抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

The Huisgen 1,3-dipolar cycloaddition reaction of organic azides and alkynes has gained considerable attention in recent years due to the introduction in 2001 of Cu(1) catalysis by Tornoe and Meldal, leading to a major improvement in both rate and regioselectivity of the reaction, as realized independently by the Meldal and the Sharpless laboratories. The great success of the Cu(1) catalyzed reaction is rooted in the fact that it is a virtually quantitative, very robust, insensitive, general, and orthogonal ligation reaction, suitable for even biomolecular ligation and in vivo tagging or as a polymerization reaction for synthesis of long linear polymers. The triazole formed is essentially chemically inert to reactive conditions, e.g. oxidation, reduction, and hydrolysis, and has an intermediate polarity with a dipolar moment of ∼5 D. The basis for the unique properties and rate enhancement for triazole formation under Cu(1) catalysis should be found in the high ∆G of the reaction in combination with the low character of polarity of the dipole of the noncatalyzed thermal reaction, which leads to a considerable activation barrier. In order to understand the reaction in detail, it therefore seems important to spend a moment to consider the structural and mechanistic aspects of the catalysis. The reaction is quite insensitive to reaction conditions as long as Cu(1) is present and may be performed in an aqueous or organic environment both in solution and on solid support.

Cu-catalyzed azide-alkyne cycloaddition.

The direct functionalization of C-H bonds in organic compounds has recently emerged as a powerful and ideal method for the formation of carbon-carbon and carbon-heteroatom bonds. This Review provides an overview of C-H bond functionalization strategies for the rapid synthesis of biologically active compounds such as natural products and pharmaceutical targets.

C-H bond functionalization: emerging synthetic tools for natural products and pharmaceuticals

Functionalizing traditionally inert carbon–hydrogen bonds represents a powerful transformation in organic synthesis, providing new entries to valuable structural motifs and improving the overall synthetic efficiency. C–H bond activation, however, often necessitates harsh reaction conditions that result in functional group incompatibilities and limited substrate scope. An understanding of the reaction mechanism and rational design of experimental conditions have led to significant improvement in both selectivity and applicability. This critical review summarizes and discusses endeavours towards the development of mild C–H activation methods and wishes to trigger more research towards this goal. In addition, we examine select examples in complex natural product synthesis to demonstrate the synthetic utility of mild C–H functionalization (84 references).

Towards mild metal-catalyzed C–H bond activation

C-H bonds are ubiquitous in organic compounds. It would, therefore, appear that direct functionalization of substrates by activation of C-H bonds would eliminate the multiple steps and limitations associated with the preparation of functionalized starting materials. Regioselectivity is an important issue because organic molecules can contain a wide variety of C-H bonds. The use of a directing group can largely overcome the issue of regiocontrol by allowing the catalyst to come into proximity with the targeted C-H bonds. A wide variety of functional groups have been evaluated for use as directing groups in the transformation of C-H bonds. In 2005, Daugulis reported the arylation of unactivated C(sp(3))-H bonds by using 8-aminoquinoline and picolinamide as bidentate directing groups, with Pd(OAc)2 as the catalyst. Encouraged by these promising results, a number of transformations of C-H bonds have since been developed by using systems based on bidentate directing groups. In this Review, recent advances in this area are discussed.

Catalytic Functionalization of C(sp2) ? H and C(sp3) ? H Bonds by Using Bidentate Directing Groups

Provided are compositions, articles and methods that relate to promoting neurogenesis or neuroregeneration in mammalian nervous system. Embodiments relate to use of groups of compounds that contain Crizotinib (Cri), Flurbiprofen, Lithium Chloride (Li), Vitamin C (VC), Ceritinib (Cer) or Pirfenidone (PFD). In certain implementations glial cells are converted into functional neurons.

Chemical reprogramming of human glial cells into neurons with small molecule cocktail

Generally, good yields are obtained for a broad scope of substrates and the reaction is tolerant to air and moisture.

Facile Benzo‐Ring Construction via Palladium‐Catalyzed Functionalization of Unactivated sp3 C—H Bonds under Mild Reaction Conditions.

A visible-light-promoted and radical-mediated strategy for the site-specific cleavage of C(sp3)-C(sp3) bonds in ethers is reported. Different cyclic and linear alkyl ethers are converted into benzoylated acetals and aldehydes or...

Hypervalent-iodine Promoted Selective Cleavage of C(sp3)-C(sp3) Bonds in Ethers

This article traces the development of catalytic, intramolecular dehydrogenative C–H amination (IDCA) reactions. Over the last 10 years, effective syntheses of carbazoles, indolines and oxindoles via palladium-catalyzed sp2 intramolecular dehydrogenative C–H amination reactions have been realized. While the corresponding amination reactions of sp3 C–H bonds are more challenging, syntheses of pyrrolidines, azetidines, β-lactams and even aziridines via this manifold have been reported. 1 	Introduction 2 	Intramolecular Aminations of C(sp2)–H Bonds 3 	Intramolecular Aminations of C(sp3)–H Bonds 4 	Conclusion

Syntheses of Nitrogen-Containing Heterocycles via Palladium-Catalyzed Intramolecular Dehydrogenative C—H Amination

Substitution of the picolinamide moiety by picolinic acid, N-methyl picolinamide, benzamide, or sulfonamides results in no reaction.

Gong Chen

Papers

Chemical reprogramming of human glial cells into neurons with small molecule cocktail

Facile Benzo‐Ring Construction via Palladium‐Catalyzed Functionalization of Unactivated sp3 C—H Bonds under Mild Reaction Conditions.

Hypervalent-iodine Promoted Selective Cleavage of C(sp3)-C(sp3) Bonds in Ethers

Syntheses of Nitrogen-Containing Heterocycles via Palladium-Catalyzed Intramolecular Dehydrogenative C—H Amination

Copper‐Catalyzed Carboxamide‐Directed ortho Amination of Anilines with Alkylamines at Room Temperature.