一种制备2-(4 H -3,1-苯并噻嗪-4-基)乙酸衍生物和2-(2-硫代-1,2,3,4-四氢喹唑啉-4-基)乙酸的有效方法衍生物已经开发出来。3-(2-异硫氰酸根合苯基)丙酸衍生物与仲胺在室温下在甲醇中的反应生成相应的硫脲中间体,该中间体在回流温度下加热时,由于硫原子对1,4的丙烯部分的攻击而环化-addition方式,得到2-(2-二烷基氨基-4- ħ -3,1-苯并噻嗪-4-基)乙酸衍生物以一锅煮的。使用伯胺代替仲胺的类似序列提供了2- [3-烷基(或芳基)-2-硫代-1,2,3,4-四氢喹唑啉-4-基]乙酸衍生物。 4 H -3,1-苯并噻嗪-2-硫代-1,2,3,4-四氢喹唑啉-3-(2-异硫氰酸根合苯基)丙酸-硫脲-1,4-加成
Synthesis of thiazolo[2,3-<i>b</i>]quinazoline derivatives <i>via</i> base-promoted cascade bicyclization of <i>o</i>-alkenylphenyl isothiocyanates with propargylamines
A highly efficient cascade bicyclization reaction of o-alkenylphenyl isothiocyanates with propargylamines has been developed, which affords a series of thiazolo[2,3-b]quinazolines in good to excellent yields by using K2CO3 as a base in MeCN at 80 °C. This method is transition-metal-free and operationally simple with broad functional group tolerance. Mechanistically, 6-exo-trig hydroamination followed