Will 2c-b form a grignard reagent (specific to the aromatic bromine)? Will dripping an ethereal solution of 2c-b into the grignard addition product of ethyl bromide produce 2c-e?
No and no. The grignard reagent is incompatible with the amine.
Found that grignard reagents react with nitriles, but what about terminal nitrogens saturated with either hydrogen or oxygen? (ie, 2c-b or 4-bromo-2,5-dimethoxy-nitroethane?) SWID is unsure if the double carbon bond in a styrene would have any effect or not.
Grignard reagents can usually not be made from compounds containing any of the following groups: nitriles, acids, carbonyl functions (ketone/aldehyde/ester/amide/anhydride) and any functional group containing -NO2, -OH, -SH, or -NH groups.