Interpretation:
Reason for the preferential of nitration of pyridine at 3rd position has to be given and also resonance contributors for the intermediate formed by attack of
Explanation of Solution
Pyridine is a base, so in the presence of acid it will be protonated. For nitration at the 3rd position, the additional positive charge is delocalized on three carbon atoms of the pyridine ring. In this case, none of the resonance structures has a +2 charge on the same atom.
For nitration at the 2nd position or 4th position, the additional positive charge on the cation intermediate is also delocalized on three atoms of the pyridine ring, but one of the resonance structure has a +2 charge on nitrogen atom. This situation is less stable than that happens for nitration at the 3rd position.
Want to see more full solutions like this?
Chapter 22 Solutions
ORGANIC CHEMISTRY-OWL V2 ACCESS
- Propanal and propanone react in a similar way with acidified aqueous potassium cyanide, KCN. For this reaction to occur reasonably quickly, the pH of the solution should be approximately 4. Draw a diagram to show the mechanism of the reaction of either propanal or propanone with acidified potassium cyanide.arrow_forwardThe hydrocarbon fluorene was treated with potassium t-butoxide in an acid-base reaction, giving the fluorenide anion and t-butyl alcohol. (a) Which way does the equilibrium lie, and by how much? b) What is the proportion of the fluorenide anion to fluorene? (c) Why is fluorene so highly acidic, considering the pKa of an average alkane is above 50?arrow_forwardTreatment of indene with NaNH2 forms its conjugate base in a Brønsted–Lowry acid–base reaction. Draw all reasonable resonance structures forindene's conjugate base, and explain why the pKa of indene is lower thanthe pKa of most hydrocarbons.arrow_forward
- (a) Account for the following :(i) Propanal is more reactive than propanone towards nucleophilic reagents.(ii) Electrophilic substitution in benzoic acid takes place at meta position.(iii) Carboxylic acids do not give characteristic reactions of carbonyl group.(b) Give simple chemical test to distinguish between the following pairs of compounds:(i) Acetophenone and benzaldehyde(ii) Benzoic acid and ethylbenzoate.arrow_forward4) Aromatic compounds are among the most abundant and versatile in nature. From a synthetic point of view, these compounds, despite their stabilities, are quite useful and can undergo reactions under special conditions and by specific mechanisms, such as the Electrophilic Aromatic Substitution (SAE) and the Nucleophilic Aromatic Substitution (SNAr). Based on this, please answer the following items: (b) How would you prepare the following compounds starting from benzene? Explain the second in a different wayarrow_forward(a) Arrange the following compounds in an increasing order of their indicated property :(i) Benzoic acid, 4-Nitrobenzoic acid, 3,4-Dinitrobenzoic acid, 4-Methoxybenzoic acid (acid strength)(ii) CH3CH2CH (Br) COOH, CH3CH (Br) CH2COOH,(CH3)2CHCOOH, CH3CH2CH2COOH (acid strength)(b) How would you bring about the following conversions :(i) Propanone to Propene (ii) Benzoic acid to Benzaldehyde(iii) Bromobenzene to 1-phenylethanolarrow_forward
- The following substances can be prepared by a nucleophilic addition reaction between an aldehyde or ketoneand a nucleophile. Identify the reactants from which they were prepared. If the substance is an acetal, identifythe carbonyl compound and the alcohol; if it is an imine or enamine, identify the carbonyl compound and theamine. You do not have to consider stereochemistry. In cases where there is more than one answer, just giveone. Use Grignard reagents when an organometallic reagent is required. Draw the Grignard reagent as acovalent magnesium bromide.arrow_forward(a) Although phenoxide ion has more number of resonating structures than carboxylate ion, carboxylic acid is a stronger acid than phenol. Give two reasons.(b) How will you bring about the following converstions?(i) Propanone to propane (ii) Benzoyl chloride to benzaldehyde(iii) Ethanal to but-2-enalarrow_forwardThe ethylation of benzene is an electrophilic substitution reaction. Identify the electrophile in the reaction. Write the equation including reagents and conditions for the ethylation of benzene to produce ethylbenzene. Hence outline the mechanism for the reaction.arrow_forward
- Which of the following reactions will synthesize phenol from benzene? 1) HNO3 + H2SO4; 2) Fe, HCl; 3) NaNO2, HCl, 0-10 oC; 4) warm H2SO4 and H2O 1) HNO3 + H2SO4; 2) Fe, HCl; 3) NaNO2, HCl, 0-10 oC; 4) CuCN; 5) dilute acid and heat 1) Acetyl chloride & AlCl3; 2) bleach 1) Ph-N2+ + KI; 2) BrMgCH=CH2 in ether, followed by H3O+; 3) warm, conc'd KMnO4 1) Cl-CH(CH3)-CH2CH2CH3 + FeBr3; 2) hot, conc'd KMnO4arrow_forwardPlease don't provide handwriting solution Which of the following compounds can undergo nucleophilic aromatic substitution reactions?arrow_forwardThe base-promoted rearrangement of an -haloketone to a carboxylic acid, known as the Favorskii rearrangement, is illustrated by the conversion of 2-chlorocyclohexanone to cyclopentanecarboxylic acid. It is proposed that NaOH first converts the a-haloketone to the substituted cyclopropanone shown in brackets and then to the sodium salt of cyclopentanecarboxylic acid. (a) Propose a mechanism for base-promoted conversion of 2-chlorocyclohexanone to the proposed intermediate. (b) Propose a mechanism for base-promoted conversion of the proposed intermediate to sodium cyclopentanecarboxylate.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning