Organic help

[CJ122638]

Does anyone have a mnemonic or some other trick to easily remember which groups are O/P directing and which are M?

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[asckwan]

http://www.geocities.com/CollegePark/union/5092/mnemMCAT.html

Here's a website with loads of mnemonics. There is one for O/P groups, it's AHA AHA P, just take a look there!

 

[RozhonDDS]

R groups, oxygen bonded to benzene carbon, nh2, carbonyl groups bonded with either an N or O to the benzene and most halogens=ortho/para

Carbonyl groups with the C bonded to the benzene, no2, no3, nitrile, nh3 and some other stuff=meta

 

[CJ122638]

Thanks so much!

 

[SgtSadhu]

Thanks so much!

I know this isnt the best way to explain it, but the way i remember it is

if there is an O or any other electronegative group first attached to it, it will be electron donating and ortho and para directing (benzene-OCH3)

*Note: if the atom attached to the one directly on the ring is more electronegative, it will be deactivating ( benzene- N02)

If there is a halogen, its ortho and para deactivating (Benzene-Cl)

if there is an atom, like a C, and an electronegative atom is attached to that, it will be meta deactivating (beneze-COOh)