Current Organic Chemistry - Volume 23, Issue 1, 2019

Hydrophobic proteins, as one of the cellular protein classifications, play an essential function in maintaining the normal life cycle of living cells. Researches on the structure and function of hydrophobic proteins promote the exploration of the causes of major diseases, and development of new therapeutic agents for disease treatment. However, the poor water solubility of hydrophobic proteins creates problems for their preparation, separation, characterization and functional studies. The temporary solubilizing tags are considered a practical strategy to effectively solve the poor water solubility problem of hydrophobic proteins. This strategy can significantly improve the water solubility of hydrophobic peptides/proteins, making them like water-soluble peptides/proteins easy to be purified, characterized. More importantly, the temporary solubilizing tags can be removed after protein synthesis, so thus the structure and function of the hydrophobic proteins are not affected. At present, temporary solubilizing tags have been successfully used to prepare many important hydrophobic proteins such as membrane proteins, lipoproteins and chaperones. In this review, we summarize the recent researches and applications of temporary solubilizing tags.

Hypervalent iodine reagents have been widely used in the construction of many important building blocks and privileged scaffolds of bioactive natural products. This review article aims to briefly discuss strategies that have used hypervalent iodine reagents as oxidants to synthesize spiroheterocyclic compounds and to stimulate further study for novel syntheses of spiroheterocyclic core structures using hypervalent iodine reagents under metal-free conditions.

Natural cyclic peptides are conformationally constrained notable biomolecules and reveal several drug-like properties such as high binding affinity, metabolic stability, target selectivity, bioavailability, low toxicity and flexibility. They have attracted a lot of attention as alternative sources of new drugs to traditional small molecules in drug discovery. Compared to classical medicines, cyclic peptides with a novel mechanism of action are attractive for their potential therapeutic applications particularly for cancer therapy and several diseases caused by resistant and non-resistant bacteria, virus, and fungi. Herein, we provide an overview of the naturally occurring biologically active cyclic peptide therapeutic landscape, including promising candidates, which are under trial in different stages for future and/or clinically used drugs against different diseases. This will certainly be an essential resource for upcoming and existing researchers and scientists within industry and academia in medicinal, bioorganic, and natural product chemistry.

Due to special properties of ILs (ionic liquids) like their wide liquid range, good solvating ability, negligible vapour pressure, non-inflammability, environmentfriendly medium, high thermal stability, easy recycling and rate promoters etc. they are used in organic synthesis. Therefore, ionic liquids have attracted the attention of chemists and act as a catalyst and reaction medium in organic reaction with high activity. There is no doubt that ionic liquids have become a major subject of study for modern chemistry. More publications in the field have been observed each year, although there is some evidence that this is beginning to plateau at approximately 3500 papers each year. They have been the subject of several major reviews and books, dealing with different applications and aspects of their behavior. Highly efficient methods are explored for the preparation of six-membered two nitrogen-containing heterocycles with the application of IL as a catalyst and reaction medium from 1893 to 2018.

Tri-carbonylated oxiranes were efficiently synthesized by condensing a vicinal tricarbonyl compound with α-bromoketones in the presence of a base. This protocol was applicable to α–bromo-β-keto esters to create tetra-carbonylated oxiranes, from which trifunctionalized bromoalkene was competitively formed. The ratio of these compounds was influenced by the solvent and reaction temperature.