Porphyrins with exocyclic rings. Part 25: synthesis of porphyrins with a fused cyclic ether subunit from tetrahydro-4H-pyan-4-one
作者:Breland E. Smith、Timothy D. Lash
DOI:10.1016/j.tet.2010.04.069
日期:2010.6
dihydropyran ring has been synthesized from commercially available 4-oxotetrahydropyran. The cyclicketone reacted with oximes derived from acetoacetate esters in the presence of zinc dust, sodium propionate, and propionic acid at 150–155 °C to give good yields of 5-oxatetrahydroindoles. A low yield of a benzo-fused analog was also obtained using 4-oxochromanone as the starting reagent. Reaction of the b-annelated
由可商购的4-氧四氢吡喃合成了具有稠合的二氢吡喃环的新型卟啉系统。在存在锌粉,丙酸钠和丙酸的条件下,在150–155°C的温度下,环状酮与衍生自乙酰乙酸酯的肟发生反应,从而获得了高产的5-氧杂四氢吲哚。使用4-氧代苯并二氢吡喃酮作为起始试剂也获得了低产率的苯并稠合类似物。b退火的吡咯与N的反应-氯代琥珀酰亚胺得到7-氯代衍生物,然后将它们与α-未取代的吡咯进行酸催化的缩合,得到由二氢吡喃部分连接的二吡咯产物。对二吡咯二苄基酯进行氢解得到相应的二羧酸,通过TFA-CH(OMe)3处理将其转化为二醛。在最佳条件下,MacDonald'2 + 2'与两种不同的二吡咯基甲烷缩合,生成的卟啉醚的收率为30–36%。该方法为卟啉冠醚结构的合成提供了初步研究。此外,通过仔细检查其在CDCl 3和DMSO- d 6中的质子NMR光谱,可以获得有关二氢吡喃连接的二吡咯构象的有深刻见解的结果。