Synthesis of Bridged Indigos and Their Thermoisomerization and Photoisomerization Behaviors

Photochromic derivatives of indigo: historical overview of development, challenges and applications

The importance of indigo dyes is constantly increasing with the evolution of novel textile materials and photochromic material technologies. The aim of this review article is to provide a comprehensive overview of the development of photochromic indigo derivatives from the first report on the photochromic N,N'-diacetylindigo in 1954 until now. We begin with the list of historical milestones in the development of photochromic indigo derivatives. Further, we provide a brief description of the synthetic procedures utilised to obtain indigo and its derivatives, outline the structural peculiarities, photophysical and photochemical properties of indigo and proceed with the detailed discussion of the photochromic indigo derivatives. Finally, we highlight the photochromism of the structural isomers of indigo (isoindigo and indirubin) and provide an overview of prospective applications of indigo photoswitches.

From cis-Lobeline to trans-Lobeline: Study on the Pharmacodynamics and Isomerization Factors

Lobeline is an alkaloid derived from the leaves of an Indian tobacco plant (Lobelia inflata), which has been prepared by chemical synthesis. It is classified as a partial nicotinic agonist and has a long history of therapeutic usage ranging from emetic and respiratory stimulant to tobacco smoking cessation agent. The presence of both cis and trans isomers in lobeline is well known, and many studies on the relationship between the structure and pharmacological activity of lobeline and its analogs have been reported. However, it is a remarkable fact that no studies have reported the differences in pharmacological activities between the two isomers. In this article, we found that different degrees of isomerization of lobeline injection have significant differences in respiratory excitatory effects in pentobarbital sodium anesthetized rats. Compared with cis-lobeline injections, the respiratory excitatory effect was significantly reduced by 50.2% after administration of injections which contained 36.9% trans-lobeline. The study on the influencing factors of isomerization between two isomers shown that this isomerization was a one-way isomerism and only converted from cis to trans, where temperature was the catalytic factor and pH was the key factor. This study reports a new discovery. Despite the widespread use of ventilators, first-aid medicines such as nikethamide and lobeline has retired to second line, but as a nonselective antagonist with high affinity for a4b2 and a3b2 nicotinic acetylcholine receptors (nAChRs). In recent years, lobeline has shown great promise as a therapeutic drug for mental addiction and nervous system disorders, such as depression, Alzheimer disease and Parkinson disease. Therefore, we suggest that the differences between two isomers should be concerned in subsequent research papers and applications.