1-芳基-2,2-二卤代乙酮肟与四氮化四硫(S 4 N 4)的反应:合成3-芳基-4-卤代-1,2,5-噻二唑的一般方法
摘要:
1-芳基-2,2-二氯-7、1-芳基-2,2-二溴-8、1-芳基-2-溴-2-氟-9和1-芳基-2-氯-2-氟-通过在室温下在EtOH中使相应的酮与盐酸羟胺反应来制备乙酮肟10。在1 H NMR光谱证据和1-(3-氯苯基)-2,2-二氯乙酮肟7f的X射线晶体学分析的基础上,对肟进行立体化学分配。1-芳基-2,2-二卤代乙酮肟与四氮化四硫反应,回流1,4-二恶烷,得到3-芳基-4-氯-1、3-芳基-4-溴-2和3-芳基-4 -氟-1,2,5-噻二唑3的产率分别为69-98、49-99和32-65%。提出了形成1,2,5-噻二唑的机理。
On-Water Synthesis of Dipyrromethanes via Bis-Hetero-Diels–Alder Reaction of Azo- and Nitrosoalkenes with Pyrrole
作者:Américo Lemos、Teresa Pinho e Melo、Nelson Pereira、Susana Lopes
DOI:10.1055/s-0033-1340300
日期:——
An unprecedented one-pot approach to 5-substituted dipyrromethanes based on the hetero-Diels-Alder reaction of azo- and nitrosoalkenes is described. The on-water reaction conditions led to the target compounds in higher yields with significantly shorter reaction times and simpler purification procedures than carrying out the reaction in dichloromethane or in the absence of solvent.