Substituent Priority Assignment

This manuscript describes the Research Prioritization by Affected Communities (RPAC) protocol and findings from its use with women at risk for preterm birth. Using the protocol, women identified and prioritized their unanswered questions about pregnancy, birth and neonatal care aimed at influencing research priority setting by funders and researchers.

Substituents on the benzene ring that direct an incoming electrophile to undergo substitution at the meta position are called meta directors. All meta directors either have a positive charge on the atom directly bonded to the ring or a partial positive charge. These groups function by withdrawing electrons from the ring through inductive and resonance effects. Consider the carbocation intermediates formed upon the addition of an electrophile on nitrobenzene at the ortho, meta, and para...

In the presence of heat or light, alkanes react with molecular halogens to form alkyl halides by a substitution reaction called radical halogenation. This reaction has three steps: initiation, propagation, and termination, as seen in the radical chlorination of methane to produce methyl chloride. In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...

When more than one substituent is present on the benzene ring, the IUPAC nomenclature depends on the number of substituents present. For disubstituted benzene derivatives, with two groups attached to the benzene ring, three constitutional isomers are possible. For example, consider dimethyl benzene, often called xylene, where the second methyl group can be substituted at the second, third, or fourth carbon. The relative position of the substituents is represented by prefixes ortho, meta, or...

The acidity of carboxylic acids is influenced by the nature of the substituents bounded to the functional group. The acid strength is determined by the stability of the carboxylate anion—the conjugate base formed by dissociating the corresponding carboxylic acid. Suppose the carboxylic acid bears an electron-withdrawing substituent. In that case, it stabilizes the conjugate base through the electron-withdrawing inductive effect, thereby decreasing the electron density on the carboxylate anion...