Problem 92 - A Complete Resource Book in Chemistry for JEE Main

Question

The product \((\mathrm{Y})\) is O=C1CCCC(NO)C1 (a) O=C1CCCCN1 (b) O=C1CCCCC1 (c) O=C1CCCCO1 (d) O=[N+]([O-])C1CCCCC1

Step-by-Step Solution

Answer

Option (b) O=C1CCCCC1 matches the given product.

Step 1: Analyze the Given Product

The given product has the SMILES notation "O=C1CCCC(NO)C1", which indicates a six-membered ring with a carbonyl group (O=C) at the start, followed by four carbons (CCCC), then a nitrogen oxide (NO), and the ring closure back to the initial carbon (C1). This describes a lactam with a nitrogen group as a substituent.

Step 2: Identify the Compounds in Options

Analyze the SMILES structures of the options: (a) "O=C1CCCCN1" is a five-membered ring with a nitrogen in the ring, (b) "O=C1CCCCC1" is cyclohexanone, a six-membered ring with a single carbonyl, (c) "O=C1CCCCO1" is a five-membered ring meant to be tetrahydrofuranone but with a wrongly positioned carbonyl, and (d) "O=[N+]([O-])C1CCCCC1" represents nitrocyclohexane.

Step 3: Compare Structures to Identify the Match

Compare each option's structure with the product structure. Option (b) "O=C1CCCCC1" matches exactly with the given SMILES string, and the shape and position of atoms in a six-membered ring are identical to that described in the product.

Key Concepts

SMILES notation

SMILES notation is a powerful tool for representing chemical structures in a simple textual format. It stands for Simplified Molecular Input Line Entry System, and it helps chemists convey detailed molecular arrangements with ease.
Through a sequence of letters and symbols, SMILES captures the essence of molecules, including atom types, bonds, and connectivity. For example, in the SMILES string "O=C1CCCC(NO)C1," the structure of a molecule is outlined as follows:

• "O=C" indicates a carbonyl group
• "1" signifies the start of a ring structure
• "CCCC" lists four consecutive carbon atoms
• "(NO)" highlights a nitrogen oxide group attached to the fourth carbon atom, outside of the ring sequence

This concise string provides a clear description, allowing for the quick sharing and analysis of complex chemical information across various platforms.

Lactam structure

Lactams are intriguing types of chemical compounds that are cyclic amides. They are formed when an amide group (-CONH-) is incorporated into a ring structure.
Typically, lactams can vary greatly in size and are often named based on the size of the ring they contain. For instance, a four-membered lactam is known as a β-lactam, while a five-membered one is a γ-lactam.
In the exercise provided, the molecule "O=C1CCCC(NO)C1" incorporates a lactam ring. Here's what it consists of:

• A six-membered ring, making it a δ-lactam
• The carbonyl group (C=O) adds to the amide property of the lactam
• An additional nitrogen group (NO) is present as a substituent attached to one of the carbons in the ring

Understanding lactam structures is essential in organic chemistry as they form the core of many natural products and synthetic pharmaceuticals.

Cyclohexanone

Cyclohexanone is a fundamental building block in organic chemistry, known for its stable six-carbon cyclic structure. It is essentially a ketone with a carbonyl group attached to a cyclohexane ring, providing a key functional unit in various chemical reactions.
The SMILES notation for cyclohexanone is "O=C1CCCCC1," indicating:

• An oxygen double-bonded to a carbon atom, which is part of the ring
• A continues chain of six carbon atoms, forming a perfect cyclohexane ring

Its simple yet significant structure makes cyclohexanone crucial for synthetic chemistry, where it is often used as an intermediate to produce other chemical products. It serves as a starting point for many industrial applications, including the production of nylon and other plastics.

Nitrocyclohexane

Nitrocyclohexane is a notable example of a nitro compound, characterized by the presence of a nitro group (-NO₂) bonded to the cyclohexane ring. This structure imparts unique chemical properties, making it useful in various chemical applications.
In SMILES notation, nitrocyclohexane is expressed as "O=[N+]([O-])C1CCCCC1." This encoding highlights:

• The nitro group, with a positively charged nitrogen (5;[N+]4;)
• Six carbon atoms forming the cyclic base

The nitro group's electron-withdrawing nature influences the reactivity of the compound, making nitrocyclohexane a valuable substance in the synthesis of other compounds, including explosives and pharmaceuticals.