Glycosylated lanthanide cyclen complexes as luminescent probes for monitoring glycosidase enzyme activity

The development of synthetic chemical probes for the detection of enzymes is extremely important for biological, medicinal, and industrial applications. Here we report the synthesis of an array of novel glycosylated Tb(iii) complexes, their photophysical properties in solution, and their ability to function as luminescent probes for observing glycosidase enzyme activity in real time. Our initial studies into the application of these complexes for the detection of the Concanavalin A (ConA) lectin is also reported, highlighting the broad scope of these novel chemical probes.

Exploring chemoselective S-to-N acyl transfer reactions in synthesis and chemical biology

S -to-N acyl transfer is a high-yielding chemoselective process for amide bond formation. It is widely utilized by chemists for synthetic applications, including peptide and protein synthesis, chemical modification of proteins, protein-protein ligation and the development of probes and molecular machines. Recent advances in our understanding of S -to-N acyl transfer processes in biology and innovations in methodology for thioester formation and desulfurization, together with an extension of the size of cyclic transition states, have expanded the boundaries of this process well beyond peptide ligation. As the field develops, this chemistry will play a central role in our molecular understanding of Biology.

The conversion of thioesters to amides via acyl transfer has become one of the most important synthetic techniques for the chemical synthesis and modification of proteins. This review discusses this S-to-N acyl transfer process, and highlights some of the key applications across chemistry and biology.

Recent advances in the development of synthetic chemical probes for glycosidase enzymes

The emergence of synthetic glycoconjugates as chemical probes for the detection of glycosidase enzymes has resulted in the development of a range of useful chemical tools with applications in glycobiology, biotechnology, medical and industrial research. Critical to the function of these probes is the preparation of substrates containing a glycosidic linkage that when activated by a specific enzyme or group of enzymes, irreversibly releases a reporter molecule that can be detected. Starting from the earliest examples of colourimetric probes, increasingly sensitive and sophisticated substrates have been reported. In this review we present an overview of the recent advances in this field, covering an array of strategies including chromogenic and fluorogenic substrates, lanthanide complexes, gels and nanoparticles. The applications of these substrates for the detection of various glycosidases and the scope and limitations for each approach are discussed.

A copper-catalyzed Petasis reaction for the synthesis of tertiary amines and amino esters

We have developed a copper-catalyzed process for the coupling of aldehydes, amines, and boronic acids. This allows greater reactivity with simple aryl boronic acids and allows coupling reactions to proceed that previously failed. Initial mechanistic studies support a process involving transmetalation from boron to copper.

An assessment of cost, quality and outcomes for five HIV prevention youth peer education programs in Zambia

Youth peer education (YPE) programs are a popular strategy for HIV prevention in sub-Saharan Africa. However, research on the effectiveness of YPE programs is scarce and the wide variation in programs makes it difficult to generalize research findings. Measuring quality and comparing program effectiveness require the use of standardized instruments. In this study, we used standardized evidenced-based instruments to compare program inputs, quality, outputs and outcomes for five YPE programs in Zambia. Clinic surveys were used to measure the following program outcomes: young people's exposure to the YPE programs and referrals of young people to clinics for HIV/sexually transmitted infection (STI) testing and other reproductive health services. The study revealed wide variation in the cost, quality and outcomes of YPE programs. Higher quality programs were associated with greater exposure and more referrals of youth to the clinics. However, one of the two highest quality programs achieved twice as many exposure and referral outcomes at about half the cost per peer educator of the more expensive program. Results indicate that the standardized instruments used in this study are useful for assessing and comparing program attributes among diverse YPE programs.

New synthetic routes to tilorone dihydrochloride and some of its analogues

New synthetic routes to the orally active, interferon-inducing antiviral agent tilorone dihydrochloride, 2,7-bis-[(diethylamino)ethoxy]fluoren-9-one dihydrochloride (1a), were developed. The routes involved the preparation and solvolysis of tetrazonium fluoroborate salts of 2,7-diaminofluoren-9-one. Nonplanar (1b), 9-sulfone (1c), and fluorene (1d) analogues of tilorone dihydrochloride were also prepared. Compounds 1b and 1c were evaluated for interferon induction.