Current Organic Chemistry - Volume 23, Issue 6, 2019

Recent years have witnessed a fast development of solid phase synthetic pathways, a variety of solid-supported reagent and its applications in diverse synthetic strategies and pharmaceutical applicability’s. Polymer-supported triphenylphosphine is getting a lot of applications owing to the speed and simplicity in the process. Furthermore, ease of recyclability and reuse of polymer-supported triphenylphosphine added its advantages. This review covers a wide range of useful organic transformations which are accomplished using cross-linked polystyrene-supported triphenylphosphine with the aim of giving renewed interest in the field of organic and medicinal-combinatorial chemistry.

The solid-phase synthesis (SPS) of phosphorus-containing compounds is based mainly on the fact that the chemical process is conducted in a two-phase system. One of the components is connected via covalent bonds to a solid support, which is in general an insoluble polymer, representing the solid phase of the process. The other components involved into the process are solubilized in a solution. The method is suitable to be applied to almost any organic compounds. A common example of using solid-phase synthesis is for obtaining products nucleotide containing, similar to nucleic acids. During the whole process, the nucleotide is always on the solid phase, after the condensation reaction, except for the last step, when the synthesis is already finished. Then, the product is released and separated very easily by filtration. The obtained polymer-oligonucleotide product can participate further in condensation reactions as well. Other important biomolecules synthesized by solid-phase approach during the last decades are nucleoside di- and triphosphates, nucleoside diphosphate sugars and dinucleoside polyphosphates. Those products are precursors of deoxysugars, aminodeoxysugars, uronic acids or glycoconjugates, and are also necessary for DNA and RNA synthesis. The use of the solid-phase method in the context of immobilized oligomers is of great interest nowadays. The solid-phase synthesis offers many advantages in comparison with the conventional solution-phase method, because it takes much less time, it is highly stereoselective, the products are separated and purified usually by a simple filtration or decantation, solvents with high boiling points could be used, the whole process is based on solid polymer support and the obtained compounds should not be isolated.

The use of transition-metal nanoparticles in catalysis has attracted much interest, and their use in carbon-carbon coupling reactions such as Suzuki, Heck, Sonogashira, Stille, Hiyama, and Ullmann coupling reactions constitutes one of their most important applications. The transition-metal nanoparticles are considered as one of the green catalysts because they show high catalytic activity for several reactions in water. This review is devoted to the catalytic system developed in the past 10 years in transition-metal nanoparticles-catalyzed carbon-carbon coupling reactions such as Suzuki, Heck, Sonogashira, Stille, Hiyama, and Ullmann coupling reactions in water.

Background: In the past decades, Chinese herbal medicine has attracted worldwide attention because they contain a variety of active ingredients which are beneficial to human health. As a result, there is a growing interest in the extraction of these substances. However, traditional extraction methods not only need a large amount of extractant, but are also time-consuming, moreover, the extraction efficiency is extremely poor and tedious purification steps are required to purify the crude extract. Thus, researchers hope to find an alternative method for the extraction of these components and the aqueous two-phase system (ATPS) seems to be one. Objective: This review focuses on introducing the properties of the aqueous two-phase system and summarizing the application of ATPS in the extraction of natural products. Meanwhile, this review also provided a guideline to researchers who wish to design a suitable ATPS for a specific target and how to amplify it to industrial-scale.

Pyrazolo[1,5-a]pyrimidines are fused N-heterocyclic systems of a pyrazole. They are considered as a key structural motif in many vital applications, such as medicinal, pharmaceuticals, pesticides, dyes and pigments. Their synthetic routes have escalated dramatically in the last decades. The current review is a recent synthetic survey of pyrazolo[ 1,5-a]pyrimidines and their applications until recently.