Synthesis of Unexpected Bifunctionalized Thiazoles by Nucleophilic Attack on Allenyl Isothiocyanate
作者:Baker Jawabrah Al-Hourani、Frank Richter、Kai Vrobel、Klaus Banert、Marcus Korb、Tobias Rüffer、Bernhard Walfort、Heinrich Lang
DOI:10.1002/ejoc.201301851
日期:2014.5
reactivity is also seen with N-aminophthalimide. In the presence of azide salt, hydrazoic acid, or N,N-disubstituted hydroxylamines, however, allenyl isothiocyanate is converted into bifunctionalized thiazoles. We explain the formation of these products by nucleophilic addition at the isothiocyanato moiety followed by ring closure and an N–N or N–O cleavage reaction to generate short-lived 2-imino-5-methylidenethiazole
用各种亲核试剂处理异硫氰酸丙二烯酯会产生在 2 位具有官能团的 5-甲基噻唑。N-氨基邻苯二甲酰亚胺也观察到相同的反应模式。然而,在叠氮化物盐、偶氮酸或 N,N-二取代羟胺的存在下,异硫氰酸烯丙酯被转化为双官能化的噻唑。我们通过在异硫氰酸基部分亲核加成,然后闭环和 N-N 或 N-O 裂解反应来生成短寿命的 2-imino-5-methylidenethiazole 或 5-methylidenethiazol-2-one 来解释这些产物的形成。这些中间体通过加成反应被捕获以得到最终的杂环化合物。在 N,N-二取代羟胺的情况下,