Summary Activating, Ortho, Para-Directors

In summary, as shown in Table 16.1, the halogens and all the activating substituents are ortho-para directors. All substituents more deactivating than the halogens are meta directors. Put another way, all substituents that donate electrons into the ring inductively or by resonance are ortho-para directors, and all substituents that cannot donate electrons into the ring inductively or by resonance are meta directors. 

In summary, we have seen that both a methyl group and a methoxy group activate the ring and are ortho-para directors. This is in fact a general rule that will be used extensively throughout the rest of this chapter All activators are ortho-para directors. 

Both activators and deactivators can be classified as strong, moderate, and weak. Each of these categories is described below, followed by a summary chart of all six categories. As discussed in the preceding sections, the activators are ortho-para directors, while the deactivators, except for the halogens, are meta directors. 

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