Important Organic Chemistry & Organic Formulas for JEE and NEET

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1. (Alkane) 

Wurtz reaction : e.g., R¹ X + R²X + 2 Na → R¹- R² + 2NaX

Decarboxylation : 
General reaction 
Mechanism 
The thermal decarboxylation of free acids may be :

(2. Alkyl halide)

Nucleophilic substitution Reaction (S_N1, S_N2)
S_N1 reaction :

Mechanism

e.g.

S_N2 reaction : Alkylhalide are hydrolysed to alcohol very solwly by water, but rapidly by silver oxide suspended in boiling water.
RX + KOH → ROH + KX
Mechanism

Williamson’s synthesis: It is the reaction in which sodium or potassium alkoxide is heated with an alkyl halide (S_N2).

This method is particularly useful for preparing mixed ethers.

3. Grignard Reagents

The majority of Grignard reactions fall in to two groups
(i) Addition of the Grignard reagent to a compound containing a multiple - bond group e.g.

(ii) Double decompsition with compounds containing an active hydrogen atom or a reactive halogen atom.

Important chemical synthesis by Grignard reagent
1. Hydrocarbons:

2. Alcohols:
(a) Primary alcohols
(b) Secondary alcohols
(c) Tertiary alcohols:

3. Ethers: R¹OCH₂CI + R²MgX → R¹OCH₂R² + MgXCI

4. Aldehydes:

5. Ketones:

6. Acids:

7. Esters:

8. Alkyl Cyanides:
RMgX + (CN)₂ → RCN + Mg(CN)x

9. Primary amines :

4. Alkene & Alkyne

Electrophilic addition reactions :
Mechanism
Step 1 : Attack of the electrophile on k bond forms a carbocation.

Step 2 : Attack by a nucleophile gives the product of addition.

e.g. (a) Addition of water

(b) Addition of hydrogen halides (where HX = HCI, HBr, HI)

5. Aromatic compounds

Electrophilic aromatic substitution :
(a) Bromination of Benzene : Bromination follows the general mechanism for electrophilic aromatic substitution. Bromine itself is not sufficiently electrophilic to react with benzene, but a strong Lewis acid such as FeBr₃ catalyzes the reaction.
Step 1 : Formation of a stronger electrophile.

Step 2 : Electrophilic attack and formation of the sigma complex.

Step : 2 Loss of a proton gives the products.

(b) Nitration

(c) Sulphonation: The electrophilic reagent, SO₃, attacks the benzene ring to form the intermediate carbocation.

(d) Friedel Craft reaction : Alkylation mechanism
(i)
(ii)
(iii)
Acylation mechanism
Acylation of benzene may be brought about with acid chlorides or anhydrides in presence of Lewis acids.
Step 1 : Formation of an acylium ion.

Step 2 : electrophilic attack.

Step 3 : Loss of a proton. Complexation of the product.

e.g.
Note : Friedal - Crafts acylations are generally free from rearrangements and multiple substitution. They do not go on strongly deactivated rings.
e.g.

Chemical Reactions of Benzene :

Nucleophilic Aromatic Substitution : The reaction is second-order in which nucleophilic sbustitution occurs on benzene ring. It is generally accepted that the reaction proceeds via an intermediate o-complex, the benzenonium carbanion (or the pentadienyl anion), e.g.,

6. Chemical Reactions of Phenol

Reimer-Tiemann reaction : The reaction is conversion of phenol to salicylaldehyde. The mechanism of the Reimer-Tiemann reaction is believed to involve the formation of dichloromethylene.

Kolbe Reaction : It is the industrial method of preparation of salicylic acid from phenol.
General reaction: 
Mechanism 

7. Chemical reactions of aniline

Sandmyer’s Reaction : When a diazonium salt solution is run into a solution of cuprous halide dissolved in the corresponding halogen acid, the diazo-group is replaced by a halogen atom.
m - Chloronitrobenzene

p-Bromotoluene

Chemical Reactions of Aniline :

8. Aldehyde & ketone

Aldol condensation: Carbonyl compounds having acidic α - H shows this reaction in presence of dil. NaOH or dil. acid.

Crossed aldol condensation

Cannizzaro reaction :
Carbonyl compounds not having α-H shows following disproportion reaction

Crossed Cannizzaro reaction:

Formation of hydrzones and azines

Amides formation:

Carbyl amine reaction

Perkin reaction :
When benzaldehyde (or any other aromatic aldehyde) is heated with the anhydride of an aliphatic acid (containing two α-hydrogen atoms) in the presence of its sodium salt, condensation takes place to form a β-arylacrylic acid ; e.g., with acetic an hydride and sodium acetate, cinnamic acid is formed.

9. Ester formation

General reaction

Hydrolysis of ester

10. Carboxylic Acids

Chemical Reactions of acids