A lot of chiral stationary phases (CSPs) have been introduced for the purpose of analytical and preparative separations of enantiomers. CSPs based on proteins and glycoproteins have unique properties among those CSPs. This review article deals with the preparation of CSPs based on proteins and glycoproteins, their chiral recognition properties and mechanisms, focusing on the CSPs investigated in our group. The dealt proteins and glycoproteins are including bovine serum albumin, human serum albumin, lysozyme, pepsin, human α1-acid glycoprotein (AGP), chicken ovomucoid and chicken ovoglycoprotein (named chicken AGP).
The ligand-binding
sites of F1*S and A variants of human α-acid glycoprotein (hAGP), and chicken AGP were completely
different. The former sites were located in lobs I-III including W122, while
the later ones were located near W26. Both (R)- and (S)-benzoin
were docked onto a cavity of the generated model structure of cAGP. In addition
to hydrophobic interactions, some of hydrogen bonding interactions worked for
chiral recognition of (R)-
and (S)-benzoin. (R)-Benzoin
bound to cAGP more tightly than (S)-benzoin. The elution order of benzoin enantiomers on
chiral stationary phases based on cAGP in LC were consistent with the docking
results.
The development of structurally novel nucleoside analogues is an active area in medicinal chemistry, since these drugs have proven clinical efficacy for decades. Azanucleosides are nucleoside analogues in which the sugar moieties are composed of nitrogen-containing rings or chains. In recent years, many azanucleosides have demonstrated therapeutic potential. In this short review, we describe recent advancements in azanucleosides, which may translate in a better understanding of the molecular design, biological activity, structure–activity relationship, and their related mechanism of action. The information summarized in this paper should encourage medicinal chemists in their future efforts to create more potent and effective chemotherapeutic agents.
1,2-Naphthoquinone (2-NQ) is a nucleophile acceptor that non-selectively makes covalent bonds with cysteine residues in various cellular proteins, and is also found in diesel exhaust, an air pollutant. This molecule has rarely been considered as a pharmacophore of bioactive compounds, in contrast to 1,4-naphthoquinone. We herein designed and synthesized a compound named N-(7,8-dioxo-7,8-dihydronaphthalen-1-yl)-2-methoxybenzamide (MBNQ), in which 2-NQ was hybridized with the nuclear factor-κB (NF-κB) inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) as a nucleophile acceptor. Although 50 µM MBNQ did not inhibit NF-κB signaling, 10 µM MBNQ induced cell death in the lung cancer cell line A549, which was insensitive to 2-NQ (10 µM). In contrast, MBNQ was less toxic in normal lung cells than 2-NQ. A mechanistic study showed that MBNQ mainly induced apoptosis, presumably via the activation of p38 mitogen-activated protein kinase (MAPK). Collectively, the present results demonstrate that the introduction of an appropriate substituent into 2-NQ constitutes a new biologically active entity, which will lead to the development of 2-NQ-based drugs.
The first total syntheses of natural phenanthrene alkaloids, namely, uvariopsamine (1), noruvariopsamine (2), 8-hydroxystephenanthrine (3), 8-methoxyuvariopsine (4), thalihazine (5), and secophoebine (6), have been realized. In addition, their in vitro antimalarial activity against the multidrug-resistant K1 strain of Plasmodium falciparum and in vitro cytotoxic activity against the human nasopharynx carcinoma (KB), small cell lung cancer (NCI-H187), and breast cancer (MCF7) human cancer cell lines were investigated. All the phenanthrene alkaloids showed significant antiplasmodial activity (IC50 1.07–7.41 µM), and most compounds displayed low to no toxicity against the three cancer cell lines tested. Particularly, 3 exhibited the best antimalarial activity with an IC50 value of 1.07 µM, no toxicity to NCI-H187 (IC50 > 50 µM), and low toxicity against KB (IC50 24.53 µM) and MCF7 (IC50 42.67 µM) cell lines.
Formamides are useful starting materials for pharmaceutical syntheses. Although various synthetic methods have been documented in this regard, the use of N-formylcarbazole as a formylation reagent for amines has not yet been reported. We report here the first examples of the use of N-formylcarbazole for the formylation of amines. The characteristic reactivity of N-formylcarbazole enables the selective formylation of sterically less hindered aliphatic primary and secondary amines. In contrast, sterically bulkier amines and weakly nucleophilic amines such as anilines are less reactive under the reaction conditions.
Due to the importance of the RNA chemical modifications, methods for the selective chemical modification at a predetermined site of the internal position of RNA have attracted much attention. We have developed functional artificial nucleic acids that modify a specific site of RNA in a site- and base-selective manner. In addition, the copper-catalyzed azide-alkyne cycloaddition (CuAAC) has been shown to introduce additional molecules on the alkynes attached to the pyridine ring. However, it was found that some azide compounds produced the cycloadduct in lower yields. Therefore, in this study, we synthesized the pyridinyl transfer group with the alkyne attached via a polyethylene glycol (PEG) linker with a different length and optimized its structure for both the transfer and CuAAC reaction. Three new transfer groups were synthesized by introducing an alkyne group at the end of the triethylene (11), tetraethylene (12) or pentaethylen glycol linker (13) at the 5-position of the pyridine ring of (E)-3-iodo-1-(pyridin-2-yl)prop-2-en-1-one. These transfer groups were introduced to the 6-thioguanine base in the oligodeoxynucleotide (ODN) in high yields. The transfer groups 11 and 12 more efficiently underwent the cytosine modification. For the CuAAC reaction, although 7 showed low adduct yields with the anionic azide compound, the new transfer groups, especially 12 and 13, significantly improved the yields. In conclusion, the transfer groups 12 and 13 were determined to be promising compounds for the modification of long RNAs.
Due to
the importance of chemical modification of RNA, methods for chemical modification
at a predetermined site in an internal position of RNA have attracted much
attention. The authors have developed an original method for the base- and
sequence-specific modification by transferring the functional group of the oligonucleotides
to RNA through the formation of hybrid complexes. To achieve further
modification by copper-catalyzed alkyne-azide cycloadditions, the authors
investigated transfer groups with the tri-, tetra- and pentaethylene
glycol-linked alkynes. As a result, the transfer groups with tetra- and
pentaethylene linkers were determined to be promising compounds to internally modify
long RNA.