Sortase-Modified Cholera Toxoids Show Specific Golgi Localization.

Cholera toxoid is an established tool for use in cellular tracing in neuroscience and cell biology. We use a sortase labeling approach to generate site-specific N-terminally modified variants of both the A2-B heterohexamer and B pentamer forms of the toxoid. Both forms of the toxoid are endocytosed by GM1-positive mammalian cells, and while the heterohexameric toxoid was principally localized in the ER, the B pentamer showed an unexpectedly specific localization in the medial/trans-Golgi.

Sustainability Challenges and Opportunities in Oligonucleotide Manufacturing.

With a renewed and growing interest in therapeutic oligonucleotides across the pharmaceutical industry, pressure is increasing on drug developers to take more seriously the sustainability ramifications of this modality. With 12 oligonucleotide drugs reaching the market to date and hundreds more in clinical trials and preclinical development, the current state of the art in oligonucleotide production poses a waste and cost burden to manufacturers. Legacy technologies make use of large volumes of hazardous reagents and solvents, as well as energy-intensive processes in synthesis, purification, and isolation.

Phosphorothioate anti-sense oligonucleotides: the kinetics and mechanism of the sulfurisation of phosphites by phenylacetyl disulfide (PADS).

In the pharmaceutical industry the sulfurisation of nucleotide-phosphites to produce more biologically stable thiophosphates is often achieved using 'aged' solutions of phenylacetyl disulfide (PADS) which consist of a mixture of polysulfides that are more efficient sulfur transfer reagents. However, both 'fresh' and 'aged' solutions of PADS are capable of the sulfurisation of phosphites. The rates of both processes in acetonitrile are first order in sulfurising agent, phosphite and a pyridine base, although with 'aged' PADS the rate becomes independent of base at high concentrations.

Phosphorothioate anti-sense oligonucleotides: the kinetics and mechanism of the generation of the sulfurising agent from phenylacetyl disulfide (PADS).

The synthesis of phosphorothioate oligonucleotides is often accomplished in the pharmaceutical industry by the sulfurisation of the nucleotide-phosphite using phenylacetyl disulfide (PADS) which has an optimal combination of properties. This is best achieved by an initial 'ageing' of PADS for 48 h in acetonitrile with 3-picoline to generate polysulfides. The initial base-catalysed degradation of PADS occurs by an E1cB-type elimination to generate a ketene and acyldisulfide anion.

Discovery of a Selective S1P1 Receptor Agonist Efficacious at Low Oral Dose and Devoid of Effects on Heart Rate.

Gilenya (fingolimod, FTY720) was recently approved by the U.S. FDA for the treatment of patients with remitting relapsing multiple sclerosis (RRMS).

Stereoselective synthesis of cyclohexanones via phase transfer catalyzed double addition of nucleophiles to divinyl ketones.

Functionalized cyclohexanones are formed in excellent yield and diastereoselectivity from a phase transfer catalyzed double addition of active methylene pronucleophiles to nonsymmetrical divinyl ketones.

Stereoselective double Friedel-Crafts alkylation of indoles with divinyl ketones.

A tandem double Friedel-Crafts reaction of indoles and nonsymmetrical divinyl ketones has been achieved. The tandem reaction forms complex [6-5-7]-tricyclic indoles in excellent yields. The reaction is completely regioselective and offers high levels of syn diastereoselectivity.

Asymmetric phase-transfer catalysis utilizing chiral quaternary ammonium salts: asymmetric alkylation of glycine imines.

O-Alkyl N-anthracenylmethyl derivatives of Cinchona alkaloids can function as enantioselective phase-transfer catalysts. By employing these catalysts in the asymmetric alkylation of glycine imines, one can generate a range of alpha-amino acid derivatives with high levels of enantiomeric excess. It is also possible to generate the catalysts in situ from commercially available chiral amines, which offers the opportunity to evaluate libraries of related structures.

Computational screening of combinatorial catalyst libraries.

A catalyst design methodology, utilizing combinatorial synthesis in parallel with chemometric analysis, is presented, which considers the 3D steric and electrostatic properties of substituents about a constant core structure.

Catalysis of the Asymmetric Desymmetrization of Cyclic Anhydrides by Nucleophilic Ring-Opening with Alcohols.

The single symmetry-breaking transformation of a relatively simple meso compound can provide highly expedient access to a wide variety of usefully functionalized chiral building blocks. Recent advances in asymmetric desymmetrization, through the development of tertiary amines as nonenzymatic catalysts for the ring opening of meso cyclic anhydrides with alcohols [for example, see Eq. (1)], are discussed here.