Total Synthesis of Dragmacidins G and H.

The total synthesis of dragmacidins G and H was achieved for the first time by employing nucleophilic aromatic substitution and site-selective cross-coupling reactions using appropriately functionalized pyrazines as substrates. The evaluation of antibacterial activities of dragmacidin G, dragmacidin H, and synthetic analogues against and the efflux pump-deficient Typhimurium revealed that the presence of a Br group on the indole ring adjacent to the sulfide unit was important for increasing antibacterial activities.

Innovative receiving phase for Chemcatcher® passive sampler for phosphorus in the water environment: Calibration of sampling rate by water temperature and pH.

Passive sampling is a technique for monitoring orthophosphate (PO-P) in the water environment. Compared with traditional grab sampling followed by PO-P quantification, kinetic-type passive samplers such as Chemcatcher® express representative concentrations of PO-P as time-weighted average concentrations (C). They can also potentially evaluate much lower PO-P concentrations, but the available receiving phases of Chemcatcher® used for PO-P were extremely limited.