Chapter 19.15, Problem 42ATS

(a)

Interpretation Introduction

Interpretation:

Reaction of o-bromonitrobenzene with sodium hydroxide at elevated temperature forms only one product. For this reaction –

Structure of the product has to be drawn

Concept Introduction:

• Aromatic compounds undergo another type of reactions namely Aromatic nucleophilic substitution reactions designated as ${\text{S}}_{\text{N}}\text{Ar}$.

• A nucleophile, unlike an electrophile is a species that is electron rich and always attracted towards electron deficient site. A nucleophile is mobile unlike electrophile.

• The criteria for aromatic nucleophilic substitution reaction to occur are –

• The aromatic ring must contain a strong electron withdrawing group like nitro group.

• The aromatic ring must contain a leaving group

• The leaving group must be posited either ortho or para position to the strong electron withdrawing group.

• In the mechanism of ${\text{S}}_{\text{N}}\text{Ar}$ reaction the nucleophile attacks the position that is bonded to leaving group and forms a resonance stabilized intermediate called Meisenheimer complex.

• Let the substituent be ‘X’ that then $\text{C-X}$ bond gets broken and  $\text{C-Nu}$ bond is formed. The substituent ‘X’ is termed as ‘Leaving group’. A good leaving is large in size with high electron affinity that they are capable to grabbing the bond pair electron and leaving form the aromatic C atom. Halogens are known to be excellent leaving group.

• The overall reaction can be represented as follows –

                    

(b)

Interpretation Introduction

Interpretation:

Reaction of o-bromonitrobenzene with sodium hydroxide at elevated temperature forms only one product. For this reaction –

Intermediate formed in the reaction has to be identified.

Concept Introduction:

• Aromatic compounds undergo another type of reactions namely Aromatic nucleophilic substitution reactions designated as ${\text{S}}_{\text{N}}\text{Ar}$.

• A nucleophile, unlike an electrophile is a species that is electron rich and always attracted towards electron deficient site. A nucleophile is mobile unlike electrophile.

• The criteria for aromatic nucleophilic substitution reaction to occur are –

• The aromatic ring must contain a strong electron withdrawing group like nitro group.

• The aromatic ring must contain a leaving group

• The leaving group must be posited either ortho or para position to the strong electron withdrawing group.

• In the mechanism of ${\text{S}}_{\text{N}}\text{Ar}$ reaction the nucleophile attacks the position that is bonded to leaving group and forms a resonance stabilized intermediate called Meisenheimer complex.

• Let the substituent be ‘X’ that then $\text{C-X}$ bond gets broken and  $\text{C-Nu}$ bond is formed. The substituent ‘X’ is termed as ‘Leaving group’. A good leaving is large in size with high electron affinity that they are capable to grabbing the bond pair electron and leaving form the aromatic C atom. Halogens are known to be excellent leaving group.

• The overall reaction can be represented as follows –

                    

(c)

Interpretation Introduction

Interpretation:

Reaction of o-bromonitrobenzene with sodium hydroxide at elevated temperature forms only one product. For this reaction –

Feasibility of the reaction if the reactant is m-bromonitrobenzene.

Concept Introduction:

• Aromatic compounds undergo another type of reactions namely Aromatic nucleophilic substitution reactions designated as ${\text{S}}_{\text{N}}\text{Ar}$.

• A nucleophile, unlike an electrophile is a species that is electron rich and always attracted towards electron deficient site. A nucleophile is mobile unlike electrophile.

• The criteria for aromatic nucleophilic substitution reaction to occur are –

• The aromatic ring must contain a strong electron withdrawing group like nitro group.

• The aromatic ring must contain a leaving group

• The leaving group must be posited either ortho or para position to the strong electron withdrawing group.

• In the mechanism of ${\text{S}}_{\text{N}}\text{Ar}$ reaction the nucleophile attacks the position that is bonded to leaving group and forms a resonance stabilized intermediate called Meisenheimer complex.

• Let the substituent be ‘X’ that then $\text{C-X}$ bond gets broken and  $\text{C-Nu}$ bond is formed. The substituent ‘X’ is termed as ‘Leaving group’. A good leaving is large in size with high electron affinity that they are capable to grabbing the bond pair electron and leaving form the aromatic C atom. Halogens are known to be excellent leaving group.

• The overall reaction can be represented as follows –

                    

(d)

Interpretation Introduction

Interpretation:

Reaction of o-bromonitrobenzene with sodium hydroxide at elevated temperature forms only one product. For this reaction –

Feasibility of the reaction if the reactant is p-bromonitrobenzene.

Concept Introduction:

• Aromatic compounds undergo another type of reactions namely Aromatic nucleophilic substitution reactions designated as ${\text{S}}_{\text{N}}\text{Ar}$.

• A nucleophile, unlike an electrophile is a species that is electron rich and always attracted towards electron deficient site. A nucleophile is mobile unlike electrophile.

• The criteria for aromatic nucleophilic substitution reaction to occur are –

• The aromatic ring must contain a strong electron withdrawing group like nitro group.

• The aromatic ring must contain a leaving group

• The leaving group must be posited either ortho or para position to the strong electron withdrawing group.

• In the mechanism of ${\text{S}}_{\text{N}}\text{Ar}$ reaction the nucleophile attacks the position that is bonded to leaving group and forms a resonance stabilized intermediate called Meisenheimer complex.

• Let the substituent be ‘X’ that then $\text{C-X}$ bond gets broken and  $\text{C-Nu}$ bond is formed. The substituent ‘X’ is termed as ‘Leaving group’. A good leaving is large in size with high electron affinity that they are capable to grabbing the bond pair electron and leaving form the aromatic C atom. Halogens are known to be excellent leaving group.

• The overall reaction can be represented as follows –