Why electron density increase on ortho para positon?
I am assuming that you are refering to a benzene ring, with some sort of subsituent group attached?
If this is the case, the electron density of a benzene ring can be altered by attaching different substiuent groups to it. A group can either push electron density into the ring or withdraw it. If electron density is pushed into the ring from the substituent, either along a sigma bond or through the pi system, then the density is concentrated at the orthro and para positions due to the resonance structures formed when attacked by an electrophile at either of these postions.
Very difficult to explain properly without pictures, I am sorry.
Wikipedia has a page, with more detail under the Ortho/para director heading:
Toluene is an aromatic compound, generally it under goes electrophilic substitution reactions i.e. usually one of the hydrogen, is replaced by an electrophile. It increases the electron density at ortho and para position only not at meta. So electrophile attacks at ortho and para position. Ex. Nitration of Toluene
Nitro group (-NO2), having -I and -R effect, is an electron withdrawing and deactivating group. Due to both these effects, it decreases electron density around the -COOH group of substituted(ortho, meta & para) benzoic acids and releases H+ ions, making these acidic. The nitrobenzoic acid which releases H+ group more easily is the most acidic. Due to ortho effect, ortho acids are more acidic than all other substituted acids(even if an electron donating group is…
I think you're asking about ortho-para directors. o,p directors are groups bonded to a benzene ring that direct additional groups in electrophilic aromatic substitution reactions to attach to the ortho and para positions of the benzene ring. Ortho is the position next to the group and para is the position across from the group on the benzene ring. o,p directors are electron donating groups such as methoxy groups. These groups stabilize the positive charge created…
Although chlorine is an electron withdrawing group yet it is ortho - para directing in electrophilic aromatic substitution reactions?
What are the differences between activating and deactivating groups in electrophillic aromatic substitution?
Activating groups donate electron density either through inductive effects or resonance. They are usually ortho and para directed, which means the subsequent groups added will either be in the 2 or 4 position relative to the functional group. It is easy to determine if a functional group is activating if it electronegative molecules are single bonded. Examples: alkyl groups (-CH3), alkoxyl (-OCH3), amino (-NH2), thio (-SH), The exception to the trend that activating groups =…
phenol loses a proton to form phenoxide ion (reason for acidity of phenols). When electron withdrawing groups such as nitro, cyano, carbonyl etc are present on the aromatic ring, the stability of the phenoxide ion increases, the equilibrium shifts to the right. In other words, more protons are formed and the acidity increases. An opposite trend is observed when an electron donating group such as methyl, methoxy etc are present.
Where can you find more information about ortho-cylen if all the websites you see are for low or tricyclen?
The Acetanilide is a benzene with a acetamido group attached to it. The acetamido group is electron donating and therefore it directs other substituents to the ortho and para positions. The acetamido group is also a very large group and the ortho position is right besides the acetamido group. This creates steric hindrance from bromine from getting to the ortho position and therefore only para-bromoacetanilide or 4-bromoacetanilide is created mainly from a bromination of acetanilide.
There are 3 possible places for the nitro group to attach: An ortho, meta, or para position. To understand the stability of the carbocation, we need to look at the resonance structures for a given attack and see what the results are. The first resonance structure of the ortho attack results in a positive charge on the carbon with the hydroxyl group. This happens to be the most stable of the 3 resonance structures for…
You have to determine your electron donating and withdrawing substituent and once that is done identify where the BEST position is for the iodine based on the para, meta and ortho position. Note: Donators (Activators) prefer a para OR ortho addition Withdrawers (Deactivators) prefer the meta position Once that is done you'll find Iodine goes into the meta of the deactivator and para position of the activator POSITION 5!
Why does aniline when subjected to nitration conditions followed by a basic work up form the meta nitroanline and not ortho or para?
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