Breaking through the milligram floor: When chemists synthesize compounds, the threshold for success is at least a milligram of product. This has been true for decades—even though biochemical assays have long since descended into microgram territory—and results in part from the constraints of characterization methods. Buitrago Santanilla et al. present an automated dosing and characterization protocol for optimizing chemical reaction conditions on the microgram scale. This allowed them to screen numerous base and ligand combinations for catalytic C-N bond-forming reactions between complex pairs of compounds, in short supply, that resisted standard coupling conditions. Science , this issue p. 49

Applications of aerobic oxidation methods in pharmaceutical manufacturing are limited in part because mixtures of oxygen gas and organic solvents often create the potential for a flammable atmosphere. To address this issue, limiting oxygen concentration (LOC) values, which define the minimum partial pressure of oxygen that supports a combustible mixture, have been measured for nine commonly used organic solvents at elevated temperatures and pressures. The solvents include acetic acid, N-methylpyrrolidone, dimethyl sulfoxide, tert-amyl alcohol, ethyl acetate, 2-methyltetrahydrofuran, methanol, acetonitrile, and toluene. The data obtained from these studies help define safe operating conditions for the use of oxygen with organic solvents.