Naming Other Substituents - Online Tutor, Practice Problems & Exam Prep

Alkyl halides are organic compounds where a halogen acts as a substituent on an alkyl group, with fluorine, chlorine, bromine, and iodine being named fluoro, chloro, bromo, and iodo, respectively. Their position on the parent chain, which could vary in size and structure, must be specified in the compound's name. Additionally, a phenyl group represents a benzene ring (

$C_6{H}_5$

) attached as a substituent to a larger alkane, alkene, or alkyne chain. The phenyl group's naming involves stating its position followed by the name of the parent chain. Understanding the nomenclature of these substituents is crucial for identifying the structure and composition of organic compounds.

Alkyl Halides

So remember that an alkyl halide is just an alkyl group connected to a halogen. Here we're going to say that halogens attached to a carbon chain are named as substituents. Fluorine as a substituent is called fluoro, Chlorine is called chloro, Bromine is called bromo, iodine is called iodo.

In terms of our naming convention, they're acting as substituents. So we'd have to give their numerical location in terms of our parent chain, they are substituents with these names and then we have to worry about what is the parent chain, is it a six member chain, is it cyclic, et cetera.

So just remember, when it comes to naming organic compounds, these halogens serve as substituents, and as substituents, they're given these new names.

Naming Other Substituents Example

So here it says determine systematic name of the following alkane. Our job is first to find the longest carbon chain which represents our parent chain. We're utilizing steps one to six. Remember, we're utilizing the rules that we learn in terms of naming out canes with substituents. You have to watch those videos, make sure you go back and take a look at those six steps.

So here 1²3-4⁵6-7⁸9⁹ seems to be the longest chain that we can have in terms of this alkane. So that is our parent chain. So we'll highlight it for ourselves. Now remember, we numbered from the end closest to a substituent. Here we have a three carbon substituent, A1 carbon substituent and bromine 1²3⁴. To get to this three carbon substituent or 1²3. To get to the bromine substituent, we numbered from the end closest to a substituent, so we're going to number it from the right side.

O 1²3⁴5⁶7⁸9 9 carbons mean that our alkane is no name. Now our substituents 3 carbon substituent with the bond on the middle carbon means that this is isopropyl. One carbon substituent would be methyl and then bromine is bromo. Remember we basically name we number these for their location and we write them alphabetically. B comes before I, I comes before M.

So we start out with three dash bromo, Dash isopropyl is on 6/6 isopropyl and then methyl is on 5/5 methyl. No name. So this would be the name of this particular alkane compound. Here we have the introduction of our halogen bromine group, which is listed as bromo.

Name the following compound.

• A. 3-fluoro-1-ethylpentane
• B. 3-fluoro-1-ethylcyclopentane
• C. 1-ethyl-3-fluorocyclopentane
• D. 1-ethyl-4-fluorocyclpentane

Phenyl Group

In this video, we're going to talk about the fennel group. Now a fennel group is just basically a benzene ring as a substituent on a parent chain. Now here the parent chain can be an alkane, an alkene, an alkyne, as long as it's longer than six carbons. Remember, the formula for benzene is C6H6, but since it's acting as a substituent, we're going to deduct away a hydrogen O.

Here it becomes C6H5 connected to something else, a longer chain that's an alkane, alkene, or an alkyne. Now this is its condensed formula. If we wanted to look at its skeletal formula, remember benzene looks like this. It's a six-membered ring with alternating double and single bonds. Five of the carbons have a hydrogen, the 6th one. Remember we took away its hydrogen so it can serve as a substituent or branch group.

Connect is something larger than itself because it is a substituent. The naming convention is the location of the phenyl group and then the parent chain name. So keep this in mind. Benzene. When it becomes a substituent, we call it fennel.

Naming Other Substituents Example

So here we need to determine a systematic name of the following alkane. Here our carbon chain is this portion, here because it's composed of 12345678 carbons. Remember as long as our carbon chain has more than six carbons it becomes apparent chain and benzene becomes a substituent and then besides that benzene we have these two carbon substituents which are methyl groups.

Now remember we number from the end closest to a substituent. We numbered this end as one because on carbon number one we immediately have a substituent in the form of benzene. So 12345678 and eight carbon chain is octane. Benzene as a substituent is fennel, and then we have methyl groups on carbon 5.

Now we name substituents alphabetically. M comes before P, so those two methyl groups are on five. So we have to list 5 twice because you have. If you just said 5 dimethyl, all I would know is that one of the methyl groups is on carbon 5, but where is the other one? So we have to say 5-5 to say that both of them are on that carbon 5.

S 55. There's two identical substituents, so use the numerical prefix die dimethyl 1 phenyl octane. So this will be the name of my alkane compound.

Draw a structure for the following alkane: 3-tert-butyl-1-phenylheptane.

• A.
• B.
• C.
• D.

Here’s what students ask on this topic:

What is the process of naming alkyl halides?

The process of naming alkyl halides, which are compounds consisting of an alkane with one or more halogen atoms (fluorine, chlorine, bromine, or iodine) replacing a hydrogen atom, follows the rules of the IUPAC (International Union of Pure and Applied Chemistry) nomenclature:

1. Identify the Longest Carbon Chain: Find the longest continuous carbon chain that includes the carbon atom bonded to the halogen. This chain determines the parent name of the compound.
2. Number the Chain: Number the carbon atoms in the longest chain starting from the end nearest to the halogen atom. This ensures that the halogen gets the lowest possible number.
3. Name the Halogen as a Prefix: The halogen is named using its prefix form: fluorine becomes fluoro-, chlorine becomes chloro-, bromine becomes bromo-, and iodine becomes iodo-.
4. Assign a Number to the Halogen: The number of the carbon to which the halogen is attached is placed in front of the halogen prefix.
5. Combine the Names: The final name is constructed by combining the numbered halogen prefix with the name of the parent alkane. If there are multiple halogens or different substituents, list them in alphabetical order, using prefixes like di-, tri-, etc.

How to name alkyl halides using IUPAC?

To name alkyl halides (haloalkanes) using the IUPAC system, follow these steps:

1. Identify the Longest Carbon Chain: Find the longest continuous carbon chain in the molecule. This chain will serve as the base name of the alkyl halide, using the standard alkane naming (methane, ethane, propane, etc.).
2. Number the Chain: Assign numbers to the carbon atoms in the main chain starting from the end nearest to the halogen atom. This ensures that the halogen gets the lowest possible number.
3. Name the Halogen: The halogen is treated as a substituent and is given a prefix based on its element: fluorine (fluoro-), chlorine (chloro-), bromine (bromo-), or iodine (iodo-).
4. Locate the Halogen: Use the number from step 2 to indicate the position of the halogen on the main chain. If there are multiple halogens, use prefixes such as di-, tri-, tetra-, etc., to indicate the quantity, and list them in alphabetical order if different types are present.
5. Combine the Elements: Write the name as one word, placing the halogen prefix(es) before the base name of the alkane, and use hyphens to separate numbers.