Jianghong Rao, Postdoctoral Faculty Sponsor
(1) development of new chemical probes for studying biological problems in human health and disease, (2) method for fast and specific post-synthesis modification of DNA and its further applications for, e.g. aptamer selection and array analysis (3) borononic acid-based lectin mimics (5) drug design, synthesis and biological evaluation
DNA molecules are known to be important materials in sensing, aptamer selection, nanocomputing, and construction of unique architectures. The incorporation of modified nucleobases affords unique DNA properties for applications in areas that would otherwise be difficult or not possible. Earlier, we demonstrated that the boronic acid moiety can be introduced into DNA through polymerase-catalyzed reactions. In order to study whether such incorporation by polymerase is a general phenomenon, we designed and synthesized four boronic acid-modified thymidine triphosphate (TTP) analogues. The synthesis of certain analogues was through the use of a single dialkyne tether for both the Sonogashira coupling with thymidine and the later Cu-mediated [3+2] cycloaddition for linking the boronic acid moiety. This approach is much more efficient than the previously described method, and paves the way for the preparation of a large number of boronic acid-modified TTPs with a diverse set of structural features. All analogues showed very good stability under polymerase chain reaction (PCR) conditions and were recognized as a substrate by DNA polymerase, and thus incorporated into DNA.
View details for DOI 10.1002/asia.201100229
View details for Web of Science ID 000296273900015
View details for PubMedID 21887745
Boronic acids have been widely used in a wide range of organic reactions, in the preparation of sensors for carbohydrates, and as potential pharmaceutical agents. With the growing importance of click reactions, inevitably they are also applied to the synthesis of compounds containing the boronic acid moiety. However, such applications have unique problems. Chief among them is the issue of copper-mediated boronic acid degradation in copper-assisted [2,3]-cycloadditions involving an alkyne and an azido compound as the starting materials. This review summarizes recent developments, analyzes potential issues, and discusses known as well as possible solutions.
View details for DOI 10.3390/molecules15085768
View details for Web of Science ID 000281481100044
View details for PubMedID 20733546
Carbohydrates are known to mediate a large number of biological and pathological events. Small and macromolecules capable of carbohydrate recognition have great potentials as research tools, diagnostics, vectors for targeted delivery of therapeutic and imaging agents, and therapeutic agents. However, this potential is far from being realized. One key issue is the difficulty in the development of "binders" capable of specific recognition of carbohydrates of biological relevance. This review discusses systematically the general approaches that are available in developing carbohydrate sensors and "binders/receptors," and their applications. The focus is on discoveries during the last 5 years.
View details for DOI 10.1002/med.20155
View details for Web of Science ID 000275399200002
View details for PubMedID 19291708
Fluorescent boronic acids are very useful for the design and synthesis of carbohydrate sensors. In an earlier communication, we first described the effort of developing water soluble fluorescent alpha-amidoboronic acids, which change fluorescence upon sugar binding. In this report, we describe a general method of functionalizing such boronic acids and their applications in the preparation of bis-alpha-amidoboronic acids with significantly enhanced binding for oligosaccharides as compared to their monoboronic acid counterparts. The advantages of good water solubility, easy modification to generate diversity, and modularity in synthesis will make alpha-amidoboronic acids very useful building blocks for future synthesis of boronic acid-based fluorescent sensors.
View details for DOI 10.1016/j.bmc.2010.01.017
View details for Web of Science ID 000274425500010
View details for PubMedID 20129789
The boronic acid group is an important recognition moiety for sensor design. Herein, we report a series of isoquinolinylboronic acids that have extraordinarily high affinities for diol-containing compounds at physiological pH. In addition, 5- and 8-isoquinolinylboronic acids also showed fairly high binding affinities towards D-glucose (K(a)=42 and 46 M(-1), respectively). For the first time, weak but encouraging binding of cis-cyclohexanediol was found for these boronic acids. Such binding was coupled with significant fluorescence changes. Furthermore, 4- and 6-isoquinolinylboronic acids also showed the ability to complex methyl α-D-glucopyranose (K(a)=3 and 2 M(-1), respectively).
View details for DOI 10.1002/chem.201000637
View details for Web of Science ID 000285398400031
View details for PubMedID 20938931
Bacterial quorum sensing has received much attention in recent years because of its relevance to pathological events such as biofilm formation. Based on the structures of two lead inhibitors (IC50: 35-55 microM) against autoinducer-2-mediated quorum sensing identified through virtual screening, we synthesized 39 analogues and examined their inhibitory activities. Twelve of these new analogues showed equal or better inhibitory activities than the lead inhibitors. The best compound showed an IC50 value of approximately 6 microM in a whole-cell assay using Vibrio harveyi as the model organism. The structure-activity relationship is discussed herein.
View details for DOI 10.1002/cmdc.200900180
View details for Web of Science ID 000270027800009
View details for PubMedID 19533733
Fluoride has been found to protect boronic acids from copper(i)-mediated decomposition; such findings should be very useful for the preparation of boronic acid-based carbohydrate sensors and boronic acid conjugates using the copper(i)-mediated click reaction.
View details for DOI 10.1039/b909575f
View details for Web of Science ID 000269326900010
View details for PubMedID 19707636
To design and synthesize new arylsubstituted imidazolin-2-one analogues as antitumor compounds.Arylsubstituted imidazolin-2-ones were prepared by condensation the appropriate omega-amino-acetophenone hydrochloride with arylisocyanate in toluene. The target compounds prepared in this study were tested for cytotoxicity against PC-3, A549, HO-8910, Hela, HL60, K562 and HL60R cancer cell lines, and mechanism of one of the products 4y was further evaluated with its mechanium.Thirty-six new compounds were synthesized and confirmed by 1H NMR, MS and elemental analysis. One of the synthesized products, compound 4y, displayed an encouraging selective activity against HL60 cells, and it was partlydue to the cell cycle arrest and cell apoptosis.Compound 4y is worthy to be intensively studied.
View details for PubMedID 16268505