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It is important to find more effective and safer immunosuppressants, because clinically used immunosuppressive agents have significant side effects. A series of N-substituted iminosugar derivatives were designed and synthesized, and their immunosuppressive effects were evaluated by the CCK-8 assay. The results revealed that iminosugars 10 e and 10 i, that is, (3R,4S)-1-(4-heptyloxylphenylethyl)pyrrolidine-3,4-diol and (3R,4S)-1-[2-(2-chloro-4-(p-tolylthio)-phenyl-1-yl)ethyl]pyrrolidine-3,4-diol, respectively, exhibited the strongest inhibitory effects on mouse splenocyte proliferation (IC50 =2.16 and 2.48 μm, respectively), whereas the iminosugars containing an amide group near the hydrophilic head (compounds 10 j-n) exhibited no inhibitory effects. Further studies revealed that the inhibitory effects on splenocyte proliferation may have come from the suppression of both IFN-γ and IL-4 cytokines. Our results suggest that synthetic iminosugars, especially compounds 10 e and 10 i, hold potential as immunosuppressive agents.

An efficient method for the construction of cyclopropane-fused dihydroquinolines was established by a novel Povarov-type three-component reaction of aromatic aldehydes, anilines and cyclopropenes in the presence of trifluoromethanesulfonic acid. The reaction proceeded in a regioselective and diastereoselective manner. Furthermore, the dihy-droquinolines were smoothly converted to benzazepine derivatives via a ring opening/isomerization sequence, further expanding the synthetic scope.

Crystal engineering of the nbo metal-organic framework (MOF) platform MOF-505 with a custom-designed azamacrocycle ligand (1,4,7,10-tetrazazcyclododecane-N,N',N'',N'''-tetra-p-methylbenzoic acid) leads to a high density of well-oriented Lewis active sites within the cuboctahedral cage in MMCF-2, [Cu2(Cu-tactmb)(H2O)3(NO3)2]. This MOF demonstrates high catalytic activity for the chemical fixation of CO2 into cyclic carbonates at room temperature under 1 atm pressure.

The 3-butenyloxycarbonyl group can be introduced into carbohydrates such as (I) under mild conditions.

A monoselective synthesis of aryl-C-Δ1,2-glycosides from 1-iodoglycals via palladium-catalyzed ortho-C–H activation of N-quinolyl benzamides has been developed. An amino acid derivative was used as a crucial ligand to improve the yield and monoselectivity of the coupling reaction. The utility of this protocol was demonstrated by a concise synthesis of key moieties of some natural products.

An efficient and facile synthesis of phytosphingosine and dihydrosphingosine derivatives is described with less steps and in improved overall yield (66–72%) starting from commercially available tri-O-benzyl-D-galactal. The key steps include Wittig reaction, Mitsunobu transformation, reduction, and deprotection.

An efficient method for the construction of cyclopropane-fused dihydroquinolines was established by a novel Povarov-type three-component reaction of aromatic aldehydes, anilines and cyclopropenes in the presence of trifluoromethanesulfonic acid. The reaction proceeded in a regioselective and diastereoselective manner. Furthermore, the dihy-droquinolines were smoothly converted to benzazepine derivatives via a ring opening/isomerization sequence, further expanding the synthetic scope.

The creation and development of nonnatural peptidomimetics has become an area of increasing significance in bioorganic and chemical biology. A wide range of new peptide mimics with novel structures and functions are urgently needed to be explored in order to identify potential drug candidates and targeted probes, and to study protein functions. AApeptides are a new class of peptide mimics based on chiral PNA backbone. They are resistant to proteolytic degradation and have limitless potential for diversification. They have been found to have a wide variety of biological applications including cellular translocation, disruption of protein-protein interactions, formation of nanostructures, antimicrobial activity, etc. The synthesis of AApeptides is modular and straightforward. In this chapter, methods for the synthesis of AApeptides (including different subclasses) are described.

Antibiotic resistance is an increasing public health concern around the world, and is recognized as one of the greatest threats facing humankind in the 21st century. Natural antimicrobial peptides (AMPs) are small cationic amphiphilic peptides found in virtually all living organisms, and play a key role in the defense against bacterial infections. Compared with conventional antibiotics, which target specific metabolic processes, AMPs are able to adopt globally amphipathic conformations, and kill bacteria through disruption of their membranes. As such, AMPs do not readily induce drug-resistance. However, AMPs are associated with intrinsic drawbacks such as low-to-moderate activity, susceptibility to enzymatic degradation, and inconvenience for optimization. Recently, we have developed a new class of peptidomimetics termed “AApeptides”. Such peptide mimics are highly resistant to protease degradation and are straightforward for chemical diversification and development. Our current studies show that AApeptides with globally amphipathic structures can mimic the bactericidal mechanism of AMPs, and display potent and broad-spectrum activity against both Gram-positive and -negative multi-drug-resistant bacteria. In this review, we summarize our current findings of antimicrobial AApeptides, and discuss potential future directions on the development of more potent and specific analogues.

NaHSO 4 ·SiO 2 was used as an efficient heterogeneous catalyst for both the formation and the cleavage of benzylidene -acetals. This catalyst is compatible with many functional or protective groups. Under different solvent systems, either the formation or the cleavage of benzylidene acetals was carried out smoothly in -excellent yields and with good chemoselectivity.