Question

The correct IUPAC name for ${\mathrm{CH}}_2={\mathrm{CHCH}}_2{\mathrm{NHCH}}_3$ is (A) Allymethylamine (B) 2 -amino-4-pentene (C) 4-aminopent-1-ene (D) N-methylprop-2-en-1-amine

Short answer

The correct IUPAC name for the given molecule ${\mathrm{CH}}_2={\mathrm{CHCH}}_2{\mathrm{NHCH}}_3$ is N-methylprop-2-en-1-amine, which corresponds to the option (D).

Step-by-step solution

Longest Carbon Chain

First, identify the longest carbon chain in the molecule. The given molecule has the following longest carbon chain: ${\mathrm{CH}}_2={\mathrm{CHCH}}_2\mathrm{C}$ The carbon chain has 4 carbons, so the parent compound is "but". Since there is a double bond between the first and second carbon atoms, the base name will include "ene".

Identify Functional Groups

Next, identify the functional groups present in the molecule. The functional groups present include an amine group ${\mathrm{NHCH}}_3$.

Assign Locant Numbers

Assign locant numbers to the functional groups according to the IUPAC naming conventions. The amine group is attached to the third carbon atom in the longest chain.

Use Prefixes, Infixes, and Suffixes

Now, we will use prefixes, infixes, and suffixes to name the molecule according to the IUPAC rules. Since there is an amine group attached to the main carbon chain, the suffix "amine" is added to the name. Also, there is a methyl group attached to the nitrogen atom, so we include "N-methyl" as a prefix to specify this additional detail. Moreover, since the double bond is between the first and second carbon atoms, we will use "-1-" to represent the position of the double bond. Combining all these information, the correct IUPAC name for the given molecule is N-methylprop-2-en-1-amine, which corresponds to the option (D).

Key concepts

Understanding Organic Chemistry

Organic chemistry is the branch of chemistry that studies the structure, properties, composition, reactions, and synthesis of organic compounds, which contain carbon atoms. The complexity and diversity of organic molecules arise from the ability of carbon to form stable bonds with itself and other elements, leading to an immense variety of chemical structures. Organic compounds are typically classified based on their functional groups, which are specific groups of atoms within molecules that determine many of their properties and reactions.

Grasping the foundational principles of organic chemistry, such as molecular structure and functional groups, is crucial for beginners as it allows them to understand how organic molecules are named, synthesized, and behave in chemical reactions.

Identifying Functional Groups

Functional groups identification is a vital skill in organic chemistry, as these groups define the characteristics and chemical reactivity of organic molecules. They are specific clusters of atoms that behave in a predictable way, regardless of the molecule they are part of. In the context of the provided problem, the key functional group was the amine group, comprised of a nitrogen atom attached to hydrogen atoms, alkyl or aryl groups.

Functional groups are the backbone for the nomenclature of organic compounds, and recognizing them helps chemists determine the physical properties and predict the types of reactions each compound can undergo. Knowing the priority order of functional groups is also essential for correct IUPAC naming, which underscores the importance of mastering the identification of these groups.

The Art of Alkene Naming

Alkene naming falls within the IUPAC nomenclature system for organic compounds and involves several rules. Alkenes are hydrocarbons with at least one carbon-carbon double bond, represented by the suffix '-ene'. The process of naming an alkene involves several steps, starting with the identification of the longest carbon chain containing the double bond. Numbering of the chain begins from the end nearest to the double bond to give the lowest locant for this feature.

Additional substituents and functional groups are named using prefixes, locants, and infixes before the main alkene name to fully describe the molecule. The key steps are: finding the longest chain, identifying and numbering the double bond, including any substituent groups in alphabetical order, and then combining these elements into the final name. It is this systematic approach that allows the clear communication and standardization of organic compound names across the scientific community.