[Cloning and bioinformatics analysis of ß-amyrin synthase in Dipsacus asper].

Dipsaci Radix is one of the commonly used Chinese medicinal materials in China, with a long history. It has the medicinal activities of nourishing liver and kidney, recovering from broken sinews, and treating bone fracture. Triterpenoid saponins are the main functional ingredients of Dipsacus asper. ß-Amyrin synthases(ß-AS) as a superfamily of oxidosqualene cyclases(OSCs) can catalyze the construction of the skeleton structure of oleanane-type triterpenoid saponins. There are only a few studies about the ß-AS in D. asper, and the catalytic mechanism of this enzyme remains to be explored. To enrich the information of ß-AS, according to the transcriptome sequencing results, we cloned DaWß-AS gene from D. asper into a specific vector for heterologous expression in Escherichia coli. In the meantime, real-time PCR was performed to analyze the relative expression of DaWß-AS in four different tissues of D. asper. The results of RT-qPCR showed DaWß-AS had the highest expression level in leaves. Bioinformatics results indicated that DaWß-AS had a conserved domain of PLN03012 superfamily, belonging to the cl31551 superfamily. There was no transmembrane domain or signal peptide in DaWß-AS. This study provides a scientific basis for revealing the biological pathways of triterpenoid saponins in D. asper, which will facilitate the biosynthesis of the associated saponins and afford reference for the cultivation and development of high-quality resources of D. asper.

A visible-light-induced chemoselective radical/oxidative addition domino process to access α-chloro and α-alkoxy aryl ketones.

A visible-light-induced radical-triggered chemoselective domino process to access α,α-di-functionalized ketones under mild conditions has been developed. This protocol provides a direct approach to synthesize α-chloro or α-alkoxy aryl ketones based on the electronic properties of the substrates. The reaction can tolerate a variety of functional groups to afford the corresponding products in moderate to good yields.

Synthesis of highly functionalized macrocycles by tandem multicomponent reactions and intramolecular Sonogashira cross-coupling.

An efficient chemoselective process for the synthesis of 14- and 15-membered triazole-containing macrocycle compounds has been developed through the combination of two multicomponent reactions and an intramolecular Sonogashira cross-coupling reaction.

Chemoselective preparation of 1,2,3-triazole-isoxazole bisfunctional derivatives and their application in peptidomimetic synthesis.

A novel kind of bisfunctional nitrogen heterocycle containing both 1,2,3-triazole and isoxazole scaffolds has been prepared. The protocol utilized alkynyl substituted amines as the bifunctional linkers to combine a copper-free triazole synthesis with a hypervalent iodine-mediated isoxazole cycloaddition through a chemoselective process. This method has also been exemplified in the construction of bisfunctional-modified peptidomimetics by combining three reactions in a sequential procedure. This straightforward metal free process may find biological applications. In addition, all of the compounds were analysed by Lapinski's rule-of-five which is expected to help drug discovery.

Copper-free route to triazole-modified peptidomimetic by the combination of two multicomponent reactions in one pot.

An efficient copper-free protocol for the synthesis of 5-methyl-1H-1,2,3-triazole-modified peptidomimetics through the combination of Ugi four-component reaction with a three-component cycloaddition, has been developed. The copper-free straightforward process is suitable for drug discovery. The chemoselective preparation of 1,4-disubstituted, triazole-modified peptidomimetics by using alkynyl substituted amines may have potential biological and synthetic application. At last, a "Lapinski type" analysis of the physical properties was performed, which is expected to help drug discovery.