (11) each possess anti-anti αβα conformation whereas sym N,N′,N″-tris(2-anisyl)guanidine possesses (9) syn-anti αββ conformation as determined by single crystal X-ray diffraction data. The observed conformations appear to result from a subtle balance between steric factor associated with the aryl substituent and multiple electronic factors namely n-π conjugation/negative hyperconjugation and non-covalent interactions in the crystal lattice.
在一锅反应中,以水合KOH为催化剂,在硝基苯中于≥105°C下,使对称N,N'-二芳基硫脲与相应的芳香胺反应,得到了产率尚可至良好的对称N,N',N"-三芳基胍。产物已经过表征。通过单晶X射线衍射数据确定,对称N,N',N"-三(4-甲苯基)胍具有反-反构型,对称N,N',N"-三(2-甲苯基)胍和N,N',N"-三(2,4-二甲苯基)胍分别具有反-反αβα构型,而对称N,N',N"-三(2-甲氧苯基)胍则具有顺-反αββ构型。这些构型的形成似乎是芳基取代基的立体因素与多个电子因素(包括n-π共轭/负超共轭以及晶格中的非共价相互作用)之间微妙平衡的结果。