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b) The groups are directing to different positions, so the more activating group will control the O regiochemistry. The nitrogen attached to the ring is NHCCH₃ activating, whereas the carbonyl group is deactivating. Therefore the substitution occurs ortho and para to the nitrogen group, but not between the two groups as that position is sterically hindered. CCH₃ O CH₃ c) The methoxy group is a stronger activating group than the methyl group, so the substitution occurs ortho to the methoxy group. OCH₃ CH₂CH₃ d) The groups are directing to the same positions, so the substitution occurs ortho to one and para to the other, but not at the position ortho to both because this position is too sterically hindered. CH₂CH₃ O NHCCH₃ e) Both groups are directing to the same positions. NO₂ f) Substitution occurs ortho and para to the hydroxy OH group because it is more activating than chlorine. 249