Question

Write condensed structures of the following compounds: (a) butan-2,3-dione (b) butanedicarboxylic acid (c) 2 -aminopropanal (d) cyclohexyl 2 -methylpropanoate

Short answer

Condensed structures: (a) CH3-CO-CO-CH3, (b) HOOC-CH2-CH2-COOH, (c) CH3-CH(NH2)-CHO, (d) C6H11O2C(CH3)2

Step-by-step solution

Identify the Main Carbon Chain for butan-2,3-dione

Butan-2,3-dione is a four-carbon compound with two ketone groups. The main carbon chain is butane, and the ketone groups are located at the second and third carbon atoms.

Draw the Condensed Structure for butan-2,3-dione

The condensed structure for butan-2,3-dione is CH3-CO-CO-CH3. Each 'CO' represents a ketone group attached to the main carbon chain.

Identify the Main Carbon Chain for butanedicarboxylic acid

Butanedicarboxylic acid is a four-carbon compound with a carboxylic acid group at each end of the carbon chain.

Draw the Condensed Structure for butanedicarboxylic acid

The condensed structure for butanedicarboxylic acid is HOOC-CH2-CH2-COOH. Each 'COOH' represents a carboxylic acid group attached at the ends of the butane chain.

Identify the Main Carbon Chain for 2-aminopropanal

2-aminopropanal is a three-carbon aldehyde with an amino group (NH2) on the second carbon.

Draw the Condensed Structure for 2-aminopropanal

The condensed structure for 2-aminopropanal is CH3-CH(NH2)-CHO, where 'CHO' represents the aldehyde group at the end of the chain.

Identify the Esters Functional Group and Carbon Chains for cyclohexyl 2-methylpropanoate

Cyclohexyl 2-methylpropanoate is an ester formed from cyclohexanol and 2-methylpropanoic acid.

Draw the Condensed Structure for cyclohexyl 2-methylpropanoate

The condensed structure for cyclohexyl 2-methylpropanoate is C6H11O2C(CH3)2. 'C6H11' represents the cyclohexyl group, 'O2C' is the ester linkage, and '(CH3)2' shows the two methyl groups on the main carbon adjacent to the ester linkage in 2-methylpropanoate.

Key concepts

Butan-2,3-dione Structure

Butan-2,3-dione, sometimes also referred to as biacetyl, is an interesting compound in organic chemistry, particularly known for its role in the flavor of butter. Its structure is based on a four-carbon backbone of butane, where two carbonyl groups (C=O) are attached at the second and third carbon atoms. This means it has a double ketone functionality. When drawing the condensed structure, which is written as CH3-CO-CO-CH3, each 'CO' segment signifies a ketone group. Here's why it's key to indicate the position of the ketone groups: they significantly affect the reactivity and properties of the molecule.

Understanding how to identify and locate functional groups, such as ketones, in a carbon chain is crucial for effectively drawing and interpreting organic molecules.

Butanedicarboxylic Acid Structure

Butanedicarboxylic acid is the name given to a molecule with a four-carbon chain terminated on both ends by carboxylic acid groups. These -COOH groups are highly polar and reactive, making them important in the creation of polyester materials and as an acid in various reactions. Its condensed formula is HOOC-CH2-CH2-COOH. The presence of two carboxyl groups, being at opposite ends of the chain, allows it to act as a dibasic acid in chemistry, meaning it can donate two protons (H+ ions) in reactions. This duality can be harnessed in the formation of complex molecules and polymeric systems, showcasing the significance of understanding a compound's structure and its implications on its chemical behavior.

2-Aminopropanal Structure

2-Aminopropanal falls under the category of alpha-amino aldehydes, compounds that feature both an aldehyde group and an amino group. The structure of 2-aminopropanal is represented by CH3-CH(NH2)-CHO, where 'CHO' denotes the aldehyde and 'NH2' the amino group. The position of these groups on the main chain is critical because they influence the molecule's reactivity, and the '2-' prefix indicates that the substituents are on the second carbon of the propanal chain.

The combination of an aldehyde and an amino group in one molecule can lead to intramolecular reactions, making this compound an essential intermediate in organic synthesis and a focus point for students to understand the intricacies of molecule interactions.

Ester Functional Group

Esters are a pivotal part of organic chemistry, often characterized by their sweet or fruity odors. They contain a functional group with the general formula RCOOR', where R and R' are hydrocarbon chains. The 'O2C' portion in the condensed structure C6H11O2C(CH3)2 represents this functional group, bridging a bond between the oxygen (O) and the carbonyl carbon (C). Esters are formed through a reaction between carboxylic acids and alcohols, known as esterification. The cyclohexyl 2-methylpropanoate example includes a cyclohexyl group (C6H11) and a methyl group (CH3), showing the diversity of ester compounds possible. Grasping how esters are formed and their distinctive group helps students predict the outcome of reactions and the properties of these compounds.

Drawing Organic Molecules

Drawing organic molecules allows chemists and students alike to visualize the structure and understand the potential reactions and properties of a compound. One must be adept at recognizing the main carbon chain, identifying and appropriately placing functional groups, and depicting the connectivity between atoms. This skill is foundational in organic chemistry and is further emphasized through exercises like drawing butan-2,3-dione and butanedicarboxylic acid.

Utilizing condensed structural formulas is a streamlined way to represent molecules concisely, showing the connection between atoms without the need for drawing all single bonds explicitly. It's a balance between providing enough information and maintaining simplicity. When drawing more complex molecules like esters, the ability to break down the molecule into recognizable components becomes invaluable for understanding and applying the principles of organic chemistry.