Current Organic Chemistry - Volume 23, Issue 15, 2019

C-C cross-couplings constitute the largest diversity of organic reactions of chemical, biomedical, and industrial significance. They are also among the most frequently encountered reactions used in the synthesis of numerous drugs and relevant pharmaceutical substances. Development of an easily accessed, efficient, stable, and low cost catalyst is an attractive area of research in such kind of organic synthesis. This review highlights the remarkable and recent achievements made recently in the synthesis and use of palladium(II) complexes catalysts, that are based on heterocycles as ligands in their constitution, in the Suzuki-Miyaura cross-coupling.

Protein methylation is an important and reversible post-translational modification that regulates many biological processes in cells. It occurs mainly on lysine and arginine residues and involves many important biological processes, including transcriptional activity, signal transduction, and the regulation of gene expression. Protein methylation and its regulatory enzymes are related to a variety of human diseases, so improved identification of methylation sites is useful for designing drugs for a variety of related diseases. In this review, we systematically summarize and analyze the tools used for the prediction of protein methylation sites on arginine and lysine residues over the last decade.

Lots of cold-adapted organisms could produce antifreeze proteins (AFPs) to counter the freezing of cell fluids by controlling the growth of ice crystal. AFPs have been found in various species such as in vertebrates, invertebrates, plants, bacteria, and fungi. These AFPs from fish, insects and plants displayed a high diversity. Thus, the identification of the AFPs is a challenging task in computational proteomics. With the accumulation of AFPs and development of machine meaning methods, it is possible to construct a high-throughput tool to timely identify the AFPs. In this review, we briefly reviewed the application of machine learning methods in antifreeze proteins identification from difference section, including published benchmark dataset, sequence descriptor, classification algorithms and published methods. We hope that this review will produce new ideas and directions for the researches in identifying antifreeze proteins.

Carbazole derivatives have extensive π–conjugation due to which they are excellent organic electronics and show semiconducting properties. Carbazole-based various materials are important candidates due to their excellent redox and luminescent properties and good thermal and environmental stability, therefore, carbzole nucleus was chosen for exploring these properties. The title compound was recrystallized from a methanol solution in orthorhombic space group P 212121 with unit cell dimensions a = 9.663(2), b = 10.764(3), c =18.139(4), V= 1886.7(7) Å3, Z=4. Density functional theory (DFT) calculations have been carried out for the title compound using the 6-31G(d) basis set. The calculated results showed that the theoretically predicted geometry can well reproduce the experimentally calculated structural parameters.

The asymmetric Friedel-Crafts reaction of indoles with imines provides a direct approach for the enantioselective construction of 3-indolyl methanamine derivatives. In this paper, a series of thiourea/ urea-tertiary amine derivatives have been used to catalyze the asymmetric F-C reaction of indoles with N-tosylimines. The effect of solvent, temperature and catalyst loading amount were investigated. the optimized conditions were determined to be toluene as the solvent with a 5 mol% loading of Takemoto's catalyst 1c at rt. A wide range of substituted indoles and imines were evaluated to explore the scope and general applicability of this reaction. The enantioselectivities were obviously affected by the position of the substituents on the phenyl ring of imines. 4- electron-donating substituted imines appeared to favor higher enantioselectivities. Moreover, indoles containing either electron-donating groups or electron-withdrawing groups were then investigated for the reaction with imines. In all cases, high yields and excellent enantioselectivities could be achieved. Of all the different substrates, the reaction of the 5-OMe substituted indole with 4-chloride substituted imine afforded an optimal yield and enantiomeric excess. Under the screened optimal condition, optically active 3-indolyl-methanamines were obtained in good yields (70-90%) with high enantioselectivities (up to 98%ee). The catalyst type and the substrate scope were broadened in this methodology.