Question

Correct option(s) regarding reaction, reactant and product respectively given is : (A) Schmidt reaction Acid Primary amine (B) Hoffmann bromamide Primary acid amide Primary amine (C) Schmidt reaction Ketone Secondary acid amide (D) Beckmann rearrangement Ketoxime Secondary acid amide

Short answer

The correct options are: (B) Hoffmann bromamide Primary acid amide Primary amine (D) Beckmann rearrangement Ketoxime Secondary acid amide

Step-by-step solution

Option A Analysis

Option A mentions the Schmidt reaction with acid and primary amine as reactants and product. The Schmidt reaction occurs between a carboxylic acid and a hydrazoic acid (HN3) to form an amide. Primary amines do not participate in the Schmidt reaction. Thus, option A is incorrect.

Option B Analysis

Option B presents the Hoffmann bromamide reaction involving primary acid amide as reactant and primary amine as the product. The Hoffmann bromamide reaction occurs between primary amides and bromine in the presence of a base to yield primary amines. This option is correct.

Option C Analysis

Option C discusses the Schmidt reaction again, this time with ketone and secondary acid amide as reactants and product. Schmidt reaction of ketones with hydrazoic acid (HN3) forms isocyanates, which can later be hydrolyzed to primary amines. This option does not match the reaction with the correct product, so option C is incorrect.

Option D Analysis

Option D introduces the Beckmann rearrangement reaction involving ketoxime as reactant and secondary acid amide as the product. The Beckmann rearrangement occurs when ketoximes are treated with an acid to form secondary acid amides. Therefore, this option is correct. In conclusion: Solution: The correct options are: (B) Hoffmann bromamide Primary acid amide Primary amine (D) Beckmann rearrangement Ketoxime Secondary acid amide

Key concepts

Schmidt Reaction

The Schmidt Reaction is a chemical reaction that typically involves the conversion of carboxylic acids into amines. It employs hydrazoic acid, represented by the formula HN₃, in an acidic medium. Although one might assume primary amines could be involved as reactants, this is incorrect.

• The reaction transforms either a carboxylic acid or a ketone.
• When carboxylic acids are used, the reaction leads to the formation of amides.
• With ketones, the result is isocyanates, which can further be hydrolyzed to form primary amines.

Understanding this reaction is essential in organic synthesis, especially for producing nitrogen compounds. Remember, the Schmidt Reaction is not directly involving primary amines as reactants.

Hoffmann Bromamide Reaction

The Hoffmann Bromamide Reaction is a notable reaction in organic chemistry where primary amides are converted into primary amines. It's particularly useful for removing the carbonyl group from an amide.

• You begin with a primary amide.
• The reaction requires bromine and a strong base, typically sodium or potassium hydroxide.
• Through a series of steps, including halogenation and rearrangement, the product is a primary amine with one less carbon atom than the original amide.

This reaction is highly valued for its ability to transform compounds without retaining the carbonyl group. It's a classic tool in synthetic organic chemistry.

Beckmann Rearrangement

Beckmann Rearrangement is a remarkable transformation in organic chemistry that involves converting oximes into amides. Specifically, ketoximes rearrange to produce secondary amides when treated under acidic conditions.

• The starting material is a ketoxime, often derived from a ketone.
• An acid catalyst, such as sulfuric acid or PCl₅, is used to promote rearrangement.
• The result is the migration of an alkyl group adjacent to the oxime group, forming a new amide bond.

This rearrangement is crucial for forming complex amide structures and is often utilized in both academic and industrial chemical syntheses.

Reaction Mechanisms

Understanding reaction mechanisms is central to mastering organic chemistry. These mechanisms detail each step of a chemical reaction, illustrating how reactants are converted to products.

• Reaction mechanisms involve understanding the step-by-step transformation of molecules.
• They explain the role of different reagents, catalysts, and conditions needed for the reaction.
• Knowing mechanisms helps predict reaction outcomes and design new synthetic pathways.

Comprehending these mechanisms empowers chemists to effectively manipulate chemical reactions, making the study of organic chemistry both practical and powerful.