Illustrated Glossary of Organic Chemistry

Ortho/para director: In electrophilic aromatic substitution, a substituent that favors electrophilic attack ortho or para to the substituent. Most ortho/para directors are also activators, except for the halogens, which are deactivators.

aq. HONO2

aq. H2SO4


Nitration of bromobenzene gives a mixture of ortho-bromonitrobenzene and para-bromonitrobenzene as the major products because the bromine substituent is an ortho/para director.

Bromination of nitrobenzene gives meta-bromonitrobenzene as the major product because the nitro group is a meta director.