Min Liang Yao

Synthesis, biological evaluation and radiochemical labeling of a dansylhydrazone derivative as a potential imaging agent for apoptosis

To develop a small molecule-based tracer for in vivo apoptosis imaging, dansylhydrazone (DFNSH) was synthesized in 93% yield in less than 30 min. The biological evaluation showed that DFNSH selectively binds to paclitaxel-induced apoptotic cancer cells. The high magnification fluorescent images demonstrate that DFNSH is localized within the cytoplasm of cells that bound Alexa 488 labeled annexin V on the plasma membrane. [(18)F]-DFNSH ([(18)F]-3) was synthesized and isolated in 50-60% radiochemical yields, based on [K/K(222)](18)F, with a synthesis time of 50 min (EOB). The straightforward preparation of fluorine-18 labeled 3 makes it a promising tracer for PET imaging of apoptosis.

Syntheses and characterization of polymer-supported organotrifluoroborates: applications in radioiodination reactions

A novel strategy combining the advantages of polymer-supports and organotrifluoroborate chemistry for radiotracer preparation is reported.

Titanium(IV) halide mediated coupling of alkoxides and alkynes: An efficient and stereoselective route to trisubstituted (E)-alkenyl halides

Alkoxide C-O bond cleavage occurs readily at room temperature in the presence of titanium(IV) halide. Capture of the resultant carbocation by alkynes provides an efficient route to trisubstituted (E)-alkenyl halides with high stereoselectivity.

Boron Trihalide Mediated Alkyne-Aldehyde Coupling Reactions: A Mechanistic Investigation

A boron trihalide mediated alkyne-aldehyde coupling reaction leading to stereodefined 1,3,5-triaryl-1,5-dihalo-1,4-pentadienes is described. The study led to the discovery of a direct substitution of hydroxyl groups by stereodefined alkenyl moieties using alkenylboron dihalides. During the investigation, it was also discovered that, at low temperatures, the reaction of BCl3 with alkynes produces monovinylboron dichloride rather than the reported divinylboron chloride. A modified reaction mechanism for the boron trichloride mediated alkyne-aldehyde coupling reaction is now proposed. The reaction temperature and mode of addition have been found to have dramatic affects on the stereochemistry of the diene products.

Boronated carbohydrate derivatives as potential boron neutron capture therapy reagents

The treatment of cancer remains one of the most challenging problems for humanity. Boron neutron capture therapy is a binary approach for cancer treatment that is particularly attractive in treating high-grade gliomas and metastatic brain tumors. Among the types of boron-containing molecules used as boron neutron capture therapy agents, boronated carbohydrate derivatives have received significant attention because of their preferential uptake by growing tumor cells. This review provides a summary of the recent developments in the chemistry of carborane-containing carbohydrates.

Isotope incorporation using organoboranes

Isotopes have played an important role in chemistry, biology, and medicine. For the last three decades, we have focused on the use of organoboron compounds as precursors to isotopically labeled physiologically active reagents. During that period, we have successfully developed methods for incorporating short- and long-lived isotopes of carbon, nitrogen, oxygen, and the halogens using a variety of reactive organoboron precursors. In addition, labeling strategies employing polymer-supported organoboron derivatives were developed. In this report, we present a short overview focused on the evolution of radiolabeling techniques based on boron chemistry.

Boron trichloride mediated alkyne-aldehyde coupling reactions

The boron trichloride mediated reaction of aryl aldehydes and alkynes can be used to selectively generate either (Z,Z)- or (Z,E)-1,5-dichloro-1,4-dienes as major products, depending on the reaction conditions employed. To investigate the mechanism of this important carbon-carbon bond forming reaction, the boron trichloride mediated reaction of phenylacetylene with p-bromobenzaldehyde was chosen as the model system. Interestingly, when the coupling reactions are carried out below ―60 °C, (E,E)-1,5-dichloro-1,4-dienes are also formed. The ratios of (Z,Z)-, (Z,E)-, and (E,E)-1,5-dichloro-1,4-dienes were correlated to the reaction conditions using gas chromatography-mass spectrometry. The results of the investigation can be used to explain why the ratio of (Z,E)-, (Z,Z)-, and (E,E)-1,5-dichloro-1,4-pentadiene products change very dramatically when changes are made in either the sequence of addition of the reagents or the reaction temperature.