An efficient regioconvergent synthesis of 3-aza-obeticholic acid.

Bile acids (BAs) are steroidal molecules that play important roles in nutrient absorption, distribution, and excretion. They also act on specific receptors implicated in various metabolic and inflammatory diseases demonstrating their importance as potential drug candidates. Accordingly, there has been a concerted effort to develop new BA derivatives to probe structure-activity relationships with the goal of discovering BA analogues with enhanced pharmacological properties.

Site-Selective Photobromination of -Acetylated Carbohydrates in Benzotrifluoride.

Ferrier photobromination enables direct synthetic access to valuable 5--bromosugars but has limitations that restrict its broader use. The reaction is typically conducted in CCl heated at reflux with irradiation by broad spectrum, energy-inefficient heat lamps. Herein, we demonstrate that the reaction proceeds rapidly and efficiently with PhCF as a safe and environmentally benign alternative to CCl at mild temperatures (≤40 °C) inside a compact photoreactor fitted with purple light-emitting diodes (LEDs).

Novel 4-O-β-d-xylopyranosyl-3,6-anhydro-l-galactopyranosyl disaccharide units in a polysaccharide from the red alga Pyrophyllon subtumens.

Thalli of the endemic epiphytic New Zealand red seaweed Pyrophyllon subtumens are known to contain a high level of xylose and a notable amount of arabinose but the extracted polysaccharide has not been characterised. The linkage/substitution of individual sugars within the water-soluble polysaccharide extract and various derivatives were determined by chemical and spectroscopic methods. No 3-linked sugars nor any d-galactose were found, which excluded agar-, carrageenan- or mixed 3-linked/4-linked β-d-xylan-type polysaccharides found in many other red macroalgae.

The international scandal of defective asparaginase: A blight on children with cancer.

Acute lymphoblastic leukemia is the commonest form of cancer in children and adolescents worldwide, and asparaginase is an essential component of successful chemotherapy for this disease associated with long-term survival rates often exceeding 90% in high-income countries. Demonstrably defective preparations of asparaginase, distributed from China and India, increase the burden of morbidity and mortality, reducing attainable survival rates. This adverse outcome is enabled by inadequate regulation and oversight, especially in resource-poor settings in low- and middle-income countries where the great majority of children and adolescents with cancer live.

The discovery of 12β-methyl-17-epi-18-nor-bile acids as potent and selective TGR5 agonists.

Recent discoveries have demonstrated that the physiological function of bile acids extends to the regulation of diverse signaling processes through interactions with nuclear and G protein-coupled receptors, most notably the Farnesoid-X nuclear receptor (FXR) and the G protein-coupled bile acid receptor 1 (GPBAR1, also known as TGR5). Targeting such signaling pathways pharmacologically, i.e.