loss of a CS moiety. The yields were close to 90% when the reaction was carried out in the presence of diethyl malonate. This compound was unambiguously identified by X-ray crystallography. Under the same conditions, 2-(methoxycarbonyl)phenyl isothiocyanate gave a quinazolinimine derivative instead which is likely to arise from cyclisation of an intermediate N,N′-diarylthiourea. The mechanism of formation
2-
氰基苯基异
硫氰酸酯与
乙酸锰(III)在
乙酸或
乙腈中反应,可得到新的缩聚
杂环化合物,得益于两个起始异
硫氰酸酯分子的结合而失去了CS部分,从而得到了新的缩合杂环。当反应在
丙二酸二乙酯存在下进行时,收率接近90%。通过X射线晶体学清楚地鉴定出该化合物。在相同条件下,2-(甲氧基羰基)苯基异
硫氰酸酯代替了
喹唑啉亚胺衍
生物,该衍
生物可能是由中间体N,N'-二芳基
硫脲的环化产生的。前一种化合物的形成机理可能涉及N,N的形成′-双(2-
氰基苯基)
硫脲,然后进行相应的环状
亚胺衍
生物的重排和自由基串联闭环。半假设计算也支持该假设。