Page 175 - Pharm.Org.Chem-I 02-06-05-101

II- Deactivating m-orienting groups

1- Strongly deactivating m-orienting groups:
e.g. NO2, +NR3, CF3, CCl3
These groups exert –R and strong –I effects
2- Moderately deactivating m-orienting groups
e.g. CN, SO3H, COOH, COOR, CHO, COR
These groups exert –R and moderate –I effects

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Why NO2 and COR groups are m- orienting ?

Both of them exhibit –R effect generating
a positive charge on o- and p- positions

So, they are m- orienting

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