Electrophilic Aromatic Substitution (EAS)

electron donating groups (EDG)

- groups that have a lone pair to donate to increase electron density of a pi system (-NR2, -NHR, -NH2, -OR, -OH)
- Ring activating, more nucleophilic

electron withdrawing groups (EWG)

- groups that remove electron density from a pi system (-CF3, -CN, -SO3H, -NH3(+), NO2, -COOH)
- Ring deactivating, less nucleophilic

electron donating groups (EDG)

- groups that have a lone pair to donate to increase electron density of a pi system (-NR2, -NHR, -NH2, -OR, -OH)
- Ring activating, more nucleophilic

electron withdrawing groups (EWG)

- groups that remove electron density from a pi system (-CF3, -CN, -SO3H, -NH3(+), NO2, -COOH)
- Ring deactivating, less nucleophilic

sodium iodide

serves as the source of iodide ions in the solution

Solution cooling

slows the reaction rate to avoid an unwanted secondary reactions

hypochlorite solution

oxidizing agent which produces iodide ions in the solution

iodide ions

electrophile that reacts with salicylamide to produce the EAS product

sodium thiosulfate

reacts with leftover, unreacted iodine in the solution

HCl

acidifies the mixture to precipitate out the product

EAS steps

1. the aromatic ring acts as a nucleophile and attacks an electrophile
2. the aromatic ring is regenerated through the loss of a proton

EAS

a common reaction of benzene and its derivatives

oxidizing agents purpose

generate the electrophile

iodide and nitric acid are strong....

oxidizers and react unfavorably with combustible material