Singh Jagmeet, Singh Abhijeet, Nath Mahendra
Department of Chemistry, Faculty of Science, University of Delhi, Delhi 110 007, India.
Org Biomol Chem. 2024 May 29;22(21):4369-4377. doi: 10.1039/d4ob00598h.
A divergent one-pot domino strategy for the synthesis of nickel(II) and copper(II) β-thiophene-fused 5,10,15,20-tetraarylporphyrins was developed through a thiol-Michael addition of thioglycolic/thiolactic acid to the corresponding 2-iminoporphyrins, formed after the reaction of nickel(II) and copper(II) 2-formyl-5,10,15,20-tetraarylporphyrins with sterically hindered -butylamine in 1,2-dichloroethane at 80 °C. Interestingly, the reaction of 2-formylporphyrins with comparatively less sterically hindered primary amines and thioglycolic acid afforded a mixture of β-substituted porphyrinic thiazolidinones and β-thiophene-fused porphyrins. A similar one-pot thiol-Michael protocol was applied to construct a novel free-base thieno[2,3-]--tetrakis(4-methoxyphenyl)porphyrin, which underwent zinc insertion by using zinc acetate in a CHCl-MeOH mixture and afforded zinc(II) β-thiophene-fused -tetrakis(4-methoxyphenyl)porphyrin in an appreciable isolated yield. On photophysical evaluation, these new porphyrins displayed a modest bathochromically shifted electronic absorption in contrast to -tetraarylporphyrin building blocks.
通过巯基乙醇酸/巯基乳酸与相应的2-亚氨基卟啉进行硫醇-迈克尔加成反应，开发了一种用于合成镍（II）和铜（II）β-噻吩稠合的5,10,15,20-四芳基卟啉的发散性一锅多米诺策略。2-甲酰基-5,10,15,20-四芳基镍（II）和铜（II）卟啉与空间位阻叔丁胺在80℃的1,2-二氯乙烷中反应后形成该2-亚氨基卟啉。有趣的是，2-甲酰基卟啉与空间位阻较小的伯胺和巯基乙醇酸反应得到β-取代的卟啉噻唑烷酮和β-噻吩稠合卟啉的混合物。应用类似的一锅硫醇-迈克尔方法构建了一种新型的游离碱噻吩并[2,3-b] - 四（4-甲氧基苯基）卟啉，其通过在CHCl3-MeOH混合物中使用乙酸锌进行锌插入反应，并以可观的分离产率得到锌（II）β-噻吩稠合 - 四（4-甲氧基苯基）卟啉。在光物理评估中与 - 四芳基卟啉结构单元相比，这些新型卟啉显示出适度的红移电子吸收。
